A decadal analysis of improved sorghum (Sorghum bicolor) cultivar response to fertilizer application in rainy season and a hypothetical grain production model

Abstract

The multi-location testing methodology was based on the principle of an un-biased approach to identify the best performing product, certified by a multi-disciplinary team and popularized through frontline demonstration programme. The data from one of the mandatory trials were summarized over a decade (1998–2007) to understand the results split over 2 periods (1998 to 2002 and 2003 to 2007) and derive physiological basis of yield enhancement. The results during the first half of the decade indicate that the best performing hybrids attained an increase in yield of 0.7 tonnes/ha as compared to the best performing varieties. The translocation of dry matter produced from leaf and stem into the grain was > 25% in hybrids, while it was approaching 25% in the varieties. Proportional increase in grain yield (due to application of external fertilizer input) over the control was linearly related to the N fertilizer use efficiency. Fertilizer N-use efficiency (DY/DN) defined as change in yield for every unit of applied N increased from 10 kg grain to 20 kg grain/kg of N applied. Hence, increase in productivity can be brought about both by genetic improvement as well as associated nutrient management intervention in a rainfed environment. The hypothesized sorghum static model substantiates the physiological basis of sorghum grain yield.