Introgression of temperate germplasm to improve an elite tropical maize population

The effect of introgression of temperate germplasm into an elite tropical maize population, EV8443SR, was studied for different traits. Two temperate lines, FS14 and DEA, were crossed with EV8443SR. The F1 of each cross was backcrossed to EV8443SR to produce the BC1. F1 and BC1 were subjected to two cycles of random mating. Random sets of S1 families were derived from the tropical-temperate populations and the tropical parent for evaluation in two tropical locations. Introgression of FS14 and DEA into EV8443SR significantly increased earliness, and reduced plant height, number of grains per ear, 1000 grains weight and grain yield. Significant harvest index increases were observed. The effect of introgression on genetic variance of EV8443SR varied with trait and sometimes with cross and location. The highest expected genetic progress was obtained in a tropical-temperate population for most of the traits studied. EV8443SR appeared better than, or pratically equal to, the tropical-temperate populations as a foundation population to improve grain yield and husk cover. This revised version was published online in July 2006 with corrections to the Cover Date.