Nitrogen Metabolism of Soybean Genotypes Selected for Seed Composition, Fasciated Stem, or Harvest Index
- Robert C. Leffel ,
- Perry B. Cregan and
- Amanda P. Bolgiano
Development of methodologies for genetically increasing the efficiency of N metabolism in soybean [Glycine max (L.) Merr.] requires the identification of desirable genetic variation. Two field experiments were conducted at Beltsville, MD, to determine the genetic variability for measures of N metabolism among soybean genotypes selected for diversity in chemical composition of seed, podding habit, and harvest index. Nitrogen accumulation and partitioning, and N2 fixation were determined, the latter by the difference method utilizing the nonnodulating ‘Clark’ rjl genotype. Genotypes were evaluated at R5 (beginning seed) and R8 (full maturity) reproductive stages, to provide comparisons among genotypes for agronomic and N characteristics, including plant maturity; seed yield and protein; seed filling interval (R5 to R8); total harvest and total N harvest indices; pod N partitioning; and N2 fixation, N remobilization efficiency, and remobilized N. Results indicated that in most comparisons, high-protein soybean exhibited a shorter seed-filling interval, R5 to R8, as compared to low-protein soybean. Measures of N metabolism that can contribute to enhanced N metabolism and seed yield and protein were generally lacking among diverse germplasm. Current cultivars were equal or superior to plant introductions or fasciated lines for measures of N metabolism.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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