Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 20, 1996
Publication Date: N/A
Interpretive Summary: Recently soybean growers in the Mid-South USA have shifted to early maturing varieties and earlier planting dates. This generally has improved yields and results in August and September crop maturities. Maturity during that period can cause reduced germination of seed harvested. This could hamper seed production of early varieties in the region. The impermeable seedcoat (ISC) trait can protect seed quality of late maturing varieties exposed to weathering after maturity. The objective of this study was to develop early maturing ISC lines and determine the effect of that trait on seed germination. D86-4565 a breeding line that carries the ISC was crossed with two early maturing varieties. Normal seedcoat and ISC lines were derived from each cross. Those lines were grown during 1993 and 1994. Seed harvested was evaluated in standard germination tests. Mean germination of ISC and normal seedcoat lines were compared within each cross for each year. Results indicate that ISC lines had higher germination in only one cross in one year. In the other three comparisons there was no significant difference between ISC and normal seedcoat lines. Germination was highly correlated with maturity date in 1993 but not in 1994. It was concluded that the ISC trait would not be consistently effective in improving seed quality of early maturing soybean varieties.
Technical Abstract: Recently some soybean [Glycine max (L.) Merr.] growers in the southern USA have shifted to early maturing cultivars to avoid drought which often occurs during late summer. The quality of seed of cultivars that mature early (August and early September) is often poor. The impermeable seed coat (ISC) trait has provided protection for seed exposed to late season weathering;however, it is not known if it will improve seed quality of early maturing soybean. The objective of this study was to determine the effect of ISC on germination of seed harvested from early maturing lines. ISC and permeable seed coat (PSC) lines derived from the crosses D86-4565 X C1747 and D86-4565 X C1813 were used in the study. These lines ranged in maturity from late August to early October. Selected lines were grown at Stoneville, MS in 1993 and 1994. Standard germination tests were used to assess effect. ISC lines were significantly higher in germination in one cross (D86-4565 X C1747) in 1993 but did not differ from PSC lines in either cross in 1994. There was a strong positive correlation between mean germination and maturity date in 1993 for each of the four genotypic classes. Maturity in 1994 was not correlated with germination in three of the four genotypic classes. Results indicated that ISC was not consistently effective in protecting seed quality in early maturing lines. Several early maturing lines with PSC showed acceptable germinations in both years indicating potential for improvement of this trait.