PHOTOPERIOD RESPONSE OF BEAN SEGREGATING FAMILIES OF HIGH YIELD POTENTIAL

Abstract

In common bean, genotypes of neutral response to photoperiod show adaptation to different latitudes, whereas sensible genotypes are best adapted to high altitude sites, such as the Mexican Highlands. The photoperiod response of ten F⁶ families, derived from bean genotypes of contrasting photoperiod response and selected on the basis of high yield potential, was determined in the field at Zacatepec, Morelos during the winter cycle of 1996/1997 and in the field and green house at Chapingo, México in 1996 and 1997 (five environments). In the field, a random complete block design with three replicates was utilized. In the field, plants were grown under normal 13.2 h photoperiod and in the greenhouse, two day lengths were used, 8 and 18 h. Flowering data in the greenhouse were used to calculate the rate of development to flower and then this was utilized to calculate the photoperiod sensitivity index. Nine families and the cv. Carioca were photoperiod insensitive, and only the family (PV x C)- 6 and cvs. Pinto Villa and Tlaxcala 475 were sensitive. The families (PV x C)-3, (PV x C)-5, (C x T)-8 y (C x T)-10, all neutral to photoperiod, showed the highest yield in the field, ranging from 277 to 302 g m^-2. In contrast, cv. Tlaxcala 475 and the family (PV x C)-6, both sensible to photoperiod, displayed the lowest yield , 128 and 213 g ^m-2, respectively. Neutral families resulted more stable in the number of days to Flowering and seed yield than sensitive families.