Impaginato 359 Adv. Hort. Sci., 2019 33(3): 359-364 DOI: 10.13128/ahs-23992 Biometry and vigor of seeds of Myrciaria dubia (Kunth) McVaugh C.R. do Nascimento 1 (*), E.A. Chagas 2, O.J. Smiderle 2, A. de Andrade Souza 1, P. Cardoso Chagas 1 1 Federal University of Roraima, UFRR, Campus Cauamé, BR 174, Km 12, Monte Cristo, 69300‐000, Boa Vista, RR, Brazil. 2 Brasilian Agricultural Research Corporation, Embrapa Roraima, Caixa Postal 133, 69301‐970 Boa Vista, RR, Brazil. Key words: biometric characterization, camu-camu, class size, fruit growing, rate of emergency, water content. Abstract: Camu-camu has aroused the interest of various industries like natural preservatives, ice creams, juices, jellies, wines, natural dyes, but there is little technical information about the seeds. The objective of this work was to determine the biometric, physical and vigor characteristics of camu-camu seeds. Seeds originating from native populations of Roraima were used. The biometry was determined and the data were analyzed in Excel spreadsheet and calculated the mean, median, variance, standard deviation and seeds classified as small, medium and large, based on mass. The vigor was determined by electrical conductivity, seedling emergence, emergence velocity, plant height, stem diameter, in a completely causal design, with four replicates of 25 seeds. The average results for width, thickness, length, individual mass, volume, weight of one thousand seeds and number of seeds per kilogram showed large variability. The size of the seed has direct correlation with vigor, large seeds have greater vigor. 1. Introduction The camu-camu, Myrciaria dubia (Kunth) McVaugh, is a small fruit tree of the Myrtaceae family, popularly known as araçá-dágua, azedinho, camocamo and caçari (Smiderle and Sousa, 2008). It occurs naturally in the Amazon region, growing naturally along the banks of rivers, streams, channels and lakes (Chagas et al., 2012; Souza et al., 2017). The fruit of the camu-camu is used in the preparation of juices, jellies, alcoholic drinks and ice creams, among others (Yuyama, 2011; Sousa et al., 2013). The main property of the camu-camu is the high vitamin C content, around 6,112 ± 137.5 ascorbic acid 100 g-1 of pulp, better than most cultivated plants (Yuyama, 2011). The skin of the camu-camu when fresh contains high levels of anthocyanin and ascorbic acid (Villanueva-Tiburcio et al., 2010). The interest aroused by the camu-camu is due to its bioactive com- pounds and biological activity of antioxidant action, which reduce lipid peroxidation, revert high levels of total cholesterol and triacylglycerols, and increase the levels of HDL-cholesterol (Gonçalves, 2012). (*) Corresponding author: nascimentocr0@gmail.com Citation: DO NASCIMENTO C.R., CHAGAS E.A., SMIDERLE O.J., DE ANDRADE SOUZA A., CARDOSO CHAGAS P., 2019 - Biometric characteristics of camu‐camu seeds from native populations in the State of Roraima, classified by size class. - Adv. Hort. Sci., 33(3): 359-364 Copyright: © 2019 do Nascimento C.R., Chagas E.A., Smiderle O.J., de Andrade Souza A., Cardoso Chagas P. This is an open access, peer reviewed article published by Firenze University Press (http://www.fupress.net/index.php/ahs/) and distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant data are within the paper and its Supporting Information files. Competing Interests: The authors declare no competing interests. Received for publication 24 September 2018 Accepted for publication 23 April 2019 AHS Advances in Horticultural Science http://creativecommons.org/licenses/by/4.0/ http://creativecommons.org/licenses/by/4.0/ http://creativecommons.org/licenses/by/4.0/ Adv. Hort. Sci., 2019 33(3): 359-364 360 Seed characteristics are important in the study of any species, as they give an understanding of the dis- persion and establishment of seedlings. The classifi- cation of seeds by size or weight is a strategy to be adopted in the standardisation and emergence of seedlings, and to obtain seedlings of similar