Peruvian Journal of Agronomy http://revistas.lamolina.edu.pe/index.php/jpagronomy/index RESEARCH ARTICLE Received for publication: 30 October 2020 Accepted for publication: 20 January 2021 ISSN: 2616-4477 © The authors. Published by Universidad Nacional Agraria La Molina DOI: http://dx.doi.org/10.21704/pja.v5i1.1656 Genetic behavior for seed yield and yield components in sesame (Sesamum indicum L.) under normal irrigation and water stress conditions Comportamiento genético del rendimiento de semillas y componentes del rendimiento en sésamo (Sesamum indicum L.) en condiciones normales de riego y estrés hídrico Suzan Abd El- Latif Kamel Ibrahim1; Mohamed Ali Abdelsatar1*; Mohamed Abd El-Raheem Ahmed1; Magdy M. Niazy2 *Corresponding author: mohamedtemraz1@yahoo.com *https://orcid.org/0000-0003-0780-1444 Abstract Six divergent genotypes of sesame (Sesamum indicum L.) were crossed using a half diallel excluding reciprocal crosses, to estimate heterosis, combining ability and nature of gene action for studied traits under two irrigation regimes. The two irrigation regimes were normal irrigation conditions with amount of applied water 5952.38 m3/ha and water stress conditions with amount of applied water 2976.19 m3/ha at Etay-El-Baroud Agricultural Research Station, Behaira governorate, Agricultural Research Center, Egypt during 2019 summer season. A randomized complete block design with three replications was used for each irrigation regimes. The variation of genotypes and their components from parents, crosses and parents versus crosses were highly significant for all studied traits under both irrigation regimes and their interactions with irrigation. Variation attributable to general and specific combining ability was highly significant for seed yield and yield components under both irrigation regimes. The parents L92 and L110 were the best combiners for seed weight per plant and most of its components under both irrigation regimes. The best F1 cross combination was L92 × L110 in specific combining ability and heterotic effects over mid- and better-parents under both irrigation regimes for seed weight per plant and most of its attributes. The preponderance of additive gene action in the inheritance of most studied traits was observed, that further confirmed by its significance and the value of average degree of dominance exceeding the unity. Narrow-sense heritability varied from 0.19 for number of branches per plant to 0.47 for 1000 seed weight under normal irrigation, whereas, under water stress conditions, it ranged from 0.14 for number of branches per plant to 0.42 for fruiting zone length. Parents L95 and L93 under normal irrigation and L93 and L110 under water stress conditions carried mostly genes with dominant effects for seed weight per plant, in contrary, L92 and L110 under normal irrigation and L92 and L12 under water stress conditions carried mostly recessive alleles for seed weight per plant. Hence, the results will be used to develop a sesame breeding scheme at Etay-El-Baroud Agricultural Research Station. Key words: Sesame, Sesamum indicum, Half diallel analysis, Heterosis, Combining ability, Gene action, Irrigation. Resumen Se cruzaron seis genotipos divergentes de sésamo (Sesamum indicum L.) utilizando un medio dialélico excluyendo cruces recíprocos, para estimar la heterosis, combinando la capacidad y la naturaleza de la acción de los genes para los rasgos estudiados bajo dos regímenes de riego. Los dos regímenes de riego fueron condiciones de riego normales con una cantidad de agua aplicada de 5952,38 m3/ha y condiciones de estrés hídrico con una cantidad de agua aplicada de 2976,19 m3/ha en la Estación de Investigación Agrícola de Etay-El-Baroud, gobernación de Behaira, Centro de Investigación Agrícola, Egipto durante 2019 temporada de verano. Se utilizó un diseño de bloques completos al azar con tres repeticiones para cada régimen de riego. La variación de genotipos y sus componentes de padres, cruces y padres versus cruces fue altamente significativa para todos los rasgos estudiados bajo ambos regímenes de riego y sus interacciones con el riego. La variación atribuible a la capacidad de combinación general y específica fue muy significativa para el rendimiento de semillas y los componentes del rendimiento en ambos regímenes de riego. Los padres 1 Oil Crops Research Department, Field Crops Research Institute, Agricultural Research Center, Giza, Egypt. 2 Soils, Water and Environment Research Institute, ARC, Giza, Egypt How to cite this article: Ibrahim Suzan A. K., Abdelsatar, M. A., Ahmed, M. A., & Niazy, M. M. (2021). Genetic behavior for seed yield and yield components in sesame (Sesamum indicum L.) under normal irrigation and water stress conditions. Peruvian Journal of Agronomy, 5(1), 1–17. http://dx.doi.org/10.21704/pja.v5i1.1656 Patricia Sello Genetic behavior for seed yield and yield components in sesame (Sesamum indicum L.) under normal irrigation and water stress conditions January - April 2021 2 Introduction Sesame is one of the important oil crops in Egypt. It plays a vital and effective role in covering the requirements of oilseeds. To increase the productivity of its seeds, increased genetic diversity is necessary. Therefore, the ultimate goal of sesame breeder is to collect information on heterotic effects, per se performance, general and specific combining ability effects of parents along with genetic components of variance for yield and associated traits. The estimation of heterosis either of mid or better parents heterosis played a major role in identifies the desirable cross combinations in preferred direction. Moreover, combining ability analysis is a common biometrical tool in half diallel analysis to identify the best general combiners and the desirable specific cross combinations. Moreover, another method of half diallel analysis as Hayman (1954a, 1954b, and 1960) and Jinks (1954) provides the breeder with the detailed information on nature gene action and the genetic control in the studied traits. This information helps breeder in selection of preferred parents for future crosses at breeding programs to improve the sesame yield and related traits. For achieving this objective, the efforts in this study aimed to estimate: heterotic effects, combining ability effects, nature of gene action controlling genetic expression of the studied traits under both normal irrigation and water stress conditions. Materials and Methods Plant materials Set of six parental sesame genotypes that had genetically distinct in their morphological traits were mated by a half-diallel mating design (excluding reciprocal crosses) during the 2018 summer season under Etay-El-Baroud/ Behaira Agricultural Research Station, Agricultural Research Center (ARC), Egypt, to create 15 single-cross combinations. These parental sesame genotypes were labeled as L95 (P1), L92 (P2), L28 (P3), L12 (P4), L93 (P5) and L110 (P6) during the hybridization program by a half-diallel mating design (Table 1). The source of these breeding materials was the Oil Crops Research Department, Field Crops Research Institute, ARC, Egypt. The compositions and chemical properties of soil site samples were analyzed according to Jackson (1973) and are shown in Table 2. The wheat crop was sown in the field in the previous campaign. Our experiment was sown in the summer season 15th June 2019. Experimental design and cultural practices The field evaluation trial of the parents and their F1 crosses was conducted in the summer season of 2019 under normal irrigation conditions (NI) with applied water amount of 5952.38 m3/ha and water stress conditions L92 y L110 fueron los mejores combinadores para peso de semilla por planta y la mayoría de sus componentes bajo ambos regímenes de riego. La mejor combinación cruzada F1 fue L92 × L110 en capacidad de combinación específica y efectos heteróticos