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Agronomic responses to a factorial combination of soybean canopy modifying genes
Abstract
Soybean (Glycine max (L.) Merr.) plant geometry and canopy architecture can be radically altered by qualitative genes. Five genes, in near-isogenic lines, were used to construct a 2$\sp5$ factorial array of all possible homozygous phenotypes in each of the two cultivars "Clark" and "Harosoy". The five gene loci regulate: growth habit $(Dt\sb1/dt\sb1)$, leaflet number $(Lf\sb1/lf\sb1)$, leaflet shape (Ln/ln), leaf color $(Y\sb9/y\sb9)$, and pubescence density $(Pd\sb1/pd\sb1)$. The 32 Clark and 32 Harosoy lines were planted in replicated yield trials at two locations in 1986. Effects of individual genes and intergenic interactions (epistasis) were determined for several agronomic traits. Individual gene effects on yield ranged from $-$333 kg ha$\sp{-1}$ for $y\sb9$ to +279 kg ha$\sp{-1}$ for $dt\sb1$. Epistasis for yield occurred in six of ten two-way intergenic interactions. In one example, yields of $Pd\sb1Dt\sb1, Pd\sb1dt\sb1, pd\sb1Dt\sb1,$ and $pd\sb1dt\sb1$, were 2,284, 2,711, 2,466, and 2,597 kg ha$\sp{-1}$ respectively. Interactions occurred between gene effects and cultivars, indicating that genetic background is an important component in evaluating a single gene, or combination of genes, for breeding purposes. Correlations between traits such as yield, maturity, lodging, and seed quality were significantly affected by the alleles controlling growth habit, leaf color, and pubescence density. The positive correlation between yield and plant height seen for $dt\sb1$ indicated that selection for yield in determinate lines would indirectly select taller plants. The most promising gene for use in soybean improvement was $dt\sb1$. The most promising combinations were $Lf\sb1ln$, and $Pd\sb1dt\sb1$.
Subject Area
Agronomy|Genetics
Recommended Citation
Weidenbenner, Clement, "Agronomic responses to a factorial combination of soybean canopy modifying genes" (1989). ETD collection for University of Nebraska-Lincoln. AAI9013636.
https://digitalcommons.unl.edu/dissertations/AAI9013636