©Haramaya University, 2022 ISSN 1993-8195 (Online), ISSN 1992-0407(Print) East African Journal of Sciences (2022) Volume 16(1): 93–100 Licensed under a Creative Commons *Corresponding author: desta.ab12@gmail.com Attribution-NonCommercial 4.0 International License. Registration of ‘Pawe-2’ Rice Variety for Upland Ecosystem in Ethiopia Desta Abebe1*, Mulugeta Atnaf2, Gedifew Gebrie1, Abebaw Dessie2, Desalegn Wondifraw1, Mulugeta Bitew4, Atsedemariyam Tewachew2, Yeshiwas Sendekie1, Desalegn Teshale1 Tesfaye Gudisa1, and Zeynu Tahir3 1Pawe Agricultural Research Center, P.O. Box25, Pawe, Ethiopia 2Fogera National Rice Research and Training Center, P.O. Box 190, Wereta, Ethiopia 3Gondar Agricultural Research Center, P.O. Box 1337, Gondar, Ethiopia 4Debre Markos Agricultural Research Center, P.O. Box 357, Debre Markos, Ethiopia Abstract Background: Rice (Oryza sativa L.) is produced in Ethiopia. However, the national average yield is far below the potential of the crop due to, among others, limited availability of stable, high yielding and disease tolerant upland rice varieties. This problem has seriously limited production of the crop in the country. Objective: The research was conducted to evaluate and release a stable high yielding and disease resistant/tolerant upland rice varieties for the typical upland rice ecosystems in Ethiopia. Material and Methods: The rice variety (currently named Pawe-2) introduced from Brazil in 2012 was evaluated along with NERICA-4 and Fogera-1 as local and standard check varieties, respectively, at Pawe and Metema (typical upland rice ecosystems) beginning from a 2013. After the evaluation of the variety for six years, verification trials were conducted in 2019 and in 2020. Results: Pawe-2 had better performances for most agronomic traits than the check varieties. The newly released variety, ‘Pawe-2’ had an average grain yield of 5058.93 kg ha–1, and it had yield advantages of 15.68% and 13.52% over Fogera-1 and NERICA-4 rice varieties, respectively, as shown by the results of the verification trails conducted in 2019. Moreover, Pawe-2 had a higher biomass yield, larger grain size, white caryopsis color, early maturity and resistance to diseases and pests than the check varieties. Conclusions: It is concluded that the variety ‘Pawe-2’ is superior to the other varieties in terms of yield, yield stability, and resistance to pests and diseases. Therefore, the National Variety Release Committee approved Pawe-2 for cultivation in the mid altitude (750–1800 meters above sea level) and similar typical upland rice ecosystems in Ethiopia. Keywords: Early maturing; Grain yield; Upland rice variety; Verification and yield advantage 1. Introduction Rice (Oryza sativa L.) is a cereal commonly used as a staple food crop for a significant part of human population. It provides 27% of the calories in the world’s low and middle-income countries (Fukagawa and Ziska, 2019). The rice production system is classified into lowland and upland rice. In lowland rice, fields are usually flooded during part or all of the growing season; lowland rice includes rain-fed lowland, irrigated lowland, deep-water and mangrove swamp (Saito et al., 2013). Upland rice grows on level or sloping, unbunded fields and flooding is rare in this system. In some cases, especially in Latin America, supplemental irrigation may be used. Upland rice is grown under crop rotation systems with other crops, or under slash-and-burn systems (Atlin et al., 2006; Pinheiro et al., 2006; Saito et al., 2006). Recent statistics from 71 countries from Asia, Latin America, and sub- Saharan Africa show that lowland and upland rice account mailto:desta.ab12@gmail.com Desta et al. East African Journal of Sciences Volume 16(1): 93–100 94 for 92 and 8% of total rice cultivation area, respectively (Saito et al., 2018). Rice is one of the most strategic crops in Africa, and particularly in Ethiopia (Meron Abebe, 2016). Ethiopia has immense potential for growing rice. In 2019/20 Meher season, 178,185 households produced rice on 57,575.72 hectares of land and produced a total of 170, 630.1 tons with average yield of 2.964 t ha–1. The total area cultivated for rice has reduced by 9.13%, but the