sobre padres medios y mejores bajo ambos regímenes de riego para el peso de semilla por planta y la mayoría de sus atributos. Se observó la preponderancia de la acción aditiva de genes en la herencia de los rasgos más estudiados, lo que se confirmó además por su importancia y el valor del grado medio de dominancia superior a la unidad. La heredabilidad en sentido estricto varió de 0,19 para el número de ramas por planta a 0,47 para el peso de 1000 semillas bajo riego normal, mientras que, en condiciones de estrés hídrico, varió de 0,14 para el número de ramas por planta a 0,42 para la longitud de la zona de fructificación. Los padres L95 y L93 bajo riego normal y L93 y L110 bajo condiciones de estrés hídrico portaban principalmente genes con efectos dominantes para el peso de semilla por planta, por el contrario, L92 y L110 bajo riego normal y L92 y L12 bajo condiciones de estrés hídrico portaban principalmente alelos recesivos para semilla peso por planta. Por lo tanto, los resultados se utilizarán para desarrollar un programa de mejoramiento de sésamo en la Estación de Investigación Agrícola de Etay-El-Baroud. Palabras clave: Sésamo, Sesamum indicum, Análisis medio dialélico, Heterosis, Habilidad combinatoria, Acción genética, Irrigación. Parents Name Pedigree Origin L95 Introduce 432 Unknown USA 1976 L92 B-42 Unknown Egypt L28 Hybrid 133 NA272 × Giza 32 Egypt L12 Hybrid 102 NA217 × Giza 25 Egypt L93 Introduce 588 Unknown Mexico 1986 L110 Introduce 304 Unknown USA 1975 Table 1. Name, pedigree and origin of sesame parental genotypes Soil properties Value Composition Sand (%) 16.75 Silt (%) 34.85 Clay (%) 48.40 Soil texture Clay Chemical analysis Value Concentration of N (mg kg-1) 156 Concentration of P (mg kg-1) 7.89 Concentration of K (mg kg-1) 374 Electrical conductivity (ds/m) 1.59 pH 7.46 Table 2. Soil composition and chemical properties of the upper 30 cm of the experimental soil for Etay-El-Baroud station A. K. Ibrahim Suzan; M. A. Abdelsatar; M. A. Ahmed; M. M. Niazy Peruvian Journal of Agronomy 5(1): 1–17 (2021) 3 (WSC) with applied water amount of 2976.19 m3/ha using a randomized complete block design with three replicates for each irrigation regimes. Surface irrigation system was used through siphon pip with the rate of water flow (3 L/s) to regulate and calculate the amount of applied water for each irrigation treatment. The distribution of the amount of applied water was based on the irrigation time taken for each treatment. Where, the irrigation time under WSC was half that of NI. Four irrigations were applied for each treatment. The experimental plots consisted of two ridges, 5 m long and 60 cm wide, with a spacing of 10 cm between individual plants. Seeds of parents and their F1 crosses were hand-planted in adjacent plots. The sesame seedlings were thinned to keep one plant per hill on one side of the ridge. The other cultural practices were done as recommended by Oil Crops Research Department, Field Crops Research Institute, ARC, Egypt. Data collection Ten plants were randomly taken from each plot to measure the average of plant height (cm), fruiting zone length (cm), capsules length (cm), number of branches per plant, 1000-seed weight (g) and seed weight per plant (g), which was adjusted to 15.5 % seed moisture. Days to 50 % flowering was recorded on a plot basis. Seed oil content (%) was determined, after drying seed at 70°C for 48 h, by the Soxhlet extraction technique, using diethyl ether (Association of Official Analytical Chemists [AOAC], 1990). Statistical analysis Combined analysis according to Steel et al. (1997) was performed for identifying irrigation effects on genetic variance and its components and the interaction between them, that after confirmed of homogeneity from the error variance. Combining ability analysis for all studied traits was done according to method 2 model 1 of Griffing (1956) for each irrigation regimes. Moreover, analysis of Jones (1965) was performed for partitioning of dominance genetic effects (b) into three effects as b1 which refers to test of mean deviation of F1 from their mid-parental values, b2 which refers to test of whether mean dominance deviation of the F1 from their mid- parental values within each array differs over arrays, and b3 which refers to test of dominance deviation that is unique to each F1, for each irrigation regimes. To judge the gene action controlling all studied traits, baker ratio was done according to Baker (1978) as follow: 2MSgca/(2MSgca+ Mssca). Heterosis was determined for individual crosses as the percentage deviation of F1 means performance from either mid parents or better parents values at both irrigation regimes. To determine the nature of dominance, the potence ratio as according to Wigan (1944) and Mather and Jinks (1971) was computed by the formulae: Potence ratio (P) =F1-MP/ HP-MP. Where P refers to relative potency of the gene set and F1, MP and HP are the means of the F1 generations, mid parents, and the higher parents, respectively. Complete dominance was indicated when P = +1; while partial dominance is indicated when “P” is between (−1 and +1), except the value zero, which indicates the absence of dominance. It is considered over- dominance when potence ratio exceeds ±1. The positive and negative signs indicate the direction of the dominance of either parent. Hayman’s diallel analysis (Hayman, 1954b) was performed to determine the genetic components and related genetic parameters. The adequacy of simple additive- dominance model, and the proportion of dominant and recessive alleles in the sesame parental genotypes, along with degree of dominance under two irrigation regimes were determined by covariance (Wr)/variance (Vr) graph according to Jinks (1954), Hayman (1954a), and Mather and Jinks (1982). In addition, the adequacy of simple additive-dominance model was judged using three scaling tests: uniformity of Wr and Vr (t2-test), joint regression analysis, and variance analysis of (Wr + Vr) and (Wr – Vr) for all studied traits under two irrigation regimes. When the previous three tests are failure or inadequacy, the additive- dominance model is completely invalid. However, the additive-dominance model is partially adequate, if one of these tests achieves the assumptions. Accordingly, partially adequate or completely adequate types can be considered as guide for extra analysis to determine the genetic components of variation (Johnson & Askel, 1964; Wilson et al., 1978). MS-EXCEL (2007) with spreadsheet formula commands was used to conduct the statistical analyses and figures were elaborated in Excel, too in this study. Results and Discussion Analysis of variance Highly significant genetic variability in respect to genotypes and its components of parents and their F1 crosses were detected for all studied traits under both contrasting irrigation regimes (Tables 3 and 4) and their combined analysis. This indicated that existence of significant genetic variability among these populations, and hence increasing the chances of improving these traits. Similar results were obtained by Ramesh et al. (2014), Fahmy et al. (2015), Abd EL-Satar et al. (2016), Ismail et al. (2020) and Jeeva et al. (2020). The considerable heterosis among created cross combinations was detected for all studied traits under both contrasting irrigation regimes as verified by highly significant parents vs. F1 crosses, as presented by Jones Genetic behavior for seed yield and yield components in sesame (Sesamum indicum L.) under normal irrigation and water stress conditions January - April 2021 4 (1965) where b1 refers to mean deviation of F1’s from the mid-parents. Similarly, the high significance of b2 values were obtained for all studied traits under both contrasting irrigation regimes, indicating asymmetry of gene distribution among parents used. Moreover, item b3 was highly significant for all