Development of Short-Statured Soybean Cultivars1
- R. L. Cooper2
A soybean [Glycine max (L.) Merr.] breeding program which emphasized short stature was carried out to alleviate the effect of lodging in reducing seed yields. The primary approach taken was to cross high yielding indeterminate (Dt1) cultivates grown in the northern United States with high yielding determinate (dt1) cultivars grown in the southern U.S. with selection in the resultant progeny for high yielding determinate plant types adapted to the Midwest. From 150 crosses each year determinate, short-statured progeny were selected in the F2 and subsequent generations and evaluated for yield, using an early-generation testing procedure. Short-statured selections with adaptation to high yield environments were developed that exceeded the yield of broadly adapted “universal” cultivars when grown in their specific area of adaptation. The determinate gene (dt1) and other genes which complement dt1 from southern U.S cultivars were most useful in producing the high yielding short-statuted types. Introducing the dt1 gene from determinate isolines of indeterminate cultivars produced short-statured progeny, but high productivity was not obtained. The addition of the E1 gene in combination with dt1 was also ineffective in producing high yielding short-statured types. The short-statured lines were more responsive to narrow rows and high seeding rates than indeterminate cultivars. Narrow row spacing (17-cm) at a seeding rate of 75 seeds/m2 produced maximum yields. The short-statured lines, because of their determinate growth type, were less able to compensate for early season moisture streess than standard-height cultivars. Thus the short-statured types selected produced very high yields in good environments, but with some loss in yield in poor environments.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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