total yield has reduced only by 0.71% and the national average yield has increased by 0.252 ton (9.29%) than 2018/19 main production season (CSA, 2020). The increase of average national yield with a one-season change seems showing the productivity of the crop is fast growing, but it is still low as compared to its potential. This is due to biotic and abiotic stress including limited number of varieties available to withstand major biotic and abiotic stress. In this regard, Pawe and Metema agricultural research centers have been working on the development of upland rice varieties with high yield potential, early maturity and resistance to major rice diseases (blast, brown spot, sheath blight, bacterial panicle blight and sheath spot) and pests (Taye Tadesse et al., 2019). Evaluation of introduced rice varieties and available genotypes over locations and seasons is one the breeding methods to develop high yielding upland rice varieties in Ethiopia. Accordingly, the introduced variety from Brazil in 2012 was evaluated along with the existing rice varieties over locations and seasons to test the cultivation value of the variety in Ethiopia. The introduced variety was found to be superior to the existing rice varieties for yield and other desirable agronomic traits and approved for cultivation by the National Variety Release Committee in 2020 named as Pawe-2 upland rice variety. This paper presents the overall performances of the recently released upland rice variety (Pawe-2) aiming at providing information for all actors in rice production in Ethiopia. Evaluation of introduced rice varieties and available genotypes over locations and seasons is one the breeding methods to develop high yielding upland rice varieties in Ethiopia. Accordingly, the introduced variety from Brazil in 2012 along with the existing rice varieties was evaluated over locations and seasons to test its cultivation value in Ethiopia. The introduced variety was found to be superior over the existing rice varieties for yield and other desirable agronomic traits and approved for cultivation by the National Variety Release Committee in 2020 named as Pawe-2 upland rice variety. This paper presents the overall performances of the recently released upland rice variety (Pawe-2) aiming to provide information for all actors involved in rice production in the country. 2. Varietal Evaluation Three varieties having unique characters like high grain yield, long grain size, early maturity, and disease and pest resistance were introduced from Brazil in 2012. The varieties are commercially cultivated in Brazil. The three introduced varieties and two standard check varieties, NERICA-3 and NERICA-4 were evaluated during 2013 to 2015 main cropping seasons in northwestern Ethiopia specifically at PARC (Pawe Agricultural Research Center). During a preliminary yield evaluation trial, PARC.DAT.V-3.2013 was identified as a candidate variety (Pawe-2) since it outperformed the standard check varieties and other two introduced varieties. The candidate variety and other genotypes, a total of 17 genotypes were advanced to national variety trial and evaluated across locations for two years. The standard check was NERICA-4 released in 2006 in Ethiopia. The genotypes were evaluated at major upland rice growing areas, namely, Fogera (Woreta), Gondar (Metema), Pawe, Assosa (Kamashi), and Shire (Mai-tsebri) for two years (2016/2017 to 2017/2018) in a randomized complete block design (RCBD) with three replications. In 2018/2019 cropping season, PARC.DAT.V-1.2013 as candidate variety-1 and PARC.DAT.V-3.2013 as candidate variety-2 (Pawe-2) along with NERICA-4 and Fogera-1 as local and standard check varieties, respectively, were evaluated for verification at seven test sites. The National Variety Release Committee evaluated the varieties on the field. Pawe-2 consistently outyielded the other tested rice varieties over three years. The average yield of Pawe-2 was 5033.01kg ha–1 in 2013 up to 2015 main cropping seasons (Table 1). Combined years over locations analysis revealed that Pawe-2 produced an average yield of 4984.50 kg ha–1 during 2016–2017 cropping season (Table 3). Pawe-2 also showed superior overall agronomic