size or greater vigour (Carvalho and Nakagawa, 2012). Therefore, the biometry of fruits and seeds have a diagnostic value in differentiating species within a genus, and can contribute to their recognition (Pereira and Ferreira, 2017). In order to find the ideal size class for the multipli- cation of different plant species, biometry is used to determine physiological quality, but the results have differed considerably, even when the seeds are from the same species. Biruel et al. (2010) found that larg- er seeds of Caesalpinia leiostachya displayed a greater percentage and speed of germination; differ- ent results to those reported by Queiroga et al. (2011), who studied peanut seeds and found that smaller seeds had a higher germination percentage. Seeds of different sizes showed the same high germination percentage, with small seeds being the most viable, and medium and large seeds yielding seedlings that were more vigorous (Vendramin and Carvalho, 2013; Smiderle et al., 2016). This ambiguous situation may be one of the rea- sons for two or more seed sizes being produced by the same species. Variations in size were seen in seeds collected in an area of natural occurrence in the State of Roraima, Brazil. In view of the above, the aim of this work was to determine the biometry, physical characteristics and vigour of seeds of the camu-camu. 2. Materials and Methods The experiment was carried out at the Seed Analysis Laboratory of Embrapa Roraima. The camu- camu fruit used in the experiment were harvested from native plants located on the banks of the Jatapú River (0° 41.072” N and 59° 18.046” W) at an altitude of 144 m. Here the plants develop in rocky soil in the district of Caroebe in the State of Roraima, and are distributed along the river in various populations and subpopulations. After harvesting, the fruits were packed in plastic bags to prevent damage from crushing, and carefully transported to the laboratory, where they were select- ed for lack of damage, and then homogenised and sanitised. The mature selected fruit were then depulped and washed in running water, using a sieve for the complete removal of any pulp adhering to the seeds. Physical characterisation of the seeds The seeds were evaluated for their physical charac- teristics. Seed biometry. The individual thickness, length and width of 600 seeds were measured using a calliper, with the results expressed in mm. The length was measured along the longitudinal axis of the seed; the width was measured perpendicular to the length, con- sidering the broad face of the seed, which corresponds to the median line; and the thickness, by again mea- suring perpendicular to the length, but on the smaller seed face, corresponding to the median line including the two cotyledons. The following were then obtained: Seed volume (mm3): multiplying the three dimen- sions (width, length and thickness), without consider- ing the actual shape of the seed. Individual seed weight: obtained by weighing each seed. Based on these measurements, the seeds were separated into three size classes (large, medium and small). 1000 seed weight (g). Six samples of 100 seeds were used for each size class. The samples were weighed on a 0.001 g precision balance and the weight determined by multiplying the result by 10. Number of seeds per kilogram. After determining the thousand-seed weight (TSW), the number of seeds per kilogram was calculated using the “rule of three”. Water content (%). Carried out using the standard oven method at 105±3°C for 24 hours. Four replica- tions of 10 seeds were used, where each sample was wrapped in aluminium and placed in an oven. After 24 hours, the samples were removed from the oven and placed in a desiccator for cooling, and then weighed on a 0.001 g precision balance. The water content was calculated based on the difference between the wet and dry weights, applying the formula proposed in the Rules for Seed Analysis (MAPA, 2009), with the result expressed as a percentage. The biometric data