IMPORTANCE OF THE PRE-FLOWERING GROWTH STAGE FOR COMMON BEAN YIELD

Abstract

The objective of the present study was to determine the importance of the pre-flowering growth stage for common bean yield. In two assays, the common bean BRS-Pérola, BRS-Valente and Jalo Precoce cultivars were sown at five different dates, from April to August, in 2001 and 2002, at Embrapa Arroz e Feijão, in Santo Antônio de Goiás, Goiás State, Brazil. The experiments were carried out under conventional tillage, in a randomized split-plot block design, with four repetitions. Physiological parameters related to common bean plant growth, development and yield were correlated with temperatures and solar radiation incidence, during the pre-flowering plant growth period. Increases of minimum temperature, solar radiation, and N absorption rate, and decrease in N efficiency use, up to the third trifoliolate leaf stage, were correlated with yield reduction. The phenological period between emergence and third trifoliolate leaf is the most important one for common bean yield determination, when compared with the total pre-flowering period.

KEY-WORDS: Phaseolus vulgaris; common bean development; temperature; solar radiation.