studied traits under contrasting irrigation regimes indicating interactions of allelic and non-allelic were inconsistent (Kearsy, 1965; Mather & Jinks, 1971). Irrigation regimes and their interaction with genotypes, parents, crosses and parents versus crosses in the combined analysis (Table 4) had highly significant effects on performance of all studied traits, indicating that irrigations had valuable environmental variability, which lead to difference of all population performance ranking from one irrigation to another. This could be attributed to providing plant with proper irrigation will help nutrients absorption from the soil which lead to increased vegetative growth and thereby increase metabolic rate and thus increase yield components, and consequently increasing seed weight per plant with compared to water stress conditions. Mean performance Mean performance of six parental sesame genotypes and their respective 15 F1 crosses for all studied traits are presented in Table 5a and 5b. In comparison with their parents, all cross combinations were earliness in flowering by 6.11 % under NI and 5.86 % under WSC and shorter in plant height by 8.29 % at NI and 8.50 % under WSC. Conversely, in comparison with their parents, the progress increase was observed in fruiting zone length by 40.99 % under NI and 30.76 % under WSC, capsules length by 18.91 % under NI and 17.51 % under WSC, number of branches per plant by 75.85 % under NI and 77.89 % under WSC, 1000-seed weight by 27.36 % under NI and 26.68 % under WSC, seed weight per plant by 16.55 % under NI and 30.48 % under WSC and seed oil content by 2.51 % under NI and 4.95 % under WSC. This could be attributed to water stress Source of variance df Days to 50%flowering Plant height Fruiting zone length Capsules length N S N S N S N S Replications 2 0.33 0.11 9.35 13.29 1.53 1.33 0.00 0.02 Genotypes 20 65.71** 42.31** 677.52** 420.75** 525.35** 227.34** 0.56** 0.28** Parents (P) 5 25.43** 22.09** 832.67** 483.39** 267.44** 64.43** 0.30** 0.15** Crosses (C) 14 70.82** 45.36** 545.02** 350.52** 353.38** 186.05** 0.47** 0.21** P V C 1 195.56** 100.80** 1756.67** 1090.86** 4222.48** 1620.01** 3.23** 1.94** Error 40 0.50 0.76 5.13 4.45 2.72 3.85 0.02 0.01 Source of variance df Number of branches per plant 1000-seed weight Seed weight per plant Seed oil content N S N S N S N S Replications 2 0.30 0.05 0.07 0.01 4.025 13.765 1.11 0.60 Genotypes 20 5.58** 3.04** 1.28** 0.63** 82.764** 87.773** 9.24** 15.83** Parents (P) 5 3.39** 1.56** 0.39** 0.17** 70.809** 58.285** 6.72** 10.36** Crosses (C) 14 2.18** 1.31** 1.09** 0.47** 65.251** 61.070** 9.64** 13.60** P V C 1 64.13** 34.77** 8.37** 5.14** 387.720** 609.037** 16.26** 74.47** Error 40 0.33 0.30 0.02 0.02 7.904 10.738 0.96 1.01 Source of variance d.f Days to 50% flowering Plant height Fruiting zone length Capsules length Number of branches per plant 1000-seed weight Seed weight per plant Seed oil content Irrigation (I) 1 7344.79** 29962.29** 5034.01** 8.26** 49.53** 15.65** 2911.590** 697.90** Reps within I 4 0.22 11.32 1.43 0.01 0.17 0.04 8.895 0.85 Entries (E) 20 22.31** 268.75** 175.53** 0.20** 1.98** 0.44** 39.642** 4.73** E × I 20 85.71** 829.52** 577.17** 0.65** 6.65** 1.47** 130.894** 20.34** Parents (P) 5 9.09** 317.66** 67.08** 0.10** 0.82* 0.13** 29.598* 2.51* P × I 5 38.43** 998.40** 264.78** 0.34** 4.12** 0.43** 99.496** 14.57** Crosses (C) 14 23.47** 220.33** 127.93** 0.15** 0.80** 0.35** 28.484** 4.43** C × I 14 92.71** 675.21** 411.50** 0.52** 2.69** 1.22** 97.837** 18.80** P vs C 1 72.14** 702.02** 1384.17** 1.27** 24.17** 3.33** 246.079** 20.04** P × F1× I 1 224.21** 2145.52** 4458.32** 3.90** 74.73** 10.18** 750.678** 70.69** Error 80 0.63 4.79 3.28 0.02 0.32 0.02 9.321 0.99 Table 3. Mean squares of the six sesame parents and their F1 crosses for earliness, yield and its attributes under normal irrigation(N) and water stress conditions (S) in 2019 season Note: *, ** refers to significant at 5% and highly significant at 1%, respectively Table 4. Mean squares of the six sesame parents and their F1 crosses for earliness, yield and its attributes traits across irrigation regimes in 2019 season Note: *, ** refers to significant at 5% and highly significant at 1%, respectively A. K. Ibrahim Suzan; M. A. Abdelsatar; M. A. Ahmed; M. M. Niazy Peruvian Journal of Agronomy 5(1): 1–17 (2021) 5 led to a decrease in the rate of vegetative growth and thus a decrease in the rates of metabolism, thus reducing the movement of photosynthesis products from the leaves as a source to the seed as a sink, and this will negatively affect the yield components and thus seed weight per plant. The earliest sesame parents in flowering were L12 (60.67 day) and L92 (61.67 day) under NI and L110 (44.00) and L12 (45.33) under WSC and their respective crosses L92 × L110 (51.33 day) and L12 × L110 (51.67 day) under NI and L92 × L110 (40.33 day) and L12 × L110 (40.67 day) under WSC. This indicated that genes responsible for earliness were passed to their F1 crosses. As for plant height, the dwarfest the parents were L93 (124.00 cm) and L28 (125.67 cm) under NI and L28 (96.00 cm) and L93 (97.00 cm) under WSC and their F1 crosses L93 × L110 (109.00) under NI and L93 × L110 (84.33 cm) under WSC, again, genes of dwarfness in the parents passed into their F1 crosses. In case of fruiting zone length, the promising parents were L95 (57.27 cm and 42.57 cm) and L92 (53.00 and 37.52 cm) under both NI and WSC, respectively and their F1 cross combinations L95 × L92 (82.67 cm) and L95 × L28 (82.67 cm) under NI and L95 × L92 (64.27 cm) and L95 × L28 (59.07 cm) under WSC. This may be attributed to genes with positive effect on fruiting zone length transformed to their respective F1 crosses. The largest capsules length was detected in the parents L95 (3.03 cm) and L92 (2.83 cm) under NI and L95 (2.45 cm) and L12 (2.39 cm) under WSC and their genes with positive effect passed to the F1 crosses L95 × L93 (3.83 cm and 3.24 cm) and L95 × L28 (3.77 cm and 3.11 cm) under NI and WSC, respectively. The genes responsible for more branches/ plant passed from the parents as L92 (4.33 branch) and L12 (3.67 branch) under NI and L28 (3.00 branch) and L110 (2.67 branch) under WSC to their F1 crosses as L95 × L110 (7.00 branch) and L12 × L110 (6.00 branch) under NI and L95 × L110 (5.33 branch) and L95 × L12 (4.67 branch) under WSC. The positive effect of genes towards increasing 1000-seed weight transformed from the parents as L95 (3.47 g and 2.72 g) and L92 (3.26 g and 2.58 g) under NI and WSC, respectively to their F1 crosses as L95 × L92 (4.72 g) and L92 × L28 (4.61 g) under NI and L95 × L12 (3.80 g) and L95 × L110 (3.67 g) under WSC. The desirable genes effect on seed weight per plant passed from parents as L92 (41.54 g and 28.57 g) and L110 (35.85 g and 25.17 g) under NI and WSC, respectively to L92 × L110 (51.27 g and 37.53 g) and L28 × L12 (45.16 g and 34.69 g) under NI and WSC. The highest proportion of seed oil content was detected in the parents L110 (46.72 %) and L95 (45.84 %) under NI and L95 (52.32%) and L12 (48.31%) under WSC, which passed to their F1 crosses L92 × L12 (48.79 %) and L95 × L110 (48.36 %) under NI and L95 × L92 (55.50 %) and L92 × L12 (52.90 %) under WSC. This result corroborates with the findings of Fahmy et al. (2015), Abd EL-Satar et al. (2016), Ismail et al. (2020) and Jeeva et al. (2020), who observed significant genetic variations among parents and their F1 crosses for all studied traits. Genotypes Days to 50%flowering Plant height Fruiting zone length Capsules length N S N S N S N S L95 65.67 49.33 165.67 128.67 57.27 42.57 3.03 2.45 L92 61.67 49.00 132.33 105.67 53.00 37.52 2.83 2.37 L28 68.33 51.33 125.67 96.00 38.00 37.41 2.17 1.88 L12 60.67 45.33 144.33 105.00 46.00 37.12 2.77 2.39 L93 62.00 47.67 124.00 97.00 37.00 36.12 2.70 2.14 L110 64.67 44.00 154.00 118.00 34.00 28.24 2.40 2.08 