were analysed in an Excel spreadsheet. The mean, median, variance and stan- dard deviation were all calculated. Determining the vigour of small, medium and large seeds of the camu‐camu The experiment was carried out in a greenhouse at Embrapa Roraima, in Boa Vista. The experimental design was completely randomised (CRD), with three treatments comprising the size classes (small, medi- Do Nascimento et al. ‐ Seeds biometry and vigor of Camu‐camu 361 um and large), and four replications of 25 seeds. Seeds with a weight between 0.66 g and 0.84 g were considered small, those with a weight between 0.92 g and 1.20 g were considered medium, and those with a weight between 1.27 g and 1.60 g considered large. After classification, the following analyses were carried out: Electric conductivity (EC). the seeds were weighed on a 0.0001 g precision balance and then immersed in 75 mL of water for 24 hours at a constant temper- ature of 25°C. The electrical conductivity was then measured using a digital conductivimeter. The results were expressed in μS cm-1 g-1 of seed. Seedling emergence. The test was carried out fol- lowing procedures described in the Rules for Seed Analysis (MAPA, 2009). The tests were conducted in trays containing 50% sand + 50% sawdust as sub- strate moistened with water up to 60% of its reten- tion capacity, using four replications of 25 seeds dis- tributed at a depth of 2.0 cm. The test was per- formed in a nursery of 50% Sombrite shade screen. To evaluate the non-germinated seeds, they were removed from the substrate, cut down the middle with pruning shears and identified for viability and senescence. The formula used for calculation was: E = (N/A) x 100: Where E = percentage emergence; N = number of emerged seedlings; A = total number of seeds placed for emergence. Speed of seedling emergence. Established by means of a daily count of emerged seedlings, the index being calculated from the expression: SE = (E1/N1) + (E2/N2) + ... + (En/Nn), where: SE = speed of seedling emergence; E1 = number of seedlings emerged at the first count; N1 = number of days elapsed until the first count; E2 = number of seedlings emerged at the second count; N2 = number of days elapsed until the second count; n = last count. Plant height. Evaluated four months after sowing with the aid of a graduated rule (cm). Measured from the cotyledon node to the end of the first pair of leaves in normal seedlings identified at the end of the test for seedling emergence. Stem diameter. Evaluated four months after sow- ing using a digital calliper (mm). Determined at the insertion of the cotyledon. The data for water content, electrical conductivi- ty, seedling emergence, speed of emergence, plant height and stem diameter were submitted to the Lilliefors test for normality. They were then submit- ted to analysis of variance (ANOVA), using a com- pletely randomised design with four replications, and the mean values compared by Tukey’s test at 5% probability using the SISVAR software (Ferreira, 2014). 3. Results and Discussion From the results, it was seen that there was a sig- nificant difference in the biometric variables of the analysed seeds, and it was possible to separate them into three classes according to size: small, medium and large. The data for variance, standard deviation and coefficient of variation, and the mean results for individual weight, width, thickness, length and volume of the camu-camu seeds are shown in Table 1. The biometric data shown indicates that the stud- ied population was accurately sampled, since the val- ues for variance were low (<1) for each of the charac- teristics under study. The values for standard devia- tion shown in Table 1 indicate a low sample variation for each of the characteristics under evaluation. The values for the coefficient of variation demon- strate the low variation in the variables, considering the mean value of the characteristics. However, vari- ation can be seen when the seeds are sorted by size. Table 1 - Biometric