Evaluation of indices for identification of pearl millet cultivars adaptedto stress and non-stress conditions

Pearl millet (Pennisetum glaucum) is cultivated across a wide range of envi ronments ranging from extremely stressful to favourable. The objective of t his research was to compare methods to identify productive cultivars for st ress and non-stress conditions. Thirty pearl millet cultivars were evaluate d at 22 locations that were grouped as stress, non-stress, or intermediate environments. Five selection indices viz., arithmetic mean (AM), geometric mean (GM), AM (standard units), stress susceptibility index (S) and drought response index (DRI) were calculated for each genotype to determine correl ation between selection indices and yield under stress (Y-S), non-stress (Y -NS), and average conditions (Y-AV) Both cultivars and locations were signi ficant sources of variation. Phenology of cultivars had different influence on yielding ability in contrasting environments. While earliness was advan tageous for stress conditions, cultivars with longer duration tended to yie ld more under non-stress conditions. Y-S was only moderately determined by Y-NS Both AM and GM were suitable indices for selection of cultivars that w ould perform well across stress, non-stress, and intermediate environments. Stress susceptibility index (S) was negatively correlated with Y-S (r = -0 .62**) but should only be used as a selection criterion in combination with yield under stress (Y-S) to identify cultivars adapted to stress environme nts. DRI was positively correlated with Y-S but had no association with Y-N S. Results indicated that DRI might be useful for identifying cultivars wit h high performance under stress particularly when days to Bower differ cons iderably among test entries. (C) 2001 Elsevier Science B.V. All rights rese rved.