1Central Potato Research Station, Modipuram-250 110, (U.P.).
2Central Potato Research Institute, Shimla-171001, (H.P.).
Twenty two advance stage hybrtds and six commercial potato varteties were evaluated for yield performance at 60, 70, 80 and 90 days harvest for 3 years (1991–94) at Modipuram. The varieties differed genetically in their regression on environmental index. The proportion of E (linear) was substantially higher than V×E (linear). In early harvest (at 60 and 70 days) the culture MS/82–797 gave the highest yield (467 g/plant), regression coefficient (b = 1.04) close to 1 and a non significant deviation from regression. In the medium group (at 80 and 90 days) culture JEX/C-166 gave the highest yield (660 g/plant), regression above 1 (b=1.70) and non-significant deviation from regression. Culture MS/82–797 was found suitable to replace both Kufri Chandramukhi and Kufri Bahar in early crop and JEX/C-166 and MS/82–797 to replace Kufri Bahar and Kufri Badshah in the main crop in western Uttar Pradesh.
