HETEROSIS AND GENE ACTION OF DIALLEL CROSS AMONG INBRED LINES OF MAIZE

Abstract

A field experimental were carried out at the field of the Crop Department College of Agriculture-Baghdad University for two seasons, spring and autumn 2012 in order to estimate the heterosis and gene action for diallel crosses which hybridized under two levels of nitrogen 100 and 400 Kg.ha-1. In the first seasonat the diallel crosses were conducted between four inbred lines of maize are Zm7, Zm607, Oh40 and Zr8 to produces six crosses at each level nitrogen .carried out at the autumn season, 2012 using the hybrid trait was RCBD in three replicates with 400 Kg N.ha-1. Gave the cross Oh40×Zm607 higher heterosis in tasseling and silking under 400N and 100 N Kg.ha-1(-11.26% and -9.08%) and (-10.05% and -9.52%) respectively and gave the same cross under 400N Kg.ha-1 highest heterosis reducing plant height and chlorophyll index (19.48% and 12.71%) respectively. The higher heterosis in leaves area was (24.52% and 23.27%) for cross Zm607×Zm7 under 400N and 100N Kg.ha-1. Dominance variance was great than additive variance in characters studies and the average degree of dominance was greater from one except leaves area under 100N Kg.ha-1. The highest values of broad sense heritability were recorded in tasseling and decline narrow sense heritability except leaves area for crosses 100N. We conclude that all characters studies of diallel crosses hybrids under two levels of nitrogen under the control of non-additive gene action, the studied characters can improve using hybridization.