ASSESSMENT OF INTER-TRAIT RELATIONSHIP AND IDENTIFICATION OF KEY SELECTION TRAITS FOR DROUGHT TOLERANCE IN MAIZE (ZEA MAYS L.) INBRED LINES UNDER WATER-STRESS CONDITIONS

Abstract

Drought is a major constraint on crop production especially in maize. It significantly reduces productivity, affecting the livelihoods of millions and the overall economy. Malnutrition due to lack of essential nutrients like Vitamin A is another major challenge in many African countries. Breeding for pro-vitamin A drought-tolerant maize varieties is crucial to address these. Knowledge and understanding of interrelationships between grain yield and yield-related traits would ensure progress from selection in maize breeding programs through the use of appropriate selection indices. 107 pro-vitamin A maize inbred lines along with 3 testers were screened for drought tolerance in Samaru and Bagauda in 2020/2021 dry season to assess the relationship between grain yield and yield-related traits. The experiments were laid out in a 10 x 11 alpha lattice design and replicated two times using single-row plot of 5m long.  Inbred lines with high tolerant index values were identified; SLMP-59 has the highest index value (18.06) with a low yield reduction percentage of 38.07% making it the best drought response. The inbred SLMP-3 turns out to be most drought susceptible with drought index value of -12.59 and yield reduction of 83.39% The negative genotypic association of days to pollen (rg = -0.80**) and days to silking (rg = -0.79**) and phenotypic association of days to pollen (rp = -0.97***) and days to silking (rp = -0.98***) with grain yield implies that these traits are not co-inherited together with grain yield and that short anthesis silking interval period would increase grain yield due to the synchronization of pollen shedding and silking emergence. Traits associated with ear aspect are the most reliable traits for indirect selection for grain yield improvement under drought condition.