Seed Growth Characteristics of Soybean Genotypes Differing in Duration of Seed Fill¹

Abstract

Seed growth and development is an important part of the yield production process in grain crops. Experiments were conducted in the field for 2 yr to determine the seed growth characteristics of soybean [ Glycine max (L.) Merr.] genotypes that varied widely the duration of seed fill. Fifty‐nine genotypes were grown in 1982 on a Donerail silt loam soil (fine, mixed, mesic Typic Argiudolls) and measurements of seed growth rate (SGR), final seed size (FSS), and effective filling period (EFP) were made. The 59 genotypes exhibited a wide range in SGR, FSS, and EFP. Although SGR and FSS were significantly correlated ( r = 0.76**, significant at the 0.01 probability level), subsets of genotypes could be identified that exhibited a wide range in FSS with no variation in SGR. In 1983, seven genotypes (six plant introductions and one cultivar) were selected, on the basis of the 1982 data, to have a relatively similar SGR but a wide range in FSS and EFP. These genotypes were grown on a Maury silt loam soil (fine, mixed, mesic Typic Palendalfs). Fruit samples were taken at weekly intervals to characterize seed development. Cotyledon cell numbers were measured on selected cultivars in 1982 and 1983. For genotypes that differed in EFP, the patterns of dry matter accumulation and seed moisture changes with time were similar to those previously reported. The number of cotyledon cells per unit mass of seed decreased as FSS increased indicating that differences in cell size were associated with the differences in seed size in these genotypes. These data indicate that variation in FSS among genotypes can be associated with either variation in SGR and/or filling period duration.