INTERVARIETAL CROSSES, AN ALTERNATIVE FOR INCREASING YELLOW MAIZE (Zea mays L.) PRODUCTION IN VARIABLE ENVIRONMENTS

In Mexico, maize (Zea mays L.) is grown under rainfed conditions within immensurable number of variable environments that limit production. To cope with these adversities, genotypes of different genetic constitution have been generated, such as intervarietal crosses; however, knowledge of the yield potential of those crosses in variable environments is limited. The objective of the study was to determine the yield potential of intervarietal crosses of yellow maize in environments of high-valley lands in central Mexico, as well as the components that influence yield under the hypothesis that intervarietal crosses are equal in yield to conventional hybrids. Crosses, open-pollinated parental varieties and commercial controls were evaluated in a randomized complete block design. Fifteen agronomic variables and yield components were measured. A combined analysis of variance and comparison of means (Tukey, p <= 0.05) were applied, and Pearson's correlation coefficients were calculated. The analysis of variance detected statistical differences in all the factors of variation in most of the evaluated variables. The intervarietal crosses performed statistically equal to the controls but superior to the parents. The crosses excelled in ear diameter and ear length, total weight of grains in the ear, 100-grain weight, grain length, grain width, plant height, ear height, shelling corn coefficient and prolificacy index. In 23 crosses, the genotype x environment interaction effect was not significant. Intervarietal crosses have yield potential compared to conventional hybrids. Ear and grain traits had the greatest influence on yield. Intervarietal crosses represent an alternative to increase yield and production of yellow maize in the high-valley lands of central Mexico.