Comparative study to determine stable performance in sweetpotato (Ipomoea batatas [L.] Lam.) regional trials
2002
Manrique, Kurt | Hermann, Michael
Sweetpotato is grown around the world in a wide diversity of environments, often by small farmers in marginal soils, with little inputs. In spite its capability to adapt to harsh growing conditions, sweetpotato is sensitive to environmental variation. Multilocational sweetpotato field trials were conducted to compare efficiency of AMMI model, regression analysis, and Tai’s stability statistics to classify clones based on the stability of their performances. Trials involving 9 sweetpotato clones of diverse origin comprised 14 different environments to investigate GxE interaction effects on root yield and carotene content in roots. Strong agreement was found between AMMI model and Tai’s stability analysis to facilitate classification of clones based on stability of their root yield and carotene content performances. Therefore, both methods may be used jointly to evaluate relative stability of genotypes in regional trials. Tai's statistics give an easy interpretable graphic report on stability of genotypes, and AMMI model provides information on the stability and trends of environments as well as the correlation between a genotype and environment. Regression analysis did not effectively identify clones according to their stability, but does provide information on clone performance under improving growing environments. This study shows that deviation from regression (S2d) and Tai's statistic were satisfactory for selecting desirable clones. Clone JPKY 16.005 was more stable in root yield and carotene content. The lack of association of high root yield and carotene content with stable performance suggest the need for further study to elucidate the nature of high yield performance in response to varying agro-ecological conditions.
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