Enhancing Maize Grain Yield in Acid Soils of Western Kenya Using Aluminium Tolerant Germplasm

Abstract

Abstract: Maize (Zea mays L.) is one of the world’s most important cereals and is a staple food for many people in developing countries. However, in acid soils (pH < 5.5), its productivity is limited by aluminium (Al) toxicity, besides other factors. The objectives of this study were to: develop Al tolerant maize inbred lines for a maize breeding program in Kenya, develop single cross hybrids (SCHs) from some of the tolerant inbred lines and determine Al tolerance levels of the SCHs. One hundred and seventy five inbreds and 49 SCHs were developed and screened in nutrient culture containing 0 or 222 μM using Relative Net Root Growth (RNRG), hematoxylin staining (HS) and under Al saturated field conditions (44%-45.6%) at Sega and Chepkoilel. Seedling root growth was inhibited in 95% of the inbreds. F1 hybrids obtained from inbreds varying in Al tolerance, exhibited tolerance equal to or greater than that of the more tolerant parent indicating a positive transgressive inheritance to Al toxicity. Fifty eight percent of the F1 SCHs were heterotic for tolerance to Al toxicity. Al tolerance estimated by RNRG was well correlated to that of HS (r2 = 0.88, P < 0.005) but minimally correlated with the field estimates (r2 = 0.24-0.35), implying that RNRG can predict field selection under Al toxic soils by between 24% and 35%. Plant breeders should therefore employ both approaches in selecting cultivars under Al stress. This study has developed and identified Al tolerant inbreds and SCHs for use in the acid soils of Kenya and similar regions.