performances over the standard check (Fogera-1) and the local check (NERICA-4) varieties under verification trial. Likewise, it proved to be more resistant for leaf blast, panicle blast, and brown spot; and scored less damage by different insects like termite and stalk eye fly than the check varieties. The results of the over locations and seasons revealed that, Pawe-2 was superior in grain yield performance, protein content, and diseases resistance. Thus, the recommendation of Pawe-2 for cultivation was reasonable and it is important to register as a commercial Desta et al. Registration of ‘Pawe-2’ Rice Variety Ethiopia 95 variety to promote its production in typical upland rice ecosystems. In the same manner, Girma Mengistu et al. (2013) were evaluated the pipeline upland rice genotypes against the standard check viz., Superica-1, across six environments during the 2012 main cropping seasons and the variety “Chewaka” showed superior performance over the other pipelines and recommended by the National Variety Released Committee to be registered as a variety. Similarly, Famoso et al. (2019) reported the Registration of ‘PVL01’ Rice as evaluated the rice genotypes across seven environments for resistance to Provisia herbicide, containing the active ingredient quizalofop, an AACase (group 1) herbicide. 3. Agronomic and Morphological Characters Pawe-2 showed a higher number of tillers per plant, a larger number of field grain per panicle, larger-sized seeds, higher grain yield and better resistance to diseases and pests than the standard check (Fogera-1) during the variety verification trial. Pawe-2 is distinguished by a white seed color and long seed size, and thousand-grain weight of 12.34 grams. It attained 50% heading, 50% heading, 50% flowering, and 85% maturity in 80, 84 and 118 days, respectively, after emergence. It had panicle length of 21.09 cm and plant height of 97.51 cm (Tables 4 and 5) with the average number of fertile tillers per plant of 6.4. Harrell et al. (2021) reported the registration of different rice varieties following similar research methods and the rice varieties registered had a higher number of tillers per plant, a larger number of field grain per panicle, larger- sized seeds, a higher grain yield and better resistance to different rice diseases. 4. Yield Performance Pawe-2 was produced a higher average mean grain yield (5033.01 kg ha–1) than NERICA-4 (4405.02 kg ha–1) and NERICA-3 (4305 kg ha–1) during the three years (2013– 2015) evaluation (Table 1). Pawe-2 had a higher yield advantage of 14.26% and 16.89% over NERICA-4 and NERICA-3 varieties, respectively. It also produced a higher grain yield than the standard check (Fogera-1) and local check (NERICA-4) during the variety verification trial in 2018/2019 main cropping season at seven sites (Table 4). Pawe-2 variety had a higher biological yield (55414.29 kg ha–1) than the two check varieties Fogera-1 (44214.29 kg ha-1) and NERICA-4 (43996.67kg ha–1) (Table 4). Consistent with these results, Harrell et al. (2021) reported the registration of different rice varieties that had higher yield advantages than the standard and the local checks as tested in more year and seasons. 5. Reaction to Pest and Disease Pawe-2 was superior in tolerance to diseases (leaf blast, panicle blast and brown spot) and sustained less termite and shoot fly damage compared to the check varieties (Fogera-1 and NERICA-4). Significantly lower termite damage of 21% was recorded to Pawe-2 than the Fogera- 1 (43%) and NERICA-4(50%) check varieties (Tables 2 and 4), and in 2018/2019 cropping season, the four genotypes did not show any symptoms of the disease. Consistent with this result, Harrell et al. (2021) reported similar findings. Rice leaf blast (Magnaporthe grisea) is a key concern in combating global food security given the disease is responsible for approximately 30% of rice production losses globally-the equivalent of feeding 60 million people (Nalley et al., 2016). These losses increase the global rice price and reduce consumer welfare and food security. Even, rice brown spot (Helminthosporium oryzae) is a chronic disease that affects millions of hectares of rice every growing season, grown by