Rendimiento de variedades de soya evaluadas en diferente fecha de siembra en campeche, méxico

Campeche is one of the major soybean (Glycine max L. Merr) producing states in Mexico, with an average yield of 2.6 t ha-1; however, in it there is a significant variation on yield across years. Some authors have associated these variations to factors linked to genotypes, sowing dates and their interactions. Taking in account that there is reduced information on this topic, the objective of this study was to evaluate the effect of four sowing dates (June 19, July 10, August 2 and August 20) across 2017 and 2018 on the yield of nine soybean cultivars (H100, H200, H300, H400, H600, Tamesi, Vernal, Luziania and Mariana). The experiment was established in a split plot experiment arranged in a randomized complete block design. The statistical analyses were variance analysis, mean test, principal component analysis and SREG for the EG interaction analysis. Results showed that the highest yield (3 t ha-1) were observed on June 19 and July 10, and was associated with the traits grain weight, number of branches per plant and number of seeds per plant. In later sowing dates, it was observed a decrease in plant yield in the range of 5.7-10.0 g day-1, that was associated to a decrease in grains weight, number of branches and seeds and pods per plant. H100 cultivar excelled in yield in June 19 sowing date and H200 in July 10. The cultivars with the lowest yields were Mariana (2.3 t ha-1) and Luziania (2.4 t ha-1). Our results suggest that late sowing dates in august are not recommended for soybeans grown in Campeche.