YIELD AND AGRONOMIC CHARACTERISTICS OF SOYBEAN IN THREE SOWING DATES IN THE YAQUI VALLEY, SONORA

Abstract

Soybean (Glycine max (L.) Merr.) is the second most important crop al the Yaqui Valley, Son ., where most farmers cultivate it in a crop rotation system with wheat (Triticum aestivum L.). However, this cultural practice causes a significant delay in the soybean planting time due to the sbort period available for land tillage after wheat harvest. Therefore, the agronomic performance of five soybean varieties (Suaqui'86, Batuc'86, Tamazula S'80, Harbar'88 and Cajeme) was evaluated on three planting dates (May 9, May 24 and June 6). Results showed that: 1) A delay in the planting date reduced seed yield and plant height, and delayed the onset of
seed filling and the seed physiological maturity; 2) May 9th was the optimal planting date; 3) The intermediate type varieties had a better agronomic performance in the three planting dates, and 4) Grain yield and seed size showed a high correlation (r = 0.63^**).