some of the most resource-poor farmers. Brown spot is conventionally perceived as a secondary problem that affects rice crops that experience physiological stresses, e.g., drought and poor soil fertility, rather than a true infectious disease (Barnwal et al., 2013). Therefore, BS is by far one the strongest yield reducers amongst rice diseases today. The range of reported yield losses to BS, often expressed in relative terms, is variable from 26 to 52% (Chakrabarti, 2001). Desta et al. East African Journal of Sciences Volume 16(1): 93–100 96 Table 1. Combined mean grain yield and other agronomic traits for upland rice genotypes in Pawe at two locations over three years (2013–2015). S/N Variety DH DM PH (cm) PL (cm) FTP FGP GY (kg ha–1) TSW(g) 1 PARC DAT-V1-2013 78.21 113.11 90.54 22.16 9.52 145.58 4838.16 26.15 2 PARC DAT-V2-2013 81.5 111.15 91.50 23.26 8.51 139.65 4715.56 26.01 3 PARC DAT-V-3-2013 82.5 114.20 87.08 23.05 8.05 143.48 5033.01 25.90 4 NERICA-3 73.5 112.5 82.5 21.25 7.15 135.8 4305.5 24.8 5 NERICA-4 (Check) 71.23 109.00 84.30 21.15 8.45 137.78 4405.02 25.00 Mean 77.388 111.992 87.184 22.174 8.336 140.458 4659.45 25.572 Maximum 82.5 114.2 91.5 23.26 9.52 145.58 5033.01 26.15 Minimum 71.23 109 82.5 21.15 7.15 135.8 4305.5 24.8 Note: DH = Days to 50% heading; DM = Days to 85% maturity; PL = Panicle length (cm); PH = Plant height (cm); FTP = Fertile tillers/plant; FGP = Filled grains/panicle; GY = Grain yield (kg ha–1); and TSW (g) = Thousand seed weight. Table 2. Mean values of different diseases reaction scores (0–9) of the genotypes in Pawe at two locations over three years (2013–2015). S/N Variety Leaf rust Panicle blast Brown spot Sheath rot Termite damage (%) Seedling Tillering Dough Maturity Tillering Milk stage 1 PARC DAT-V1-2013 0 0 1 0 0 0 0 2.0 2 PARC DAT-V2-2013 0 0 0 0 1 0 1 1.6 3 PARC DAT-V-3-2013 0 0 0 1 0 0 0 1.5 4 NERICA-3 1 1 0 0 1 1 0 4.5 5 NERICA-4 (Check) 1 0 0 0 0 0 0 3.5 Note: 0 = Highly resistant and 1 = Resistance reactions. Desta et al. Registration of ‘Pawe-2’ Rice Variety Ethiopia 97 Table 3. Combined mean grain yield and other yield related parameters of 17 upland rice genotypes during 2016-2017cropping season. S/N Genotypes (G) Code DH DM PH PL FTP FGP GY (kg ha–1) 1 NM1-29-4-B-P-80-8 G1 73 101 93.04 21.38 5.85 130.14 4845.50 2 ART16-9-29-12-1-1-2-B-1-1 G2 73 101 102.77 20.91 6.78 120.79 3965.60 3 ART16-9-14-16-2-2-1-B-1-2 G3 69 98 93.96 22.24 5.98 117.46 4745.80 4 ART16-9-33-2-1-1-1-B-1-2 G4 77 104 98.87 21.13 6.23 127.92 4834.30 5 ART16-9-122-33-2-1-1-B-1-1 G5 75 102 97.90 20.73 6.74 117.33 4885.80 6 ART15-19-5-4-1-1-1-B-1-1 G6 75 102 96.28 21.34 6.10 110.43 4658.00 7 ART16-5-9-22-2-1-1-B-1-2 G7 76 102 95.27 19.99 6.20 126.85 5027.20 8 ART16-21-4-7-2-2-2-B-2-2 G8 73 101 94.46 20.95 6.14 125.79 4717.90 9 ART16-9-16-21-1-2-1-B-1-1 G9 76 101 102.07 21.64 5.87 114.26 4902.50 10 ART15-13-2-2-2-1-1-B-1-2 G10 73 99 92.54 21.61 6.49 114.47 3762.10 11 ART15-16-45-1-B-1-1-B-1-2 G11 74 101 96.56 21.53 5.86 189.89 4398.60 12 ART16-5-10-2-3-B-1-B-1-1 G12 75 101 102.30 21.98 6.19 122.80 4603.20 13 ART16-4-1-21-2-B-2-B-1-2 G13 76 103 97.12 21.23 6.19 130.41 4516.80 14 PARC.DAT.V-1.2013 G14 78 104 97.64 21.37 7.12 131.74 4528.00 15 PARC.DAT.V-2.2013 G15 79 104 99.68 22.14 7.00 125.19 4207.40 16 PARC.DAT.V-3.2013 G16 79 106 99.29 21.92 6.02 129.73 4984.50 17 NERICA-4(Check) G17 72 101 93.09 20.56 6.99 124.67 4712.70 Mean 74.80 101.85 97.26 21.32 6.36 126.42 4617.88 CV (%) 3.76 2.19 7.93 7.92 23.63 27.21 16.67 LSD (5%) 1.97 1.57 5.41 1.18 1.05 24.12 539.91 Genotype (G) *** *** *** ** NS NS *** Environment (E) *** *** *** *** *** *** *** Genotype x Environment (G x E) NS NS NS NS NS NS ** Note: DH = Days to 50% heading; DM = Days to 85% heading; PL = Panicle length (cm); PH = Plant height (cm); FTP = Number of fertile tillers per plant; FGP = Number of filled grains per panicle; and GY = Grain yield (kg ha–1). ** and *** refer to significant level at P < 0.01 and 0.001, respectively, and NS = not significant at P < 0.05. Desta et al. East African Journal of Sciences Volume 16(1): 93–100 98 Table 4. Mean grain yield, other agronomic traits and diseases reaction of PARC.DAT.V-1.2013 (candidate-1), PARC.DAT.V-3.2013, Pawe-2 (candidate-2) and the check varieties during multi-location evaluation in 2019/2020. Traits Candidate-1 Candidate-2 NERICA-4 Fogera-1 Days to 50% heading 81.57 80.43 71.86 72.00 Days to 50% flowering 85.43 84.14 75.14 75.14 Days to 85% maturity 121.57 117.86 106.14 105.00 Plant height (cm) 94.84 97.51 87.00 89.66 Panicle length (cm) 20.31 21.09 19.66 19.57 Number of fertile tillers/plants 6.03 6.40 4.83 4.71 Number of unfertile tillers/plants 0.06 0.11 0.20 0.14 Number of filled grain/panicles 147.53 152.17 137.06 140.8 Number of unfilled grain/panicles 4.60 4.59 4.11 3.91 Grain yield (kg ha–1) 4727.50 5058.93 4456.24 4372.9 1000 seed weight 12.07 12.34 11.36 11.53 Moisture content 27.79 28.04 26.79 26.86 Stand count 670571.43 731714.29 600857.14 624857.14 Biological yield (kg ha–1) 51885.71 55414.29 43996.67 44214.29 Termite damage (%) 0.21 0.21 0.50 0.43 Leaf blast at seedling 0.00 0.00 0.00 0.00 Leaf blast at tillering 0.00 0.00 0.00 0.00 Panicle blast at dough stage 0.00 0.00 0.00 0.00 Panicle blast at maturity stage 0.00 0.00 0.00 0.00 Brown spot at tillering 0.00 0.00 0.00 0.00 Brown spot at milk stage 0.00 0.00 0.00 0.00 Sheath rot 0.00 0.00 0.00 0.00 Table 5. Morpho-agronomic characteristics of Pawe-2 upland rice variety. Variable Description Variety name: Pawe-2 Agronomic and morphological characteristics: Adaptation area Pawe, Fogera, Assosa, Gondar, Maitsebri and other similar agro- ecologies of Ethiopia. • Altitude (m.a.s.l.) a 750–1860 • Rainfall (mm) 1100–1457 Seed rate (kg ha–1) 60 Planting date mid-June to early July depending on the onset of rainfall Spacing(cm) 25 cm between rows for row drill planting Fertilizer rate (kg ha–1) and time of application N = 69 (1/3 at planting, 1/3 at tillering and 1/3 at panicle initiation) and P2O5 = 23 (all at planting) Days to heading 80 Days to maturity 118 Panicle length(cm) 21.1 Plant height(cm) 97.5 Thresh ability Easy Lodging incidence None Shattering Moderately Resistant Seed size(mm) Slender shape [length (9.2): width (2.5) =7.14] Growth habit Erect No. of grains per panicle 152 1000 seed weight (g) 12.34 Caryopsis color White Crop pest reaction Resistant to major rice diseases Grain yield (kg ha–1) Research field 5059 Farmers field 4847 Year of release 2020 Breeder/maintainer: Pawe Agricultural Research Center /EIAR Note: a m.a.s.l. = meters above sea level. Desta et al. Registration of ‘Pawe-2’ Rice Variety Ethiopia 99 6. Other Quality Traits In the major rice-consuming countries, grain quality characteristics dictate the market value of the commodity and play an important role in the development and adoption of new varieties. Grain quality includes such traits as physical appearance and nutritional values. The rice varieties were mainly developed based on yield and other desirable traits. However, Pawe-2 contains has also good nutritional values like protein, fat and ash, and better market-oriented variety than the tested genotypes. The average kernel length of the variety was higher than other tested varieties with a higher protein content (4.79%) (Atsedemariyam Tewachew et al., 2018). 7. Conclusion The results of this study have demonstrated that Pawe-2 is a high yielding variety, resistant to major rice diseases such as blast and brown spot. Moreover, the variety has a greater number of tillers per plant, a greater number of filled grains per plant, longer grains and white caryopsis color. Its grain is also relatively rich in protein, ash and fat. Generally, the variety has traits preferred by farmers as confirmed by their positive feedback during the evaluation and verification trials. Hence, it is necessary to promote the variety in typical upland rice growing areas of Ethiopia. 8. Acknowledgements The authors thank the Ethiopian Institute of Agricultural Research for providing financial supports to evaluate and release the variety and Fogera National Rice Research and Training Centre for cooperating and coordinating the evaluation trials across locations. The authors also appreciate the technical staff of rice improvement program of Pawe, Fogera, Gondar-Metema Research Centers for smooth implementation of the trials over the years. 9. 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