Physiological characterization of Sorghum [(Sorghum bicolor L.) Moench] germplasm accessions for drought related parameters

Abstract

Sorghum [Sorghum bicolor (L.) Moench] is a C4 plant making it better adapted to high temperature, water deficit and elevated CO2 concentration in the atmosphere.It is the fifth most important cereal after rice, wheat, maize and barley at world level. It is used as food, feed, fodder and biofuel. Major growing states are Maharashtra, Karnataka, AP, MP, Rajasthan & Tamil Nadu. Despite of several efforts, the expected genetic gain in this crop has not been achieved so far. Systematic studies in terms of understanding the physiological bases of the yield and its attributing traits helps in achieving better genetic gains. Sorghum faces moisture stress in a post rainy growing situation making it non remunerative to the farming community. In this context, the present investigation was carried out at Centre on Rabi sorghum (ICAR-IIMR), Solapur to get insight into the drought related physiological parameters. The study consists of 74 sorghum germplasm accessions, grown in RCBD with two replications. The variability in seven physiological traits [Relative water content, chlorophyll content, Specific leaf area, specific leaf weight, SPAD chlorophyll meter reading, Leaf Area Index, Canopy temperature difference] was studied. Study revealed that, there is a significant difference between accessions for most of the physiological traits. Maximum variation was found in chlorophyll b (CV = 55.6) followed by chlorophyll a (CV =31.8), SLW (CV = 25) and SPAD (CV = 18.7). LAI (range = 5.2-10.86), CTD (range = -1.27-10.83°c) and SLW (range= 0.18-0.73mg/cm2), these lines with better physiological traits and higher grain yield can be utilized further as donors in breeding program to isolate superior varieties/ genotypes for drought tolerance in a post-rainy situation