Stability analysis for yield in sweetpotato (Ipomoea batatas) genotypes with special reference to orange-fleshed sweetpotato

Field studies were conducted to assess the relative performance of recently introduced orange-fleshed sweetpotato genotypes [Ipomoea batatas (L.) Lam.] (OFSPs) in comparison with the commonly cultivated white-fleshed genotypes (WFSP). The study used six genotypes (four OFSPs and two WFSPs) across three locations, namely Bhubaneswar (experimental station), Chanabahal and Lausahi (farmer's fields), for two consecutive years (2005-06 and 2006-07) during both rainy (kharif) and winter (rabi) seasons. Storage yields of sweetpotato were affected by the genotypes, locations and seasons. The interaction effects were significant for genotype x season and genotype x location. Yields of the improved WFSP genotype, CIP-SWA-3 were high at all locations. Among the OFSPs, IB-97-2/5 and IB-97-6/15 were on par with CIP-SWA 3, but only in two out of three locations. Among the locations, yields were consistently and significantly higher at Lausahi in both the seasons and years. This was attributed to prevailing relatively lower temperatures at Lausahi. Between the growing seasons, higher yield were observed in rabi than in kharif season. The adaptability of sweetpotato genotypes across environments was also assessed using pooled stability analysis for root yield. Based on the marker values for stability parameters namely, bi=0 (regression coefficient), S(2)di =1 (deviation from regression) and R-2 (coefficient of determination), only one genotype IB-97-6/15 (OFSP) was found to be stable across environments.