Abstract

The need to accelerate breeding for increased yield and better adaptation to drought is an issue of great concern because of the high demand for food and potential climate change poses further challenges. The study was designed to introgress drought-tolerant possessing genes/quantitative trait loci into popular and farmer-preferred cultivars through marker-assisted backcrossing (MABC) and assess for post-flowering drought tolerance. Sixty-one converted progeny and nine parental lines were evaluated under post-flowering water stress condition. The mean grain yield of genotypes that widely varied (923 to 4585 kg ha-1) was 1991 kg ha-1. Out of the 61 BC2F3, 9.8% were superior in yield ranging from 2831 to 4585 t ha-1, indicating the potential to withstand post-flowering moisture stress. They were also characterized by high chlorophyll content, greater leaf area and greenness at physiological maturity. Relatively high heritability (34.8-74.7%) and genetic gain (1.4-42.7%) were obtained for most agronomic and physiological characters, revealing selection for such characters could be easily attained. Thus, the presence of more green leaves, greater green leaf area and high chlorophyll content both at booting and maturity could contribute to higher photosynthesis and better availability of food reserves for grain-filling and improved yield.

Key words: Drought tolerance, introgression, post-flowering, Sorghum bicolor, water-limited.