SEED YIELD AND MORPHOLOGICAL TRAITS RELATED TO ERECT PLANT TYPE IN IRRIGATED COMMON BEAN

Abstract

Direct harvest of common bean (Phaseolus vulgaris L.) is feasible, for that plants of erect growth habit are needed. A trial with 64 commercial bean genotypes was conducted during the Fall- Winter season 2004 - 2005. Tested genotypes including five commercial classes: ‘Yellow’, ‘Pinto’, ‘Flor de Mayo’, ‘Flor de Junio’ and ‘Black’, and three growth habits: determinate (type I) and indeterminate (types II and III). The trials were established under irrigated conditions at Los Mochis, in Sinaloa, Celaya, in Guanajuato and Cotaxtla, in Veracruz, México. A triple lattice design 8 x 8 was utilized and the experimental plot was a single 6-m row, with rows separated at 0.8 m. During the growth cycle seven characteristics were recorded: two related to plant phenology, four to plant height structure, plus seed yield. For seed yield there were significant differences (P > 0.05) among sites and genotypes and for the genotype by site interaction. In Los Mochis seed yield varied from 1076 to 2534 kg ha^-1, in Cotaxtla from 700 to 2276 kg ha^-1 and in Celaya from 800 to 4610 kg ha^-1. This large variation observed in yield was the result of the wide diversity among genotypes regarding their origin and growth habit, which resulted in differences in adaptation. On all sites indeterminate genotypes of growth habit types II and III gave higher yields than determinate genotypes type I. The studied morphological traits resulted interrelated among themselves, height to the first pod, plant lodging, physiological maturity and hypocotyl thickness; the higher the first pod, the later to mature and thicker hypocotyls, whereas the lower the first pod, the higher plant lodging. None of these traits was related to seed yield. Under the utilized production system the genotypes of erect plant type displayed low yield; among them, those with high yield were: A 525, ‘Negro Nayarit’, ‘Negro Tacaná’ and ‘Negro Citlali’, all of indeterminate growth habit type II.