LSD 5% 0.30 0.37 0.97 0.90 0.70 0.84 0.06 0.04 LSD 1% 0.40 0.50 1.29 1.20 0.94 1.12 0.08 0.06 L95 × L92 61.33 42.67 139.00 107.00 82.67 64.27 3.37 2.53 L95 × L28 60.00 45.67 157.33 120.00 82.67 59.07 3.77 3.11 L95 × L12 68.33 52.67 122.67 94.33 75.67 56.75 3.47 2.74 L95 × L93 63.33 48.33 145.33 114.00 62.33 44.79 3.83 3.24 L95 × L110 57.33 42.00 125.00 93.67 64.00 52.10 3.23 2.58 L92 × L28 63.00 48.33 130.67 101.67 63.00 53.68 2.80 2.41 L92 × L12 64.00 47.00 122.33 93.33 59.33 42.92 3.33 2.67 L92 × L93 56.67 42.00 135.67 103.33 50.33 37.90 3.20 2.65 L92 × L110 51.33 40.33 120.00 89.67 49.00 37.84 2.87 2.50 L28 × L12 64.67 42.00 132.33 103.33 62.00 46.30 2.83 2.54 L28 × L93 64.33 46.00 122.00 92.00 63.67 45.55 2.83 2.54 L28 × L110 57.67 51.33 146.00 113.00 53.67 42.08 2.43 2.30 L12 × L93 56.33 44.00 122.00 93.00 54.33 45.07 2.73 2.30 L12 × L110 51.67 40.67 110.33 85.00 49.33 40.12 3.20 2.41 L93 × L110 59.00 41.67 109.00 84.33 63.00 47.37 3.37 2.60 LSD 5% 0.48 0.59 1.53 1.42 1.11 1.32 0.10 0.07 LSD 1% 0.64 0.79 2.04 1.90 1.49 1.77 0.13 0.09 Table 5a. Mean performance of six parental sesame genotypes and their 15 F1 cross combinations for days to 50% flowering, plant height, fruiting zone length and capsules length under normal irrigation (N) and water stress conditions (S) in 2019 season Genetic behavior for seed yield and yield components in sesame (Sesamum indicum L.) under normal irrigation and water stress conditions January - April 2021 6 Combining ability Types of combining ability either general (GCA) or specific (SCA) and their respective symbol in Jones (1965) as additive gene action (a) and non-additive (b) were highly significant in respect to all studied traits under both contrasting irrigation regimes (Table 6) and their combined analysis (Table 7). This indicated that both types of genes either additive or non-additive played a major role in the inheritance of all studied traits. Whereas, the additive gene action was preponderant in the gene expression of most studied traits under both irrigation regimes and their combined analysis as verified by baker ratio and (a/b) ratio of Jones method. Moreover, interaction of irrigation with both types of combining ability was highly significant for all studied traits, indicating that types of gene action had highly significant response to environmental variability. In the approach used by Jones (1965), directional dominance (b1) was significant under both irrigation regimes and their combined analysis, indicating that the existence of directional dominance with the preponderance of additive gene action (Tables 6 and 7). The significance of distribution of dominant and recessive alleles in parents (b2) for all studied traits was observed under both irrigation regimes and their combined analysis. This showed the presence of asymmetrical distribution of dominant and recessive genes in parents. Specific gene interactions or epistasis was detected for all studied traits under both irrigation regimes and their combined analysis, as revealed by the significance of dominance deviation unique to F1s (b3). Similar results were reported by Fahmy et al. (2015), Abd EL-Satar et al. (2016) and Jeeva et al. (2020), they stated that additive gene action had greater contribution in the inheritance of seed yield and its contributing traits. Combining ability effects: General combining ability effects General combining ability (GCA) effects were estimated for the parental sesame genotypes and specific combining ability (SCA) effects for F1 crosses are presented in Table 8. The best combiners with highly significant and negative estimates of GCA effects for earliness in flowering were exhibited by L110 and L92 under NI and L110 and L12 under WSC. Moreover, L93 (-5.82 and -4.00) and L12 (-3.78 and -4.21) in both NI and WSC proved to be good combiners, respectively, again as desirable direction, with highly significant and negative GCA effects towards dwarfness. These parents were considered as good general combiners for these traits and could be used in breeding programs to develop earliness in flowering and short stature varieties. Genotypes Number of branches per plant 1000-seed weight Seed weight per plant Seed oil content N S N S N S N S L95 1.33 1.00 3.47 2.72 29.80 17.67 45.84 52.32 L92 4.33 1.67 3.26 2.58 41.54 28.57 42.69 48.01 L28 2.67 3.00 2.70 2.27 28.49 22.06 44.36 48.26 L12 3.67 2.33 2.89 2.28 30.43 17.45 43.73 48.31 L93 2.33 2.00 2.49 2.06 33.00 24.55 45.63 47.23 L110 3.33 2.67 2.89 2.31 35.85 25.17 46.72 47.59 LSD 5% 0.24 0.23 0.06 0.06 1.20 1.40 0.42 0.43 LSD 1% 0.33 0.31 0.08 0.08 1.60 1.87 0.56 0.57 L95 × L92 5.33 3.67 4.72 3.10 34.04 19.00 44.15 55.50 L95 × L28 3.33 3.00 3.40 2.55 36.68 28.25 43.99 48.48 L95 × L12 5.67 4.67 4.57 3.80 35.00 25.82 47.61 51.65 L95 × L93 4.33 3.33 3.64 2.92 32.72 27.22 45.82 50.83 L95 × L110 7.00 5.33 4.54 3.67 38.00 27.48 48.36 52.90 L92 × L28 5.00 3.67 4.61 3.60 38.13 28.56 44.92 51.77 L92 × L12 5.67 4.00 3.80 2.85 39.98 32.02 48.79 52.90 L92 × L93 4.33 3.00 3.60 2.87 36.75 33.50 47.22 51.77 L92 × L110 5.33 3.67 3.71 3.20 51.27 37.53 46.73 51.77 L28 × L12 4.67 3.33 3.38 2.71 45.16 34.69 43.03 48.65 L28 × L93 5.33 3.67 2.52 2.60 42.12 33.91 46.02 50.28 L28 × L110 4.67 3.33 3.50 2.73 38.85 31.37 47.19 51.43 L12 × L93 5.33 3.33 3.50 2.70 37.39 27.39 44.23 47.94 L12 × L110 6.00 4.67 3.46 2.81 35.58 26.91 44.09 47.66 L93 × L110 5.67 3.67 3.39 2.89 38.48 28.24 47.14 51.87 LSD 5% 0.39 0.37 0.10 0.10 1.89 2.21 0.66 0.68 LSD 1% 0.52 0.49 0.13 0.13 2.53 2.95 0.88 0.91 Table 5b. Mean performance of six parental sesame genotypes and their 15 F1 cross combinations for number of branches per plant, 1000-seed weight, seed weight per plant and seed oil content under normal irrigation (N) and water stress conditions (S) in 2019 season A. K. Ibrahim Suzan; M. A. Abdelsatar; M. A. Ahmed; M. M. Niazy Peruvian Journal of Agronomy 5(1): 1–17 (2021) 7 The positive direction of GCA effects for seed weight per plant and its components is desirable. The best GCA effects was detected in L95 and L92 under NI and L95 and L28 under WSC for fruiting zone length, L95 and L93 under both irrigation regimes for capsules length, L110 and L12 under both irrigation regimes for branches number per plant, L95 and L92 under both irrigation regimes for 1000- seed weight, L92 and L110 under both irrigation regimes for seed weight per plant and L110 and L93 under NI and L95 and L92 under WSC for seed oil content. This result corroborates with the findings of Fahmy et al. (2015), Abd EL-Satar et al. (2016), Ismail et al. (2020) and Jeeva et al. (2020), they created GCA effects in the desired direction for seed yield and yield components. Specific Combining Ability Effects The created combinations showed a large variation in the SCA effects (Tables 9a, 9b) either in the desired or undesired direction under normal irrigation and water stress conditions. Accordingly, the possibility of selection for the desired effects, where a negative effect on days to 50 % flowering and plant height is desirable, but a positive effect on seed yield and its components is desirable. SOV df Days to 50%flowering Plant height Fruiting zone length Capsules length Griffing Jones N S N S N S N S GCA a 5 27.02** 15.74** 301.41** 195.81** 267.95** 107.65** 0.32** 0.10** b1 1 65.19** 33.60** 585.56** 363.62** 1407.49** 540.00** 1.08** 0.65** b2 5 19.82** 2.77** 296.50** 164.43** 63.32** 28.02** 0.05** 0.05** b3 9 15.41** 17.32** 104.63** 71.13** 48.72** 33.03** 0.09** 0.05** SCA b 15 20.20** 13.56** 200.65** 121.73** 144.17** 65.16** 0.14** 0.09** Total 20 21.90** 14.10** 225.84** 140.25** 175.12** 75.78** 0.19** 0.09** Error 40 0.17 0.25 1.71 1.48 0.91 1.28 0.01 0.004 Baker ratio 0.73 0.70 0.75 0.76 0.79 0.77 0.82 0.70 SOV df Number of branches per plant 1000-seed weight Seed weight per plant Seed oil content Griffing Jones N S N S N S N S GCA a 