characteristics of camu-camu seeds from native populations in the State of Roraima, classified by size class Class Mean Variance Standard deviation Coefficient of variation (%) Weight (g) Small 0.79 0.002 0.04 5.65 Medium 1.11 0.004 0.06 5.90 Large 1.45 0.008 0.08 6.12 Width (mm) Small 12.04 0.541 0.73 6.11 Medium 12.90 0.147 0.38 2.97 Large 14.42 0.233 0.48 3.34 Thickness (mm) Small 5.54 0.065 0.25 4.59 Medium 6.11 0.213 0.46 7.56 Large 6.74 0.329 0.57 8.51 Length (mm) Small 15.54 0.620 0.79 5.07 Medium 17.42 0.206 0.45 2.61 Large 19.14 0.342 0.58 3.05 Volume (mm3) Small 1,035.77 6,144.378 78.38 7.57 Medium 1,371.98 6,104.830 78.13 5.69 Large 1,859.47 20,759.298 144.08 7.75 Adv. Hort. Sci., 2019 33(3): 359-364 362 Similar results were found in camu-camu seeds from the banks of the Anauá River in Roraima, with a weight which ranged from 0.80 g to 1.46 g, and greater results than the seeds of populations from the Rio Urubu, which ranged from 0.56 to 0.78 g (Souza et al., 2017). According to Gonçalves et al. (2008), species with wide geographic distribution may present differences in their characteristics due to the effects of adaptation and to origin. The variation in seed size may interfere with their physiological quality, still poorly researched in forest species (Oliveira et al., 2009; Smiderle et al., 2016). The three classes of seed size displayed significant differences for thousand-seed weight (TSW) and the number of seeds per kilo (NSK) with a low coefficient of variation, showing little variation within each size (Table 2). The initial water content of the seeds in the differ- ent size classes at the time the experiment was set up was greater than 35%, with significant differences between the classes (Table 3), however it was lower than that reported by Yuyama et al. (2011), who obtained a value for moisture between 45 and 56%, with no effect on germination. According to Braga et al. (2012), hydration of the seeds can favour test per- formance, because seeds that are more humid, with- in certain limits, germinate more quickly. The different classes of seed displayed variations in the variables under analysis. It was found that val- ues for electrical conductivity depend on the size of the seed, where the large, small and medium seeds presented higher, lower and intermediate physiologi- cal quality respectively (Table 3). According to Vieira and Krzyzanowski (1999), the lower physiological potential in small seeds is probably due to the lower organisational intensity of the cell-membrane sys- tems. The data for electrical conductivity in the small seeds showed a negative correlation with the other variables under study, demonstrating that the high- est value for electrical conductivity corresponded to reductions in the percentage and speed of seedling emergence. These results confirm those reported by Vinhal-Freitas et al. (2011), and demonstrate that tests of vigour differentiate between seed classes, indicating significant differences between the larger and smaller size classes, where larger seeds showed greater vigour with the smallest values for electrical conductivity. With the large seeds, the lower value for electrical conductivity was due to a greater organisation of the cell components, since, despite field emergence not differing statistically from that of the small seeds, they showed greater speed of emergence in addition to viability, even when not germinated, as the small seeds that did not emerge had all died. It is important to point out that despite the differ- ences seen in electrical conductivity between the seed sizes, each seed class had low values for EC, and values for emergence that were higher than the mini- Table 2 - Summary of the analysis of variance and comparison of the mean values for thousand-seed weight (TSW) and number of seeds per kilo (NSK) in camu-camu seeds from native populations in the State of Roraima, classified by size * significant at 5% probability by F-test. Mean values followed by the same letter do not