Combined Half-Sib and S, Recurrent Selection for Drought Tolerance in a Maize (Zea mays L.) Population

Drought is defined as a combination of environmental conditions that results in an internal plant water stress limiting potential growth or yield. Short periods of drought stress are common during the life cycle of maize in rainfed production areas, and such periods are decisive in reducing yield. Biological immunity to the effects of drought is not a possibility. However, through plant breeding, it may be possible to develop some degree of tolerance to the effects of drought. One strategy for developing drought tolerant maize genotypes is to select under moisture stress conditions. However, drought is normally an uncertain condition, varying in its incidence, severity, and timing. This suggests the need to select for performance in both well-watered and moisture-stressed environments. A procedure that gradually increases the frequency of desirable alleles in base populations, while maintaining genetic variability is recurrent selection. Several studies have shown that recurrent selection methods have been effective for increasing grain yield of maize {Sprague and Eberhart, 1977). In 1980, a project was initiated to develop a population tolerant to drought stress by using a combined half-sib and S1 recurrent selection approach. The objective of the present study was to evaluate the response of the first two cycles of this population by looking at gains from selection and stability parameters