Improving Emergence of Modified Phosphorus Composition Soybeans: Genotypes, Germplasm, Environments, and Selection

Abstract

Commercial production of soybeans [Glycine max (L.) Merr.] with reduced phytate and increased inorganic phosphorus has nutritional benefits but is challenged by poor seedling emergence. An agronomic trial evaluated emergence of advanced lines derived from the CX1834 and V99‐5089 low phytate germplasm at six locations in 2009 and 2010. In 2010, seed produced in 12 environments was evaluated in an extended cold germination test (ECGT) and in a replicated field emergence test in Warsaw, VA. Objectives were to evaluate ECGT as a selection tool for improving germination and emergence of low phytate soybeans and to determine the effect of the seed production environment on emergence in different low phytate soybean germplasm. Genotypic, environmental, and the genotype × environment interaction effects were significant (p < 0.001) for emergence in the agronomic trial, ECGT, and field emergence test. Three lines were not significantly different from the two control cultivars for emergence in 12 environments. Yields of the best emerging lines were not significantly different from the control cultivars. The ECGT and field emergence test were significantly correlated (r = 0.78) but the ECGT severely reduced germination as compared with the field emergence test. Poor germination in the ECGT did not always translate to poor emergence under field conditions, preventing the use of ECGT as a selection tool or in determining seeding rates for the Southeast and Mid‐Atlantic regions.