5 1.39** 0.49** 0.70** 0.20** 34.76** 35.44** 3.00** 7.36** b1 1 21.38** 11.59** 2.79** 1.71** 129.24** 203.01** 5.42** 24.82** b2 5 0.69* 0.70** 0.11** 0.02** 13.99** 9.45* 1.44** 3.99** b3 9 0.60* 0.30* 0.19** 0.15** 19.87** 17.53** 3.77** 2.66** SCA b 15 2.02** 1.19** 0.34** 0.21** 25.20** 27.20** 3.11** 4.58** Total 20 1.86** 1.01** 0.43** 0.21** 27.59** 29.26** 3.08** 5.28** Error 40 0.11 0.10 0.01 0.01 2.63 3.58 0.32 0.34 Baker ratio 0.58 0.45 0.81 0.65 0.73 0.72 0.66 0.76 Table 6. Half diallel’s analyses with Griffing method 2 model 1 (1956) and Jones (1965) for all studied traits across normal irrigation (N) and water stress conditions (S) in 2019 season Note: “GCA and SCA of Griffing (1956)” and “a=additive effects, b=total non-additive (dominance) effects, b1=mean deviation of F1’s from their mid-parents, b2=test if there is equal or unequal distribution among parents and b3=detect existence of unique dominance of each F1, i.e., presence of considerable amount of heterotic effect specific to some crosses of Jones (1965) modification”;*, ** significant at 0.05 and 0.01 level of probability, respectively Source d.f Days to 50% flowering Plant height Fruiting zone length Capsules length Number of branches per plant 1000-seed weight Seed weight per plant Seed oil contentGriffing Jones GCA a 4 41.60** 488.90** 354.88** 0.39** 1.41** 0.82** 64.87** 6.28** b1 1 96.19** 936.02** 1845.56** 1.70** 32.22** 4.44** 328.11** 26.72** b2 4 14.15** 446.52** 77.10** 0.08** 1.18** 0.10** 22.13** 4.72** b3 5 24.43** 172.61** 75.04** 0.13** 0.84** 0.30** 32.67** 4.94** SCA b 10 25.79** 314.81** 193.76** 0.22** 3.04** 0.51** 48.85** 6.32** a*I 4 1.16** 8.32** 20.72** 0.03** 0.47** 0.08** 5.33 4.08** b1*I 1 2.59** 13.16** 101.94** 0.03* 0.74** 0.07** 4.15 3.52** b2*I 4 8.44** 14.41** 14.24** 0.01 0.21 0.03** 1.31 0.71 b3*I 5 8.30** 3.15 6.71** 0.01* 0.07 0.04** 4.72 1.49** SCA × I b × I 10 7.97** 7.57** 15.57** 0.01** 0.16 0.04** 3.54 1.37** Error 80 0.21 1.60 1.09 0.01 0.11 0.01 3.11 0.33 Table 7. Half diallel’s analyses with Griffing method 2 model 1 (1956) and Jones (1965) for all studied traits across irrigation regimes in 2019 season Note: I=irrigation regimes; “GCA and SCA of Griffing (1956)” and “a=additive effects, b=total non-additive (dominance) effects, b1=mean deviation of F1’s from their mid-parents, b2=test if there is equal or unequal distribution among parents and b3=detect existence of unique dominance of each F1, i.e., presence of considerable amount of heterotic effect specific to some crosses of Jones (1965) modification”; *, ** significant at 0.05 and 0.01 level of probability, respectively Genetic behavior for seed yield and yield components in sesame (Sesamum indicum L.) under normal irrigation and water stress conditions January - April 2021 8 Table 8. General combining ability effects of six parental sesame genotypes for all studied traits under normal irrigation (N) and water stress conditions (S) in 2019 season Parents Days to 50%flowering Plant height Fruiting zone length Capsules length N S N S N S N S L95 1.79** 1.19** 11.51** 9.21** 10.22** 6.32** 0.33** 0.20** L92 -0.96** -0.26 -2.03** -0.79 1.28** 0.01 0.02 0.01 L28 2.38** 1.94** 1.39** 1.17** 0.11 1.24** -0.26** -0.10** L12 -0.13 -0.43* -3.78** -4.21** -0.93** -0.78* 0.01 -0.01 L93 -0.46** -0.39* -5.82** -4.00** -4.05** -2.34** 0.04 0.02 L110 -2.62** -2.06** -1.28** -1.37** -6.64** -4.45** -0.14** -0.12** LSD gi 5% 0.27 0.33 0.85 0.79 0.62 0.74 0.05 0.04 LSD gi 1% 0.36 0.44 1.14 1.06 0.83 0.99 0.07 0.06 LSD gi-gj 5% 0.73 0.90 2.34 2.18 1.71 2.03 0.15 0.12 LSD gi-gj 1% 0.98 1.21 3.14 2.92 2.28 2.72 0.20 0.16 Parents Number of branches per plant 1000-seed weight Seed weight per plant Seed oil content N S N S N S N S L95 -0.43** -0.13 0.39** 0.22** -2.96** -3.67** 0.27 1.45** L92 0.32** -0.21* 0.29** 0.13** 2.94** 1.91** -0.28 0.92** L28 -0.43** 0.00 -0.23** -0.13** -0.23 1.06 -0.69** -0.65** L12 0.36** 0.21* -0.02 -0.04 -0.72 -1.34* -0.53** -0.87** L93 -0.26* -0.25* -0.38** -0.21** -0.79 0.86 0.28 -0.65** L110 0.44** 0.38** -0.04 0.02 1.76** 1.18 0.94** -0.20 LSD gi 5% 0.22 0.21 0.06 0.06 1.06 1.23 0.37 0.38 LSD gi 1% 0.29 0.27 0.08 0.08 1.42 1.65 0.49 0.51 LSD gi-gj 5% 0.60 0.56 0.16 0.16 2.91 3.39 1.01 1.04 LSD gi-gj 1% 0.80 0.76 0.21 0.22 3.89 4.54 1.36 1.39 Note: *, ** refers to significant at 5% and highly significant at 1%, respectively Table 9a. Specific combining ability effects of 15 F1 cross combinations for days to 50% flowering, plant height, fruiting zone length and capsules length under normal irrigation (N) and water stress conditions (S) in 2019 season. Crosses Days to 50%flowering Plant height Fruiting zone length Capsules length N S N S N S N S L95 × L92 -0.55 -4.04** -3.14** -3.23** 14.01** 13.43** 0.00 -0.17** L95 × L28 -5.21** -3.25** 11.78** 7.82** 15.18** 7.00** 0.68** 0.51** L95 × L12 5.62** 6.13** -17.72** -12.48** 9.22** 6.70** 0.12 0.04 L95 × L93 0.95** 1.75** 6.99** 6.98** -0.99 -3.70** 0.45** 0.53** L95 × L110 -2.88** -2.92** -17.89** -15.98** 3.26** 5.72** 0.04 -0.01 L92 × L28 0.54 0.88* -1.35 -0.52 4.45** 7.92** 0.03 0.01 L92 × L12 4.04** 1.92** -4.51** -3.48** 1.83* -0.82 0.30** 0.18** L92 × L93 -2.96** -3.13** 10.86** 6.32** -4.05** -4.29** 0.13* 0.13** L92 × L110 -6.13** -3.13** -9.35** -9.98** -2.80** -2.23* -0.02 0.12* L28 × L12 1.37** -5.29** 2.07* 4.57** 5.66** 1.32 0.08 0.15** L28 × L93 1.37** -1.33** -6.22** -6.98** 10.45** 2.13* 0.04 0.13* L28 × L110 -3.13** 5.67** 13.24** 11.40** 3.03** 0.78 -0.17** 0.02 L12 × L93 -4.13** -0.96* -1.05 -0.60 2.16** 3.67** -0.32** -0.21** L12 × L110 -6.63** -2.63** -17.26** -11.23** -0.26 0.83 0.33** 0.03 L93 × L110 1.04** -1.67** -16.55** -12.10** 16.53** 9.64** 0.46** 0.20** LSD Sij 5% 0.60 0.75 1.93 1.80 1.41 1.68 0.12 0.10 LSD Sij 1% 0.81 1.00 2.59 2.41 1.88 2.24 0.17 0.13 LSD sij-sik 5% 1.09 1.35 3.50 3.26 2.55 3.03 0.22 0.18 LSD sij-sik 1% 1.46 1.80 4.68 4.36 3.41 4.05 0.30 0.24 LSD sij-skl 5% 1.01 1.25 3.24 3.02 2.36 2.80 0.21 0.17 LSD sij-skl 1% 1.35 1.67 4.33 4.04 3.15 3.75 0.28 0.22 Note: *, ** refers to significant at 5% and highly significant at 1%, respectively High and negative SCA effects was observed in L12 × L110, and L92 × L110 under NI and L28 × L12 and L95 × L92 under WSC for earliness in flowering and L95 × L110 and L95 × L12 under both irrigation regimes for plant height. Conversely, high and positive SCA effects were detected in L93 × L110 and L95 × L28 under NI and L95 × L92 and L93 × L110 under WSC for fruiting zone length, the cross combinations L95 × L28 and L93 × L110 A. K. Ibrahim Suzan; M. A. Abdelsatar; M. A. Ahmed; M. M. Niazy Peruvian Journal of Agronomy 5(1): 1–17 (2021) 9 under NI and L95 × L93 and L95 × L28 under WSC had high and positive SCA effects for capsules length. In case of number of branches per plant, L95 × L110 and L28 × L93 under NI and L95 × L110 and L95 × L12 under WSC possessed high and positive SCA effects. The promising created combinations for 1000-seed weight was detected in L92 × L28 and L95 × L12 under NI and L95 × L12 and L92 × L28 under WSC. The best SCA effects for seed weight per plant were observed in L92 × L110 and L28 × L12 under NI and L28 × L12 and L92 × L110 under WSC. The good cross combinations for seed oil content were shown by L92 × L12 and L95 × L12 under NI and L95 × L92 and L92 × L12 under WSC. This result corroborates with the findings of Fahmy et al. (2015), Abd EL-Satar et al. (2016), Ismail et al. (2020) and Jeeva et al. (2020), found that the genetic divergence among the parental genotypes had the largest effect on generated cross combinations, especially in estimation of SCA effects for seed yield and yield components. Heterotic effects Two types of heterosis i.e., mid parents heterosis (MPH) and better parents heterosis (BPH) were estimated to identify the best cross combinations (Tables 10a, 10b, 10c, 10d). Three types of cross combinations