THE GAMETOPHYTE FACTOR 1 (ga1) IN MEXICAN COMMERCIAL HYBRIDS OF MAIZE

Abstract

In this study we determined the allelic composition of the incompatibility locus ga1 (Gametophyte Factor-1), of 84 Mexican maize (Zea mays L.) commercial hybrids planted in tropical, subtropical and highland areas of México, plus seven races of maize with known allelic composition included as checks. P-3394 (ga1/ga1) and the single crosses between tropical and temperate inbreds, NC354 x W22-P4830 and NC354 x W22-P5270 (Ga1-S/Ga1-S), were used as testers. Commercial hybrids were grouped by public or private institution and differences among groups were determined based on ear seed set by means of two procedures, GLM and MIXED from the Statistical Analysis System. Allelic constitution within and among institutions was variable. Most materials were homozygous Ga1- m/Ga1-m (55 %), while about 25 % were homozygous ga1/ga1, and 20% were heterozygous Ga1-m/ga1. Allele Ga1-S was not found in any of the commercial hybrids tested.