Identification of newly developed drought tolerance maize inbred lines under managed field screening

Abstract

Maize is traditionally a kharif season crop in India and nearly 85% maize grown under rainfed area. Drought is one of the major causes of yield reduction in maize among abiotic stresses. Development of high yielding and drought tolerance maize hybrids essentially required heterotic and drought tolerant parental lines in addition to high productivity for drought prone areas. Screening of germplasm under managed abiotic stress field conditions is an efficient way to identify stress tolerant germplasm. Eighty-eight newly developed fixed inbred lines and 12 parental lines of released hybrids were evaluated under normal and drought environment at Regional Maize and Seed Production Centre (ICAR-IIMR), Begusarai during rabi-2020-21. The drought stress was imposed by withholding irrigation for three weeks starting before flowering and continues to grain filling stage. Drought severely affected the reproductive development of plant and seed setting due to widening of anthesis-silking interval (ASI). Kernel test weight was also reduced 12.17% to 27.43% under drought environment. Grain yield was reduced 8.8 % to 38.4% under drought environment. Forty inbred lines showed drought susceptibility index less than unity showing better drought tolerance. On the basis of per se performance and drought susceptibility index eleven inbred lines namely IMLSB 49-2, WNC 72347, IMLSB 301-, IMLSB 1299-5, IMLSB 93-1, IMLSB 591-2 IMLSB 43-2, IMLSB 37-2, IMLSB 2034 and IMLSB 2166 were identified comparatively more drought tolerant. Two inbred lines IMLSB 49-2 and IMLSB 43-2 showed less yield reduction as compared to normal environment and high yield under normal and drought environment. These eleven lines may be utilized for the development of drought tolerant hybrids after estimating combining abilities and heterosis. These inbred lines may also be utilized for constitution of drought tolerant base population following chain crossing for further extraction of next generation drought tolerant inbred lines.