i.e. High × High, High × Low or Low × High and Low × Low were detected in created cross combinations, where High (H) refer to significant GCA effects in the desired direction and Low (L) refers to non-significant GCA effects either in positive or negative direction. In case of High × High cross combinations, additive and additive × additive gene actions were governed in the inheritance of traits. Additive gene action predominated in the good combiner (High) and a complementary epistatic effect governed in the poor combiner (Low) as High × Low, so these two gene actions involved in gene expression of cross combination as described by Salimath and Bahl (1985). The cross combinations had Low × Low general combiners, indicating that non-additive gene action played a prominent role in the inheritance of seed yield traits as presented by Bhutia et al. (2014). The desirable target was negative direction of for MPH and BPH for the earliness in flowering to produce high yield in a short period and short statured plant suitable for mechanical harvesting and resistant to lodging. Accordingly, the best cross combinations with H × H were detected in L92 × L110 over MPH and BPH under both irrigation regimes for earliness in flowering and L12 × L93 over MPH under both irrigation regimes for short statured plants and more crosses with H × L and L × H over MPH and BPH with negative potence ratio exceeding unity under both irrigation regimes. Conversely, the cross combinations with positive direction are desirable for seed weight per plant and its Table 9b. Specific combining ability effects of 15 F1 cross combinations for number of branches per plant, 1000-seed weight, seed weight per plant and seed oil content under normal irrigation (N) and water stress conditions (S) in 2019 season Crosses Number of branches per plant 1000-seed weight Seed weight per plant Seed oil content N S N S N S N S L95 × L92 0.90** 0.71** 0.52** -0.07 -3.04* -6.74** -1.48** 2.79** L95 × L28 -0.35 -0.16 -0.28** -0.36** 2.76* 3.37* -1.22** -2.66** L95 × L12 1.20** 1.30** 0.67** 0.80** 1.58 3.34* 2.23** 0.73 L95 × L93 0.49 0.42 0.10 0.09 -0.64 2.53 -0.37 -0.31 L95 × L110 2.45** 1.80** 0.66** 0.61** 2.09 2.47 1.52** 1.30** L92 × L28 0.57* 0.59* 1.03** 0.77** -1.69 -1.90 0.26 1.16** L92 × L12 0.45 0.71** 0.01 -0.06 0.66 3.96** 3.96** 2.51** L92 × L93 -0.26 0.17 0.17* 0.13 -2.51* 3.24* 1.59** 1.16** L92 × L110 0.03 0.21 -0.06 0.23** 9.46** 6.95** 0.43 0.71 L28 × L12 0.20 -0.16 0.11 0.06 9.01** 7.48** -1.38** -0.17 L28 × L93 1.49** 0.63** -0.39** 0.11 6.03** 4.50** 0.80 1.25** L28 × L110 0.11 -0.33 0.24** 0.01 0.20 1.65 1.31** 1.94** L12 × L93 0.70** 0.09 0.38** 0.12 1.79 0.38 -1.16** -0.88* L12 × L110 0.65* 0.80** -0.01 0.01 -2.57* -0.42 -1.96** -1.61** L93 × L110 0.95** 0.26* 0.28** 0.25** 0.40** -1.29 0.29** 2.38** LSD Sij 5% 0.49 0.47 0.13 0.13 2.40 2.80 0.84 0.86 LSD Sij 1% 0.66 0.62 0.18 0.18 3.21 3.74 1.12 1.15 LSD sij-sik 5% 0.89 0.84 0.24 0.24 4.34 5.06 1.51 1.55 LSD sij-sik 1% 1.20 1.13 0.32 0.32 5.81 6.77 2.02 2.08 LSD sij-skl 5% 0.83 0.78 0.22 0.22 4.02 4.68 1.40 1.44 LSD sij-skl 1% 1.11 1.04 0.29 0.30 5.38 6.27 1.87 1.92 Note: *, ** refers to significant at 5% and highly significant at 1%, respectively Genetic behavior for seed yield and yield components in sesame (Sesamum indicum L.) under normal irrigation and water stress conditions January - April 2021 10 components. Consequently, the best cross combinations with H × H were detected in L95 × L92 under normal irrigation (NI) and L95 × L28 under water stress conditions (WSC) over MPH and BPH for fruiting zone length, L95 × L93 over MPH and BPH under both irrigation regimes for capsules length, L12 × L110 over MPH and BPH under both irrigation regimes for number of branches per plant, L95 × L92 over MPH and BPH under both irrigation regimes for 1000-seed weight, L92 × L110 in MPH and BPH under both irrigation regimes for seed weight per plant, L93 × L110 over MPH and BPH under NI and L95 × L92 over MPH and BPH under WSC for seed oil content as well as more crosses with H × L and L × H over MPH and BPH with positive potence ratio exceeding unity under both irrigation regimes for all studied traits. Similar these findings were reported by Azeez and Morakinyo (2014), Ramesh et al. (2014), Fahmy et al. (2015), Abd EL-Satar et al. (2016), Ismail et al. (2020), and Jeeva et al. (2020), they found that high heterotic effects significantly affected by genetic variability of parental genotypes. Crosses Days to 50%flowering Plant height N S N S MP P BP MP P BP MP P BP MP P BP L95 × L92 -3.66** 1.17 -0.54 -13.22** 39.00 -12.93** -6.71** 0.60 5.04** -8.68** 0.88 1.26 L95 × L28 -10.45** 5.25 -8.63** -9.27** 4.67 -7.43** 8.01** -0.58 25.20** 6.82** -0.47 25.00** L95 × L12 8.18** -2.07 12.64** 11.27** -2.67 16.18** -20.86** 3.03 -15.01** -19.26** 1.90 -10.16** L95 × L93 -0.78 0.27 2.15** -0.34 0.20 1.40 0.35 -0.02 17.20** 1.03 -0.07 17.53** L95 × L110 -12.02** 15.67 -11.34** -10.00** 1.75 -4.55** -21.79** 5.97 -18.83** -24.05** 5.56 -20.62** L92 × L28 -3.08** 0.60 2.16** -3.65** 1.57 -1.36 1.29 -0.50 3.98* 0.83 -0.17 5.90** L92 × L12 4.63** -5.67 5.49** -0.35 0.09 3.68** -11.57** 2.67 -7.56** -11.39** 36.00 -11.11** L92 × L93 -8.36** 31.00 -8.11** -13.10** 9.50 -11.89** 5.85** -1.80 9.41** 1.97 -0.46 6.53** L92 × L110 -18.73** 7.89 -16.76** -13.26** 2.47 -8.33** -16.18** 2.14 -9.32** -19.82** 3.59 -15.14** L28 × L12 0.26 -0.04 6.59** -13.10** 2.11 -7.35** -1.98 0.29 5.31** 2.82 -0.63 7.64** L28 × L93 -1.28* 0.26 3.76** -7.07** 1.91 -3.50** -2.27 3.40 -1.61 -4.66** 9.00 -4.17* L28 × L110 -13.28** 4.82 -10.82** 7.69** -1.00 16.67** 4.41** -0.44 16.18** 5.61** -0.55 17.71** L12 × L93 -8.15** 7.50 -7.14** -5.38** 2.14 -2.94** -9.07** 1.20 -1.61 -7.92** 2.00 -4.12* L12 × L110 -17.55** 5.50 -14.84** -8.96** 6.00 -7.58** -26.03** 8.03 -23.56** -23.77** 4.08 -19.05** L93 × L110 -6.84** 3.25 -4.84** -9.09** 2.27 -5.30** -21.58** 2.00 -12.10** -21.55** 2.21 -13.06** LSD 5% 1.01 1.17 1.25 1.44 3.24 3.74 3.02 3.48 LSD 1% 1.35 1.56 1.67 1.93 4.33 5.00 4.04 4.66 Table 10a. Relative heterosis (MP) and heterbeltiosis (BP) as well as potence ratio (P) of 15 F1 cross combinations for days to flowering and plant height under normal irrigation (N) and water stress conditions (S) in 2019 season. Note: P refers to relative potency of the gene set; *, ** refers to significant at 5% and highly significant at 1%, respectively Crosses Fruiting zone length Capsules length N S N S MP P BP MP P BP MP P BP MP P BP L95 × L92 49.94** 12.91 44.35** 60.50** 9.60 50.99** 14.77** 4.33 10.99** 4.98** 3.27 3.41** L95 × L28 73.55** 3.64 44.35** 47.72** 7.41 38.78** 44.87** 2.69 24.18** 43.72** 3.32 26.98** L95 × L12 46.55** 4.27 32.13** 42.44** 6.20 33.32** 19.54** 4.25 14.29** 13.24** 10.67 11.85** L95 × L93 32.25** 1.50 8.85** 13.86** 1.69 5.23** 33.72** 5.80 26.37** 41.32** 6.25 32.56** L95 × L110 40.25** 1.58 11.76** 47.15** 2.33 22.40** 19.02** 1.63 6.59** 13.76** 1.72 5.31** L92 × L28 38.46** 2.33 18.87** 43.27** 304.00 43.07** 12.00** 0.90 -1.18** 13.25** 1.13 1.40** L92 × L12 19.87** 2.81 11.95** 15.02** 27.79 14.40** 19.05** 16.00 17.65** 12.18** 43.50 11.87** L92 × L93 11.85** 0.67 -5.03** 2.93* 1.54 1.00 15.66** 6.50 12.94** 17.49** 3.43 11.80** L92 × L110 12.64** 0.58 -7.55** 15.07** 1.07 0.84 9.55** 1.15 1.18** 12.34** 1.90 5.48** L28 × L12 47.62** 5.00 34.78** 24.25** 60.93 23.76** 14.86** 1.22 2.41** 19.16** 1.60 6.42** L28 × L93 69.78** 52.33 67.54** 23.90** 13.55 21.75** 16.44** 1.50 4.94** 26.20** 3.95 18.35** L28 × L110 49.07** 8.83 41.23** 28.19** 2.02 12.48** 6.57** 1.29 1.39** 15.99** 3.06 10.24** L12 × L93 30.92** 2.85 18.12** 23.09** 16.91 21.43** 0.00 0.00 -1.20** 1.40** 0.26 -3.77** L12 × L110 23.33** 1.56 7.25** 22.76** 1.68 8.08** 23.87** 3.36 15.66** 7.68** 1.13 0.84** L93 × L110 77.46** 18.33 70.27** 47.20** 3.86 31.16** 32.03** 5.44 24.69** 22.87** 16.11 21.15** LSD 5% 2.36 2.72 2.80 3.24 0.21 0.24 0.17 0.19 LSD 1% 3.15 3.64 3.75 4.33 0.28 0.32 0.22 0.26 Table 10b. Relative heterosis (MP) and heterbeltiosis (BP) as well as potence ratio (P) of 15 F1 cross combinations for fruiting zone length and capsules length under normal irrigation (N) and water stress conditions (S) in 2019 season. Note: P refers to relative potency of the gene set; *, ** refers to significant at 5% and highly significant at 1%, respectively A. K. Ibrahim Suzan; M. A. Abdelsatar; M. A. Ahmed; M. M. Niazy Peruvian Journal of Agronomy 5(1): 1–17 (2021) 11 3-Hayman numerical and graphical analysis 3-1-Adequacy of simple additive-dominance model The validity of the additive-dominance model was discovered through three tests, which differed from partially to full adequate (Table 11), hence that emphasized the need to complete the identification of genetic components and their ratios according to Hayman (1954b). 