Seed Source Affects Field Emergence of Low‐Phytate Soybean Lines

Seed production in subtropical environments is commonly used by soybean [ Glycine max (L.) Merr.] breeders to reduce the number of years for cultivar development. Low‐phytate (LP) soybean lines with the mips allele had substantially reduced field emergence when planted with seed from a subtropical source. The objective of this study was to determine if seed source also would impact the field emergence of low‐phytate lines with the pha1 and pha2 alleles. Seed of six BC 3 F 4 ‐derived LP lines, the LP donor parent CX1834‐1‐6 (CX1834), and the normal‐phytate (NP) recurrent parent B01769B019 (B019), was harvested from the field at Ames, IA, in 2005 (IA‐2005), at Ponce, PR, in January 2007 (PR‐Jan), and at Ponce, PR, in May 2007 (PR‐May). The three seed sources of the eight lines were evaluated at three Iowa locations in 2007. The mean field emergence of LP lines was 77.6% for the IA‐2005 source, 70.1% for the PR‐Jan source, and 25.4% for the PR‐May source while that of B019 ranged from 80.3 to 82.0% for the three sources. The seed source used to plant lines with the pha1 and pha2 alleles can have a significant influence on their field emergence, which can impact the development and evaluation of LP lines and on seed increases for commercial production.