EVALUATION OF THREE GRAIN MAIZE COMPOSITES DEVELOPED FROM BROAD-BASE SYNTHETICS BY DIVERGENT SELECTION ON THREE COMPLEMENTARY TESTERS

摘要

Three composites, FC(TC)CO, FC(TD)CO and FC(TI)CO, were developed from S1 families with good general combining ability, derived from broad-base maize synthetics. These synthetics were developed by the INRA (Institut national de la recherche agronomique) maize laboratory of Montpellier from inbred lines belonging to different heterotic groups. The idea was to develop new heterotic groups. Composite development is the initial phase of a recurrent selection program. The grain productivity of the composites (yield, grain moisture and lodging resistance) and their genetic divergence were evaluated in both diallel and topcross designs. In crosses with testers, the yields of composites were on average 11-14 q/ha less than that of commercial checks with a comparable grain moisture, and they were more susceptible to lodging. Heterosis for yield between composites was low. This low divergence is consistent with the constitution procedure of the composite, based mainly on the general combining ability.