MEANS AND VARIANCES IN SYNTHETIC MAIZE VARIETIES WITH DIFFERENT GERMPLASM SOURCES OF TEOSINTE

Abstract

Wild relatives of crop species are potential sources for increasing genetic diversity, and thereby for improving the resistance to adverse
environmental factors and grain yield. In the case of teosinte (Zea spp.), the closest relative of maize (Zea mays L.), there are encouraging results for using it to improve maize elite lines; but there is less information about using maize populations containing teosinte germplasm as a potential source in maize improvement. This research was conducted to estimate the effect of six sources of teosinte on population parameters (means and variances) through three generations of recombination. Seven synthetics and their generations F₂, F₃, and F₄ were evaluated in Tlajomulco and Ameca, Jalisco, México, under irrigation and rainfed conditions, respectively. The experiment was
based on a randomized complete block design with four replications, where treatments were arranged as factorial with six teosinte sources and generations F₂, F₃, and F₄ as factors. Means and variances were calculated for each population, and tests for homogeneity of variances were performed to determine whether the observed variances were equal for each treatment. None of the teosinte germplasm sources caused significant increases in grain yield and yield components. The most promising teosinte sources for maize improvement for subtropical areas were JAL (Zea mays ssp. parviglumis) and ZD (Zea diploperennis) because they showed the highest variability and mean values. Although variances between generations and locations were not consistent, teosinte sources were capable to modify positively the genetic variability for some variables, because variances were greater than those obtained for the original synthetic.