Agricultural Science Digest
Chief EditorArvind kumar
Print ISSN 0253-150X
Online ISSN 0976-0547
NAAS Rating 5.52
SJR 0.156
Chief EditorArvind kumar
Print ISSN 0253-150X
Online ISSN 0976-0547
NAAS Rating 5.52
SJR 0.156
Submitted25-11-2019|
Accepted23-04-2020|
First Online 16-05-2020|
Variety adaptability and yield stability
Analysis of variance indicated that specific genotype and environment combinations were significantly (P < 0.01) different (Table 1). The AMMI analysis divided the main effects of treatments into genotype, environment and G × E interactions (Table 1). There were significant (P < 0.01) differences among the components. Environmental effects accounted for 37.13% of the total variation while the genotypes (G) and the G × E interaction accounted for 23.68% and 23.54%, respectively. Anuradha et al., (2017) observed comparable significant results while evaluating 36 soybean genotypes in three environments. The first and second interaction principal component axis (IPCA) explained 18.76% (IPCA1-9.8%; IPCA2-8.96%) of the interaction. The IPCA1 score indicated that about 66% of the genotypes were highly interactive (Table 4). The most interactive genotypes were DPSB 3 (-28.8) and Nyala (17.23). The least interactive genotype based on first IPCA was DPSB 8 (0.49). Genotype by environment interaction makes it difficult for breeders to make genotype selections and variety recommendations Cucolotto et al., (2007). Prediction of performance or selection of elite genotypes based on seed yield is better achieved by use of multi-environment trials Yan et al., (2010). The high yielding genotypes were Nyala, SBH 7/1/1, SBH 1/12/19 and DPSB 8 [Table 4 and Fig 1(a)]. The highest seed yielding genotype (Nyala) was unstable Fig 1(b). Low yielding genotypes (DPSB 3) had high IPCA1 scores (Table 4) and DPSB 19 in Fig 1 (b) denoting that either high yielding or low yielding genotypes maybe unstable. Selection of genotypes based on seed yield may result in selection of unstable genotypes. However, genotypes identified as seed yield stable were medium yielding [Table 4 and Fig 1(b)] with yields 1.8-21.8% higher than the mean yield of 1267 Kg ha-1.
Analysis of variance indicated significant (P < 0.01) genotype differences for their seed oil content across environments (Table 3). The effects due to genotypes, environments and G × E interactions were significant (P < 0.01) among the components. The environment component contributed 52.17% to the total sum of squares while the genotypes contributed 36.57% and the G × E interaction contributed 5.26%. The IPCA1 explained 2.68% of the variation while IPCA 2 explained 1.71%. The mean oil content was highest at Nakuru west (223 g kg-1) and least at Njoro II (179 g kg-1) [Table 2 (b)]. Genotypes SBH 4/4/4, 931/5/34 and Gazelle were the most stable genotypes for oil content based on AMMI analysis and genotypes SBH 4/4/4, Gazelle and SBH 7/1/1 based on GGE biplot analysis [Table 4; Fig 2 (a)]. The choice of stable varieties by both methods of analysis were similar but there were differences in the ranking. Tubic et al., (2011) while evaluating thirteen soybean genotypes observed small differences in oil content stability. Genotype by environment interactions observed in AMMI analysis could be attributed to weather and edaphic factors as was suggested by Tukamuhabwa et al., (2012).
Stability of important soybean yield components. Stability was highest on EAI 3600 on pods plant-1 and least on DPSB 3 [Fig 4 (a)]. The principal components explained 79.68% of the variation in stability among genotypes. Genotype EAI 3600 had highest stability based on 100-seed weight [Fig 4.4 (b)]. The first principal component explained 80.63% of the variation while the second principal component explained 12.09% of the variation in stability of genotypes based on seed weight.
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