3-2-Genetic components and their ratios A graphical analysis (Figures 1a, 1b, 2a, 2b, 3a, 3b, 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b) revealed the regression line intercepted the covariance axis below the point of origin in fruiting zone length, number of branches per plant and seed weight per plant under both irrigation regimes, capsule length under NI, and seed oil content under WSC indicating that over-dominance was governed in the inheritance of Crosses Number of branches per plant 1000-seed weight N S N S MP P BP MP P BP MP P BP MP p BP L95 × L92 88.24** 1.67 23.08** 175.00** 7.00 120.00** 40.17** 13.30 36.06** 17.13** 6.48 14.11** L95 × L28 66.67** 2.00 25.00** 50.00** 1.00 0.00 10.44** 0.84 -1.83** 2.27** 0.25 -6.13** L95 × L12 126.67** 2.71 54.55** 180.00** 4.50 100.00** 43.61** 4.84 31.73** 52.23** 5.98 40.00** L95 × L93 136.36** 5.00 85.71** 122.22** 3.67 66.67** 22.17** 1.35 4.90** 22.21** 1.61 7.36** L95 × L110 200.00** 4.67 110.00** 190.91** 4.20 100.00** 42.92** 4.70 30.96** 46.06** 5.74 35.21** L92 × L28 42.86** 1.80 15.38** 57.14** 2.00 22.22** 54.59** 5.74 41.16** 48.42** 7.65 39.59** L92 × L12 41.67** 5.00 30.77** 100.00** 6.00 71.43** 23.55** 3.92 16.55** 17.36** 2.84 10.61** L92 × L93 30.00** 1.00 0.00 63.64** 7.00 50.00** 25.22** 1.87 10.32** 24.03** 2.14 11.51** L92 × L110 39.13** 3.00 23.08** 69.23** 3.00 37.50** 20.65** 3.37 13.69** 31.02** 5.76 24.32** L28 × L12 47.37** 3.00 27.27** 25.00** 2.00 11.11** 21.05** 5.98 16.94** 19.27** 87.67 19.01** L28 × L93 113.33** 17.00 100.00** 46.67** 2.33 22.22** -2.64** -0.65 -6.43** 20.18** 4.09 14.54** L28 × L110 55.56** 5.00 40.00** 17.65** 3.00 11.11** 25.25** 7.42 21.13** 19.13** 20.23 18.01** L12 × L93 77.78** 3.50 45.45** 53.85** 7.00 42.86** 30.24** 4.00 21.08** 24.52** 4.76 18.42** L12 × L110 71.43** 15.00 63.64** 86.67** 13.00 75.00** 19.61** 170.00 19.47** 22.50** 31.00 21.61** L93 × L110 100.00** 5.67 70.00** 57.14** 4.00 37.50** 26.18** 3.52 17.44** 32.27** 5.49 24.93** LSD 5% 0.83 0.96 0.78 0.90 0.22 0.25 0.22 0.26 LSD 1% 1.11 1.28 1.04 1.20 0.29 0.34 0.30 0.34 Table 10c. Relative heterosis (MP) and heterbeltiosis (BP) as well as potence ratio (P) of 15 F1 cross combinations for number of branches per plant and 1000-seed weight under normal irrigation (N) and water stress conditions (S) in 2019 season Note: P refers to relative potency of the gene set; *, ** refers to significant at 5% and highly significant at 1%, respectively Crosses Seed weight per plant Seed oil content N S N S MP P BP MP P BP MP P BP MP p BP L95 × L92 -4.57* -0.28 -18.05** -17.83** -0.76 -33.50** -0.26 -0.07 -3.69** 10.64** 2.48 6.08** L95 × L28 25.84** 11.50 23.08** 42.21** 3.82 28.06** -2.46** -1.49 -4.04** -3.60** -0.89 -7.33** L95 × L12 16.23** 15.52 15.03** 47.07** 74.01 46.14** 6.31** 2.68 3.87** 2.66** 0.67 -1.27 L95 × L93 4.19* 0.82 -0.87 28.97** 1.78 10.90** 0.18 0.78 -0.05 2.12** 0.42 -2.84** L95 × L110 15.76** 1.71 6.00* 28.28** 1.62 9.16** 4.51** 4.76 3.52** 5.89** 1.25 1.11 L92 × L28 8.89** 0.48 -8.22** 12.81** 1.00 -0.04 3.20** 1.67 1.26 7.54** 28.30 7.26** L92 × L12 11.11** 0.72 -3.75 39.19** 1.62 12.10** 12.90** 10.72 11.56** 9.85** 31.62 9.51** L92 × L93 -1.40 -0.12 -11.53** 26.16** 3.46 17.28** 6.94** 2.09 3.50** 8.71** 10.68 7.83** L92 × L110 32.50** 4.42 23.42** 39.67** 6.28 31.37** 4.52** 1.00 0.02 8.30** 19.05 7.83** L28 × L12 53.30** 16.19 48.42** 75.58** 6.47 57.21** -2.31** -3.27 -3.00** 0.76 16.85 0.71 L28 × L93 36.98** 5.04 27.61** 45.52** 8.54 38.16** 2.29** 1.62 0.87 5.31** 4.91 4.19** L28 × L110 20.76** 1.82 8.37** 32.84** 4.99 24.65** 3.62** 1.40 1.01 7.30** 10.40 6.55** L12 × L93 17.90** 4.41 13.30** 30.47** 1.80 11.60** -1.01 -0.48 -3.07** 0.36 0.32 -0.76 L12 × L110 7.37** 0.90 -0.74 26.27** 1.45 6.90* -2.51** -0.76 -5.62** -0.59 -0.80 -1.33 L93 × L110 11.79** 2.85 7.36** 13.60** 10.85 12.20** 2.10** 1.78 0.91 9.40** 24.76 8.99** LSD 5% 4.02 4.64 4.68 5.41 1.40 1.62 1.44 1.66 LSD 1% 5.38 6.21 6.27 7.24 1.87 2.16 1.92 2.22 Table 10d. Relative heterosis (MP) and heterbeltiosis (BP) as well as potence ratio (P) of 15 F1 cross combinations for seed weight per plant and seed oil content under normal irrigation (N) and water stress conditions (S) in 2019 season Note: P refers to relative potency of the gene set; *, ** refers to significant at 5% and highly significant at 1%, respectively Genetic behavior for seed yield and yield components in sesame (Sesamum indicum L.) under normal irrigation and water stress conditions January - April 2021 12 these traits. This was referred through the average degree of dominance (H1/D) 0.5 (Table 12), which had values more than unity for these traits. However, the other cases take the opposite direction. This result corroborates with the findings of Fahmy et al. (2015) and Abd EL-Satar et al. (2016), who found that over-dominance had the major role in the inheritance of most studied traits. The significance of additive (a) and non-additive (b) effects in Jones (1965) analysis (Tables 6 and 7) and additive (D) and two dominance types in Hayman (1954b) analysis (Table 12) indicated the both additive and non-additive genetic components played a major role in the inheritance of all studied traits under both irrigation regimes. However, the additive gene action was preponderant in the gene expression of most studied traits under both irrigation regimes and their combined analysis as verified by baker ratio and (a/b) ratio of Jones method. This was further verified through medium narrow- sense heritability (Table 12) for most studied traits under both irrigation regimes. These finding are in line with the results of Fahmy et al. (2015) and Abd EL-Satar et al. (2016), they found that narrow sense heritability was moderate for seed yield and most yield component traits. Hence, maximizing improvement of most studied traits can be achieved through selection of promising segregates in early generation. H1 and H2 dominance types considerable differed (Table 12) for all studied traits under both irrigation regimes. This difference was a result of an unequal sharing of dominant and recessive genes in the used parents, which was also proved by the H2/4H1 ratio that was less than 0.25 (Table 12) for all studied traits. The F value (Table 12) had positive sign for most studied traits, indicated that the occurrence of recessive alleles was lesser than that of the dominant alleles in the parents, and this was further verified through the ratio of KD/KR, which was more than unity under both irrigation regimes for most cases. The ratio of h2/H2 (Table 12) ranged from one to two pairs, which refers to the number of gene pairs governing in the inheritance of studied traits, confirmed that one to two pairs of dominant genes controlling the inheritance of all studied traits under both irrigation regimes. Same results were obtained by Fahmy et al. (2015). 