ASSESSMENT OF GROUNDNUT CULTIVARS FOR END-OF-SEASON DROUGHT TOLERANCE IN A SAHELIAN ENVIRONMENT

A 2-year study (1990 and 1991) was conducted at the ICRISAT (International Crops Research Institute for the Semi-Arid Tropics) Sahelian Centre, near Niamey, Niger, to select groundnut cultivars tolerant to drought and to examine selection techniques. Thirty-six cultivars known to vary in yield potential were grown under rainfed and irrigated conditions. Crop growth rate (C) and partitioning co-efficient (p) were estimated from phenological and final harvest data. The correlation between years was greater for partitioning than for pod yield (implying a higher heritability for p than for yield). Tolerance as determined by a drought susceptibility index for pod yield (S-Y), crop growth rate (S-C) and partitioning (S-p) to reproductive sinks showed thirteen cultivars as drought tolerant for either C or p or for both. The Sahelian cultivars 796, 55-437 and TS 32-1 were the most consistent for drought tolerance. Partitioning was the most important yield component affecting yield variation among cultivars.