Genetic Dissection of Low-N Traits using Triple Test Cross Analysis in Maize (Zea mays L.)

Abstract

Low-N maize is bred for its ability to tolerate low soil nitrogen (N) by growing and producing grain that compares appreciably to conventional varieties. This experiment was conducted to study the genetic effects of grain yield and other agronomic traits in Low-N maize using triple test cross analysis. Twelve low-N open pollinated maize varieties were converted to the inbred line after six generations of selfing and used for the experiment. Two inbred lines along with their F₁ were used as testers for ten inbred lines in a triple test cross pattern to generate 30 crosses and along with their parents and testers to make a total of 43 entries which were evaluated at the Teaching and Research Farms of Ekiti State University, Ado-Ekiti during in 2017. The design was a Randomized Complete Block Design (RCBD). Data was collected on plant height, ear height, days to 50% anthesis, days to 50% silking, the incidence of Curvularia leaf spot, blight, plant aspect, ear aspect, ear rot, stay green, cob per plant, ear weight, grain moisture content and grain yield. All data was subjected to analysis of variance and complete genetic estimates made. Additive and dominants were significant (P<0.05) for all traits, however, epitasis estimates were not significant for all the traits. The degree of dominance component indicated partial dominance for all the traits. Correlation coefficients for days to 50% anthesis and 50% silking, plant height, ear height, number of cob per plant and grain yield were positive and significant (P<0.05). Since both additive and dominance gene actions were important for low-N traits, the use of reciprocal recurrent selection procedure can be adopted in incorporating the trait into elite maize varieties.