Soybean Genetics Newsletter: Volume 14, Issue 1
There have been numerous papers dealing with amylase isozymes in soybeans (i.e., Morita and Yagi, 1979; Hildebrand and Hymowitz, 1980; Kiang, 1981; Adams et al., 1981; Mikami et al., 1982). All have reported beta-amylase as the predominant amylase type in most soybean lines and that varietal differences in beta-amylase either for electrophoretic mobility, pl, or enzyme activity were observed. Gorman and Kiang (1978), Hildebrand and Hymowitz (1980), Kiang (1981), and Griffin and Palmer (1986) reported similar results concerning the inheritance of different beta-amylase electrophoretic variants (i.e., variants were the result of five different alleles at the Spl locus).
Normal soybean seeds contain at least three lipoxygenase isozymes, called L-1, L-2, and L-3. These isozymes are responsible for the generation of objectionable grassy beany and green flavors which build a barrier against the wide utilization of soy protein products. Recently, the three types of mutants lacking L-1 (Hildebrand and Hymowitz, 1981), L-2 (Kitamura, 1984), and L-3 (Kitamura et al., 1983), respectively, were found.
There has been much recent interest in the development of crops that are tolerant or resistant to the herbicide glyphosate. Glyphosate is a nonselective systemic herbicide that can control many annual and perennial weeds regardless of their size, a characteristic atypical of most selective herbicides used in crop production. Crop tolerance to glyphosate would be beneficial as it would provide growers, for the first time, the opportunity to control almost all weeds with a single herbicide application.
A series of seven differential strain groups of SMV, labelled Gl to G7, were reported by Cho and Goodman (1979). Buzzell and Tu (1984) added another strain, G7A, and Lim (1985) added an additional strain, Cl4. We have been studying the genetic relationships among the cultivars that define the strain groups. Our intial studies involved the cultivars 'Marshall', 'Kwanggyo', 'York', 'Ogden', and PI 96.983, which differentiate the seven strain groups of Cho and Goodman.