differ by Tukey’s test at 5% probability. * significant at 5% probability by F-test. Table 3 - Summary of the analysis of variance and comparison of mean values for water content (WC, %), electrical conductivity (EC, μS cm-1 g-1), emergence (EMERG, %), speed of emergence, (SE, index), seedling height (HT S, cm) and stem diameter (DIAM S, mm) in camu-camu seeds classified by size Source of variation DF Mean square TSW NSK Treatment 2 346,622.68* 435,142.53* Replication 5 633.44 672.57 Error 10 1,610,651.55 1,318.23 CV (%) 4.16 3.35 Overall mean value 963.88 1,082.76 Class Mean value Small 734.27g 1.362 Medium 943.67 g 1.061 Large 1,213.70 g 825 Source of variation DF Mean square WC (%) EC μS cm-1 g-1 EMERG (%) SE HT S (cm) DIAM S (mm) Treatment 2 14.67* 1.83* 433.33* 0.021* 79.12* 0.599* Replication 3 0.08 0.002 5.55 0.000008 0.131 0.0012 Error 6 0.29 0.001 5.55 0.000008 0.049 0.0008 Mean 37.17 3.27 88.33 0.056 15.61 2.13 CV (%) 1.46 1.11 2.67 5.17 1.42 1.36 Class Mean values Small 35.35 c 3.95 c 80 b 0.01 c 11.30 c 1.71 c Medium 36.99 b 3.22 b 100 a 0.03 b 15.34 b 2.20 b Large 39.17 a 2.61 a 85 b 0.14 a 20.18 a 2.48 a Do Nascimento et al. ‐ Seeds biometry and vigor of Camu‐camu 363 dência de sementes de ‘Mimosa caesalpiniifolia’ Benth., sobre a germinação e vigor. ‐ Revista Árvore, 29(6): 877-885. BIRUEL R.P., PAULA R.C., AGUIAR I.B., 2010 - Germinação de sementes de ‘Caesalpinia leiostachya’ (Benth.) Ducke (pau‐ferro) classificadas pelo tamanho e pela forma. ‐ Revista Árvore, 34(2): 197-204. BRAGA N.S., MORAIS C.S.B., ROSSETTO C.A.V., 2012 - Hidratação controlada de sementes de pinhão manso. - Revista Ciência Agronômica, 43(3): 589-597. CARVALHO N.M., NAKAGAWA J., 2012 - Sementes: Ciência, tecnologia e produção. 5th edition. ‐ Jaboticabal: FUNEP, pp. 590. CHAGAS E.A., LIMA C.G.B., CARVALHO A.S., RIBEIRO M.I.G., SAKAZAKI R.T., NEVES L.C., 2012 - Propagação do camu‐camu (‘Myrciaria dubia’) (H.B.K.) McVaugh). - Revista Agro@mbiente On-line, 6(1): 67-72. FERREIRA D.F., 2014 - Sisvar: a guide for its bootstrap pro‐ c e d u r e s i n m u l ti p l e c o m p a r i s o n s . ‐ C i ê n c i a e Agrotecnologia, 38(2): 109-112. GONÇALVES A.E.S.S., 2012 - Compostos bioativos do camu‐ camu (‘Myrciaria dubia’ McVaugh): caracterização e atividade biologica. - Tese Doutorado, Universidade de São Paulo, Brazil, pp. 114. GONÇALVES J.V.S., ALBRECHT J.M.F., SOARES T.S., TITON M., 2008 - Caracterização física e avaliação da pré‐ embebição na germinação de sementes de sucupira‐ preta (‘Bowdichia virgilioides’ KUNTH). ‐ Cerne, 14(4): 330-334. M A P A , 2 0 0 9 - R e g r a s p a r a a n á l i s e s d e s e m e n t e s . - Ministério da Agricultura, Pecuária e Abastecimento, Secretaria de Defesa Agropecuária, Brasília, DF, Brazil, pp. 399. OLIVEIRA A.B., MEDEIROS-FILHO S., BEZERRA A.M.E., BRUNO R.L.A., 2009 - Emergência de plântulas de ‘Copernicia hospita’ Martius em função do tamanho da s e m e n t e , d o s u b s t r a t o e d o a m b i e n t e . ‐ R e v i s t a Brasileira de Sementes, 31(1): 281-287. PEREIRA S.A., FERREIRA S.A.N., 2017 - Fruit and seed biom‐ etry and seedling morphology of ‘Parkia discolor’ (Spruce ex Benth.). ‐ Revista Árvore, 41(2): 1-8. QUEIROGA V P., FREIRE R.M.M., ARAUJO M.E.R., LIMA V.I., QUEIROGA D.A.N., 2011 - Influência do tamanho da semente de amendoim sobre sua qualidade fisiológica. ‐ Revista Agro@mbiente On-line, 5(1): 30-34. SILVA A.C.D., SMIDERLE O.J., OLIVEIRA J.M.F., SILVA T.J., 2017 - Tamanho da semente e substratos na produção de mudas de açaí. - Adv. For. Sci., 4: 151-156. SMIDERLE O.J., SOUSA R.C.P., 2008 - Teor de vitamina C e características físicas do camu‐camu em dois estádios de maturação ‐ Revista Agro@mbiente On-line, 2(2): 61-63. SMIDERLE O.J., SOUZA A.G., ALMEIDA M.S., SOUZA A.A., 2016 - Caracterização biometrica e superação de dor‐ mencia de sementes de biribá no crescimento inicial de seedlings. - Revista Congrega URCAMP (CD-ROM), 1: 23-34 mum established by the Seed Standards (MAPA, 2009). As for plant height and stem diameter, the