Gene action conditioning phosphorus utilization in tropical maize.

Abstract

Maize (Zea mays L.) is an important economic crop on the African continent. However, its production is constrained by both abiotic and biotic factors. Among the abiotic stresses phosphorus (P) deficiency is one of the major constraints affecting maize productivity. The objective of this study was therefore to investigate the type of gene action conditioning phosphorus utilization in P-limited soils. Thirteen, previously screened inbred lines with varying performances relative to phosphorus utilization in P-limited soils, were mated according to North Carolina Design II (NCD II) (8 females × 5 males). Forty (40) progenies were evaluated in a screen house using a completely randomized design (CRD), with three replications, and two levels of P (0 kg P and 60 kg P). Shoot biomass, root biomass, plant biomass and plant height were measured after the plants were harvested and dried at 80 o C for 72 h. Specific combining ability (SCA) was found to be highly significant (P < 0.001) for all measured traits. General combining ability (GCA) was significant only for root biomass (P = 0.05). The Baker’s ratio for plant height, shoot biomass, root biomass and plant biomass was 0.12, 0.15, 0.49 and 0.28, respectively, indicating that predominantly non- additive gene action conditioned all parameters, except root biomass, where both additive and non-additive gene action were found to be important.