Yield stability of photoperiod sensitive sorghum (Sorghum bicolor L. Moench) accessions under diverse climatic environments

Abstract

Climate variability is a characteristic feature of the tropics where the summer monsoon starts from May/June and ends mostly in October, thus producing an unpredictably variable length of growing season. This results in serious challenges for the mainly substituent small holder farmers in the arid to semi-arid zones of the tropics. A study was conducted to determine the attainable grain yield and yield stability of 10 well characterized and extensively cultivated tropical sorghum accessions across 18 environments comprised of 3 dates of sowing at 3 sites (along a latitudinal gradient covering 3 agro-ecological zones) over 2 years in Mah. For each year and site combination, sorghum accessions and dates of sowing were arranged in a split plot and tested in a Randomized Complete Block (RCB) design. Appropriate cultural practices and timing were used to minimize effects of biotic factors. In addition to Grain yield, yield penalty associated with delayed sowing was determined. Two static and five dynamic indices were used to assess the stability of grain yield for genotypes across environments. Mean grain yield ranged from 0 to 248 g m-2 across environments, from 74 to 208 g m-2 across the 10 genotypes and generally reduced with delayed sowing. A genotype combining photoperiod sensitivity and stay-green traits was revealed as the most stable. The similarities and differences were observed among the stability indices used in terms of ranking of the genotypes. Implications of these for adaptation to climate change are discussed. © 2012 Academic Journals Inc.