Variation among Soybean Breeding Lines in Relation to Yield and Seed‐Fill Duration

Abstract

AbstractThere are exceptions to the positive relationship between seedfilling period (SFP) and seed yield in soybean [Glycine max (L.) Merr.]. Studying genotypes that do not show a positive relationship between SFP and yield may aid in identifying factors that influence seed yield or SFP, or both. The objective of this research was to analyze groups of soybean genotypes that differed in their SFP‐yield relationship, and determine which factors affected seed yield. Eight experimental lines were selected from a ‘Williams’ ✕ ‘Kanrich’ cross to represent the four SFP‐yield combinations of long or short SFP and high or low yield. Replicated field plots were grown in 1984 and 1985 at Urbana, IL, on a Flanagan silt loam (fine, montmorillonitic, mesic Aquic Argiudoll). Data taken in each year included: SFP, seed yield, harvest indices for dry matter and N, total flowers, total pods at three stages (5 mm long, pod containing a seed 3 mm long, and mature pod), and total N and dry matter at the beginning and end of SFP. Early flowering was related to SFP, but not to yield. Rate as well as duration of seed fill can influence seed yield. Total N in the plant at the end of SFP was related to yield, but not to SFP. Total N and dry matter assimilated during SFP, harvest indices for N and dry matter, and final seed yield were all related.