Sorghum mutation breeding for tolerance to water deficit under climate change

This study aimed at creating genetic variability by induced mutagenesis in farmers’ preferred sorghum variety (ICSV1049) to breed mutant lines for water deficit tolerance. Sorghum seeds were irradiated by gamma rays and sown as one panicle-to-one progeny method. Putative lines M5 (143) and parent were screened under water deficit stress. Data analysis showed that leaf senescence (LS) was positively correlated to relative water content (RWC), panicle weight (PaWt), grain weight (GrWt) and chlorophyll content 13 days after water deficit application (SPAD II). Semi-dwarf trait (SDwf) with plants height (Ht)<100 cm were observed among 3.38% of lines, while 13.5% exhibited early maturity (<90 days). The leaves of 87.3% of lines were semi-erectile. Averaged overall lines, mutation has reduced date to flowering (DaFl), date to grain maturity (DaMa) and LS at 9.2, 4.1 and 8.1% compared to the parent, respectively. However, SPAD I (chlorophyll content first day of water deficit application), SPAD II, RWC, GrWt, PaWt and Ht were increased at 30.8, 40.5, 36.5, 22.2, 37.5 and 9.3%, respectively. Based on the results, seven mutant lines exhibited tolerance to water deficit. Key words: Mutagenesis, genetic variability, drought-tolerance.