5-Distribution of dominant and recessive genes among the parents Parental sesame genotypes widely scattered in the Wr-Vr graphical analysis (Figures 1a, 1b, 2a, 2b, 3a, 3b, 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b) for all studied traits under both irrigation regimes, this confirmed their genetic diversity. The most dominant genes were detected in the parents L93, L28 and L95 under NI and L93 under WSC for days to 50% flowering, L92 and L12 under both irrigation regimes for plant height, L93 and L12 under both irrigation regimes for fruiting zone length, L92 and L95 under NI and L92 and L12 under WSC for capsules length, L92 and L12 under NI and L28 and L93 under WSC for number of branches per plant, L93 and L110 under NI and L93 and L92 under WSC for 1000-seed weight, L95 and L93 under NI and L93 and L110 under WSC for seed weight per plant and L93 and L110 under NI and L28 and L93 under WSC, as they located closed to the origin of regression graph. However, the recessive genes were observed in L12 under both irrigation regimes for days to 50% flowering, L110 under both irrigation regimes for plant height, L28 under NI and L92 under WSC for fruiting zone length, L28 under both irrigation regimes for capsules length, L95 under both irrigation regimes Traits I Joint regression analysis Analysis of variance of array Fitness t2 (b) ± SE b=0 b=1 Wr+Vr Wr-Vr Days to 50%flowering N NS 0.12±0.27 NS * ** ** Partially adequate mode S NS -0.09±0.28 NS * ** ** Partially adequate mode Plant height N NS 0.17±0.42 NS NS ** ** Partially adequate mode S NS 0.20±0.41 NS NS ** ** Partially adequate mode Fruiting zone length N NS 0.77±0.31 NS NS ** ** Partially adequate mode S NS 0.33±0.22 NS * ** ** Partially adequate mode Capsules length N NS 0.61±0.27 NS NS ** ** Partially adequate mode S NS 0.21±0.30 NS NS ** ** Partially adequate mode Number of branches per plant N NS 0.50±0.19 NS NS ** ** Partially adequate mode S NS 0.32±0.23 NS * ** ** Partially adequate mode 1000-seed weight N NS 0.18±0.32 NS NS ** ** Partially adequate mode S NS 0.06±0.36 NS NS ** ** Partially adequate mode Seed weight per plant N NS 0.59±0.24 NS NS ** ** Partially adequate mode S NS 0.43±0.28 NS NS NS NS Fully adequate model Seed oil content N NS -0.24±0.25 NS ** ** ** Partially adequate mode S NS 1.06±0.38 * NS ** ** Partially adequate mode Table 11. Adequacy test of the data for additive-dominance model for all studied traits under normal irrigation (N) and water stress conditions (S) in 2019 season Note: I: irrigation regimes; b: Regression-coefficient; Wr: covariance; Vr: variance.*, ** refers to significant at 5% and highly significant at 1%, respectively A. K. Ibrahim Suzan; M. A. Abdelsatar; M. A. Ahmed; M. M. Niazy Peruvian Journal of Agronomy 5(1): 1–17 (2021) 13 for number of branches per plant, L28 under NI and L12 and L95 under WSC for 1000-seed weight, L92 and L110 under NI and L92 and L12 under WSC for seed weight per plant and L12 under NI and L92 under WSC for seed oil content, as they located farthest from the origin of regression graph. This result corroborates with the findings of Fahmy et al. (2015), who found that asymmetrical distribution of dominant and recessive genes in parental genotypes. Parameter I Days to 50% flowering Plant height Fruiting zone length Capsules length Number of branches per plant 1000-seed weight Seed weight per plant Seed oil content D N 8.31 275.78** 88.26** 0.09* 1.02 0.12 21.03** 1.92 S 7.12* 159.51** 20.23 0.04 0.42 0.05 15.80** 3.12** F N 6.29 364.43 -18.74 -0.06 0.89 -0.23 14.19 1.52 S 0.85 191.75 -26.11 0.02 0.71 -0.05 3.74 1.92 H1 N 81.92** 864.57** 446.07** 0.45** 5.70** 1.06** 85.79** 11.60** S 51.08** 515.27** 209.77** 0.30* 3.53** 0.65** 80.76** 16.47** H2 N 64.42** 602.20** 390.38** 0.42** 5.16** 0.97** 75.07** 10.54** S 48.78** 370.19** 185.69** 0.26* 2.97** 0.64** 74.78** 13.14** h2 N 42.16** 378.54* 911.77** 0.69** 13.79** 1.80** 82.34** 3.33 S 21.64** 234.78* 349.31** 0.42** 7.46** 1.11** 129.57** 15.91** (H1/D) 0.5 N 3.14 1.77 2.25 2.22 2.37 2.96 2.02 2.46 S 2.68 1.80 3.22 2.59 2.89 3.67 2.26 2.30 H2/4H1 N 0.20 0.17 0.22 0.23 0.23 0.23 0.22 0.23 S 0.24 0.18 0.22 0.22 0.21 0.24 0.23 0.20 KD/KR N 1.27 2.19 0.91 0.74 1.45 0.51 1.40 1.38 S 1.05 2.00 0.67 1.22 1.81 0.74 1.11 1.31 h2/H2 N 0.65 0.63 2.34 1.66 2.67 1.86 1.10 0.32 S 0.44 0.63 1.88 1.63 2.51 1.73 1.73 1.21 h2 (n.s) N 0.38 0.36 0.45 0.46 0.19 0.47 0.29 0.20 S 0.26 0.37 0.42 0.31 0.14 0.26 0.29 0.39 H2 (b.s) N 0.99 0.99 1.00 0.97 0.94 0.98 0.91 0.91 S 0.99 0.99 0.99 0.95 0.90 0.97 0.88 0.94 Table 12. Components of the genetic variance and their ratios (Hayman 1954b) for all studied traits under normal irrigation (N) and water stress conditions (S) in 2019 season Note: I, irrigation regimes; *, significant when it exceeds 1.96 after dividing it by its standard error; **, is tested by t test at n−2 degrees of freedom after dividing it by its standard error. D = Additive variance, F= Relative frequency of dominant and recessive allels, H1= Dominance variance, H2= Dominance variance, h2= square of difference P vs. all, (H1/D) 0.5= Average degree of dominance, H2/4H1= Proportion of dominance and recessive genes, KD/KR= Proportion between dominant and recessive genes in all parents, h 2/H2= Number of effective factors, h 2 (n.s) = Narrow-sense heritability, H2 (b.s) = Broad-sense heritability Fig. 1a: Wr/Vr graphs for days to 50% flowering under NI Fig. 1b: Wr/Vr graphs for days to 50% flowering under WSC Genetic behavior for seed yield and yield components in sesame (Sesamum indicum L.) under normal irrigation and water stress conditions January - April 2021 14 Fig. 2a: Wr/Vr graphs for plant height under NI Fig. 2b: Wr/Vr graphs for plant height under WSC Fig. 3a: Wr/Vr graphs for fruiting zone length under NI Fig. 3b: Wr/Vr graphs for fruiting zone length under WSC Fig. 4a: Wr/Vr graphs for capsule length under NI Fig. 4b: Wr/Vr graphs for capsule length under WSC A. K. Ibrahim Suzan; M. A. Abdelsatar; M. A. Ahmed; M. M. Niazy Peruvian Journal of Agronomy 5(1): 1–17 (2021) 15 Fig. 5a: Wr/Vr graphs for number of branches per plant under NI Fig. 5b: Wr/Vr graphs for number of branches per plant under WSC Fig. 6a: Wr/Vr graphs for 1000-seed weight under NI Fig. 6b: Wr/Vr graphs for 1000-seed weight under WSC Fig. 7a: Wr/Vr graphs forseed weight per plant under NI Fig. 7b: Wr/Vr graphs forseed weight per plant under WSC Genetic behavior for seed yield and yield components in sesame (Sesamum indicum L.) under normal irrigation and water stress conditions January - April 2021 16 Conclusion In conclusion, the differences due to parents and their F1 crosses were highly significant for seed yield and yield components under both irrigation regimes and their interactions with irrigation. Mean squares of two types of combining ability were highly significant for seed yield and yield components regimes and their interactions with irrigation. The best combiners for seed yield per plant and most of its component were observed in parents L92, L110 and their combination under both irrigation regimes. The additive gene action makes a greater contribution in the inheritance of most studied traits, that further confirmed by its significance and the value of average degree of dominance exceeding the unity. Narrow-sense heritability was high for most studied traits under both irrigation regimes. The most dominant genes carried on L95 and L93 under normal irrigation and L93 and L110 under water stress conditions for seed weight per plant, in contrary L92 and L110 under normal irrigation and L92 and L12 under water stress conditions for seed weight per plant possessed high concentration of recessive genes. References Abd EL-Satar, M. A., Ahmed Fadia, H. A., & Elnenny, E. M. M. (2016). Line × tester analysis of yield and its components for high plant density tolerance in sesame. Egyptian Journal of Plant Breeding, 20(6), 1009–1034. 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