Effect of temperature on a soybean [Glycine max (L.) Merr.] mutant

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Soybean is influenced by temperature and light, and global warming has been shown to reduce soybean yields. In this study we tested the germination of TM-Miniature, a soybean mutant with dwarf phenotype, and TM-Normal and two other genotypes in response to high temperatures of 38 °C, 40 °C, and a control temperature of 28 °C. The results showed that a mutation might cause TM-Miniature seedlings to be more thermotolerant than TM-Normal and the two other genotypes at emergence. We also examined the morphology and anatomy of TM-Miniature and TM-Normal in response to a range of temperature and photoperiods conditions. The data indicated clearly that TM-Miniature phenotype was influenced by night temperature and light interruption of the dark period. Leaves of TM-Miniature plants were very small at low night temperature while the leaf thickness remained unchanged. The upper and lower epidermal cell layers decreased in thickness as nighttime temperature increased. In addition, stomatal density and stomatal index decreased in TM-Miniature. TM-Miniature is controlled by a single mutant gene. Glyma14g36890 is an interesting candidate gene and was found near the Satt560 marker that co-segregated with the miniature trait. This gene was amplified and sequenced to study nucleotide differences between TM-Normal and William 82. The sequenced armadillo gene in our study did not show nucleotide differences in the predicted promoter region and exon gene region. However, there appear to be sequence differences in a predicted intron.