Early and Traditionally Maturing Soybean Varieties Grown in Two Planting Systems

Abstract

Production of early maturing rather than traditionally maturing soybean [Glycine max (L.) Merr.] varieties can benefit producers through crop diversification that spreads economic risk and through earlier harvest that allows timely fall planting of winter cereals. However, planting system can influence the success of early maturing soybean production. This study was conducted to determine the effect of ANH (April, narrow 7-in. rows, high population-336 000 seeds/acre) and JWL (June, wide 30-in. rows, low population-139 000 seeds/acre) planting systems on yield, plant and lowest pod heights, and visual grain quality of early maturing (Maturity Groups [MGs] 00, 0, and I) and traditionallyl maturing (MGs III, IV, and V) soybean varieties. In 1987, early maturing soybean varieties yielded more than 30 bu/acre when planted in the ANH system, but yields of these varieties were approximately 50% lower in the JWL system. 'Hodgson 78' (MG I) yielded 41 bu/acre in the ANH system in 1987; this yield was higher than yields of all other varieties except 'Bay' (MG V) planted in the JWL system. From 1988 through 1990 in either system, Hodgson 78 yielded 20 to 30 bu/acre, which was equal to or greater than the yields of all other varieties except 'Zane' planted in the ANH system in 1990. Plant heights of early maturing varieties were generally shorter than those of the determinate varieties, 'Crawford' (MG IV) and Bay (MG V). Lowest pod height of early maturing soybean varieties ranged from 1 to 4 in. during all years, whereas later maturing varieties podded as high as 8 in. from ground level. Quality of grain varied by year, but in 1987, grain quality of the early maturing varieties was improved by the ANH planting system. These results show that early maturing soybean varieties from MG I offer a viable alternative to traditional MGs; however, additional research is needed to refine these new management systems.