COMBINING ABILITY IN MAIZE LINES USING A DIALLEL CROSS

Abstract

The objective was to select maize (Zea mays L.) lines, based on the effects of general combining ability (GCA), specific combining ability (SCA) and heterosis, for the formation of single crosses. During the spring-summer 2008 cycle, 120 single crosses with the combination of 16 lines of white grain maize were evaluated. To estimate the GCA and SCA effects, the method IV, model I of Griffing's method, was used, in an alpha lattice design with two 16 x 8 repetitions. The results revealed that there are lines with good GCA: LRB-14RC2-1-1, LT-154RC2-1-2, LT-155RC2-1-1, VS-536RC2-1-1, VS-536RC2-1-1, CML-264Q and CML-159. The crosses LT-155RC2-1-1xVS-536RC2-1-1, CABGRC2-1-3xD-539RC2-1-1 and D-539RC2-1-1xCML-159 showed the greatest effects of SCA. Of the inbred lines evaluated, LRB-14RC2-1-1, LT-154RC2-1-2, LT-155RC2-1-1, VS-536RC2-1-1, VS-536RC2-1-1, FAM. V-537C, CML-264Q and CML-159 showed the greatest varietal effect values, considering that there is greater additive gene action and that formation of synthetic varieties is possible. The crosses LT155RC2-1-1xVS536RC2-1-1, CABGRC2-1-3xD-539RC2-1-1 and D-539RC2-1-1xCML-159 showed high ACE effects and high heterosis levels, adequate for the formation of maize hybrids. The use of diallel designs to estimate GCA and SCA in inbred lines and their crosses allowed knowing the most efficient breeding method.