Growth, yield components and seed composition of two soybean cultivars as affected by manganese supply

Abstract

The influence of manganese nutrition on growth and yield of two soybean cultivars (Lee and Bragg) was studied in sand culture. Increasing the manganese concentration from 1.0¦M to 275¦M reduced vegetative growth and grain yield in both cultivars, the reduction being greater for Bragg than for Lee. The reduction in grain yield at high manganese levels resulted mainly from a reduced individual seed weight and a lower number of pods, with a slight reduction in the number of fertile nodes. There was no effect of high manganese supply on oil and protein levels or on the germination percentage of harvested seed. Manganese deficiency reduced vegetative growth, advanced flower initiation and pod formation, and decreased the grain yields of both cultivars. The reduced seed yield was mainly due to a reduction in the number of pods per plant and the individual seed weight. Manganese deficiency also reduced the concentration of oil in the seeds, but there was no effect on seed protein level or on the germination percentage cf harvested seed. Seed manganese concentration increased with the supply of the nutrient, but no difference in concentration was found between the two cultivars.