ARS | Publication request: Effects of maturity and phomopsis on germination and vigor of soybean seed of near isogenic lines

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 12, 2012
Publication Date: October 10, 2012
Citation: Gillen, A.M., Smith, J.R., Mengistu, A., Bellaloui, N. 2012. Effects of maturity and phomopsis on germination and vigor of soybean seed of near isogenic lines. Crop Science. 52(6):2757-2766.

Interpretive Summary: Soybean seed quality has declined in the mid-southern USA due to the shift to soybeans that mature during Mid-August through September as opposed to October to November, which was common in the past. This decline was shown to be related to increased temperatures during seed maturation, increased levels of Phomopsis seed decay and potentially by maturity. In this study, the effects of maturity, temperature and Phomopsis longicolla, the cause of Phomopsis seed decay, on seed quality were evaluated in a field trial of two sets of near isogenic soybean lines. Isolines are soybean lines derived from a common ancestor, therefore they have the same genetic background, but each line differs from the other in one known gene, in this case genes for maturity. No effects of maturity on germination, seed vigor or hard-seededness were detected. P. longicolla level had a significant negative effect on germination in both isoline sets. P. longicolla also had a significant negative effect on seed vigor for one isoline set. P. longicolla level, not maturity, was the most significant factor in seed germination and vigor in this study. Therefore, it should be possible to produce earlier and later maturing lines with good seed germination and vigor. This study indicates that there continues to be a great need to develop of soybeans with resistance to P. longicolla and with high germinability when seed are produced in conditions of high humidity and high-temperatures.

Technical Abstract: Soybean [Glycine max (L.) Merr.] seed quality has declined in the mid-southern USA due to the shift to soybeans that mature during Mid-August through September as opposed to October to November, which was common in the past. This decline was shown to be related to increased temperatures during seed maturation, increased levels of Phomopsis seed decay (PSD) and potentially by maturity per se. In this study, the effects of maturity, temperature and Phomopsis longicolla, the cause of PSD, on seed quality were evaluated in a field trial of two sets of near isogenic soybean lines (‘Clark’ and ‘Harosoy’), where the maturity of each line within a set varied. No effects of maturity on germination, accelerated aging germination (AA) or hard-seededness were detected. P. longicolla level had a significant negative effect on germination in both isoline sets. Year had a significant effect on germination in both isoline sets. In addition, year and P. longicolla level had a significant negative effect on AA for the Clark set, and only year had an effect on AA in the Harosoy set. P. longicolla level, not maturity, was the most significant factor in seed germination and vigor. Therefore, there continues to be great need to develop of soybeans with resistance to P. longicolla and with high germinability when seed are produced in conditions of high humidity and high-temperatures.