larger seeds promoted the best results, followed by the medium and small seeds respectively. There was a positive correlation between seed size and plant height and stem diameter, i.e. larger seeds gave rise to larger, more vigorous plants. These results differ from those obtained by Souza et al. (2017), who reported that seeds from a population of the Anauá River considered small, displayed better results for these characteristics. Wagner Junior et al. (2011) demonstrated that seed size has an effect on the emergence and initial development of jabuticaba seedlings (Plinia cauliflo‐ ra), and that large seeds gave seedlings that were more vigorous. In açaí Silva et al. (2017) in organic substrate obtained higher values for plant height and stem diameter when large seeds were used, as well a s . l a r g e s e e d s p r o d u c e m o r e v i g o r o u s p l a n t s independent of the substrate in Euterpe oleracea. Alves et al. (2005) pointed out that in general, larger seeds are correlated with higher rates of initial seedling growth, which increases the probability of success during their establishment, since the rapid growth of roots and shoots allows the plant to take advantage of the nutrient and water reserves of the soil and carry out photosynthesis. Wagner Junior et al. (2011) stated that the germination process in m a n y s p e c i e s i s i n fl u e n c e d b y s e e d s i z e . Consequently, within the same batch, small seeds present lower seedling emergence and less vigour than the medium and large seeds. 4. Conclusions The physical characterisation of camu-camu seeds shows great variability in weight, width, thickness, length and volume. The thousand-seed weight and the water content are influenced by size, with values increasing in direct proportion to the size of the seed, while the number of seeds per kilo decreases in inverse proportion. Medium and large seeds give rise to plants that are more vigorous. References ALVES E.U., BRUNO R.L.A., OLIVEIRA A.P., ALVES A.U., PAULA R.C., 2005 - Influência do tamanho e da proce‐ 364 Adv. Hort. Sci., 2019 33(3): 359-364 SOUSA R.C.P., SANTOS D.C., NEVES L.T.B.C., CHAGAS E.A., 2013 - Tecnologia de bioprocesso para produção de ali‐ mentos funcionais. - Revista Agro@mbiente On-line, 7(3): 366-372. SOUZA O.M., SMIDERLE O.J., SOUZA A.G., CHAGAS E.A., CHAGAS P.C., BACELARLIMA C.G., MORAIS B.S., 2017 - Influência do tamanho da semente na germinação e vigor de plântulas de populações de camu‐camu ‐ Scientia Agropecuaria, 8(2): 119-125. VENDRAMIN D.W., CARVALHO R.I.N., 2013 - Qualidade fisiológica de sementes de pitangueira (‘Eugenia uniflo- ra’ (L.) (Myrtaceae). ‐ Estudos Biologicos, 35(84): 59-65. VIEIRA R.D., KRZYZANOSWSKI F.C., 1999 - Teste de conduti‐ vidade elétrica, pp. 1-26. - In: KRZYZANOSWSKI F.C., R.D. VIEIRA, and J.B. FRANÇA NETO, (eds.) Vigor de sementes: conceitos e testes. ABRATES, Londrina, Brasil, pp. 218. V I L L A N U E V A - T I B U R C I O J . E . , C O N D E Z O - H O Y O S L . A . , ASQUIERI E.R., 2010 - Antocianinas, ácido ascórbico, polifenoles totales y actividad antioxidante, en la cás‐ c a r a d e c a m u ‐ c a m u ( ‘ M y r c i a r i a d u b i a ’ ( H . B . K ) McVaugh). - Ciências e Tecnologia de Alimentos, 30(Supl.1): 151-160. VINHAL-FREITAS I.C., GARCIA JUNIOR J.E., SEGUNDO J.P., VILARINHO M.S., 2011 - Germinação e vigor de semen‐ tes de soja classificadas em diferentes tamanhos. - Agropecuaria Técnica, 32(1): 108-114 WAGNER JÚNIOR A., SILVA J.O.C., PIMENTEL L.D., SANTOS C.E.M., BRUCKNER C.H., 2011 - Germinação e desenvol‐ vimento inicial de duas espécies de jabuticabeira em função do tamanho de sementes. - Acta Scientiarum Agronomy, 33(1): 105-109. YUYAMA K., 2011 - A cultura de camu‐camu no Brasil. ‐ Revista Brasileira de Fruticultura, 33(2): 335-690. Y U Y A M A K . , M E N D E S N . B . , V A L E N T E J . P . , 2 0 1 1 - Longevidade de sementes de camu‐camu submetidas a diferentes ambientes e formas de conservação. ‐ Revista Brasileira de Fruticultura, 33(2): 601-607.