Genotype × environment interaction and stability analysis of sweetpotato (Ipomoea batatas) genotypes

Nine introductions of sweetpotato (Ipomoea batatas) of diverse origin and two local genotypes were evaluated for storage root yield and average storage root weight in four locations of Turkey (Diyarbakir and Sanliurfa representing semi-arid environment and Adana and Hatay representing Mediterranean environment) in 2000 and 2001. The genotype × environment (GE) interaction was evaluated for two yield components (mean storage root weight and storage root yield) using the joint regression analysis and the Additive Main Effects and Multiplicative Interaction (AMMI) analysis. Stability of the genotypes over environments was estimated by using different stability parameters. GE interaction was found to be significant for both yield components, and genotype main effect contributed more than environment and GE interaction to total variability. Total storage root yield varied from 6.72 to 112.60 t ha-1, depending on genotypes and environments. The introduced genotypes produced a higher yield than local genotypes. Our study revealed that sweetpotato has a great adaptability and yield potential in irrigated Mediterranean-type and semi-arid environments, whereas non-traditional production areas such as Adana, Diyarbakir, and Sanliurfa may be more suitable for sweetpotato production than Hatay, the traditional production area, because of the potential for higher yield. The AMMI model appeared to be a better option for evaluating both GE interaction and the stability of sweetpotato genotypes in multilocational trials. The stability parameters tested in this study could not identify high yielding and stable genotypes. © 2007 Taylor & Francis Group, LLC