NATURAL OUTCROSSING RATES OF COMMON BEAN IN CENTRAL HIGH VALLEYS OF MEXICO

Abstract

To assess the influence of location and planting date on the outcrossing rate of dry bean (Phaseolus vulgaris L.), a set of experiments was carried out in 1993 and 1994, at two locations of the Central High Valleys of Mexico. Hypocotyl color was used as genetic marker. The study involved the selection of 10 varieties with green hypocotyl and four with purple hypocotyl; the estimation of outcrossing capability, in four identical experiments grown in both Montecillo and Tecámac, México, in April 24 and May 26, in 1993 and the outcrossing rates assessment was based on the number of seedling with purple hypocotyl found in the F₁ progenies of green hypocotyl varieties. The results showed statiscal significance (p ≤ 0.05) for location, planting date and varieties, as well as for the interactions of planting date with position and varieties, and the varieties x location x planting date interaction. Outcrossing was significatively higher in Tecámac (0.54 %) than in Montecillo, and in April 24 was significantly higher (0.52 %) than for May 26. The 10 varieties showed some degree of natural crossing; however, indeterminated varieties, such as Bayo Mecentral, Bayo Gordo and Manzano, showed the highest outcrossing rates, 4.19, 3.53, and 3.17 %, respectively. Growth habit, and both flowering time and
period were the most important varietal traits associated with the capability of natural outcrossing. The genotype x environment interactions were very important, mostly those related with planting date.