|WIEBBECKE, CHRISTIANA - Iowa State University|
|CIANZIO, SILVIA - Iowa State University|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/2/2012
Publication Date: 7/1/2012
Citation: Wiebbecke, C.E., Graham, M.A., Cianzio, S.R., Palmer, R.G. 2012. Day temperature influences the male-sterile locus in soybean. Crop Science. 52(4):1503-1510.
Interpretive Summary: The coordination of male and female development is necessary for seed production in plants. Any interruptions in development may lead to partial or complete sterility. A genetic abnormality in male development resulted in a male-sterile, female-fertile soybean plant. This plant was designated ms9. These ms9 plants may produce seed when grown at certain temperatures in controlled environments. Our goal was to determine the environment where no seed was produced and where abundant seed was produced. As day temperature increased from 30 C to 35 C seed on ms9 male-sterile, female-fertile decreased to about one seed per plant. Night temperature did not affect seed number. These results suggest that controlled environments where day temperature is 35 C during flowering would be favorable for hybrid seed production. Hybrid seed produces hybrid plants which will express heterosis; or greater seed production. The environmentally sensitive mutant would have application in plant breeding programs to produce more seed in an efficient manner. This would result in more rapid progress in variety development and early release of varieties to farmers.
Technical Abstract: Cultivated soybean [Glycine max (L.) Merrill] is a major source of oil and protein in global food production. As demand for soy-based products increases, it is essential for breeders to find ways to increase yield beyond conventional methods. Alternative methods of cultivar development need to be identified. Our objectives were to determine if the ms9 locus conferring male-sterility in soybean was environmentally sensitive, and if it were, to determine which environments could be used in hybrid seed production. This was accomplished through characterization of variation in pollen phenotype and selfed seed-set among progeny of soybean genotype T359H (Genetic Type Collection number T359H), a heterozygous maintainer line for the ms9 locus. T359H was evaluated in seven environmental regimens in growth chamber experiments. We used a split-plot design to test the effect of temperature regimens and male-sterile phenotypic classifications within chambers. As day temperature increased from 30 C to 35 C, selfed seed-set on male-sterile, female-fertile plants decreased. Conversely, night temperature affected neither fertile male-sterile or female-fertile selfed seed-set. This suggests that controlled environments where day temperature is 35 C during the flowering period could be favorable for hybrid seed production utilizing ms9 as the source of male-sterility. These temperature conditions and their effect on ms9 may provide an alternative method to produce hybrid seed in soybean cultivar development programs.