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Gene discovery could lead to better soybean varieties

Researchers from Purdue University and the University of Nebraska-Lincoln have discovered a soybean gene whose mutation affects plant stem growth, a finding that could lead to the development of improved soybean cultivars for the northern United States.

Purdue Agronomy Professor Jianxin Ma (pronounced Jen-SHIN' Ma) and collaborators identified a gene known as Dt2, which causes semi-determinacy in soybean plants. Semi-determinate soybean plants – mid-size plants that continue vegetative growth even after flowering – can produce as many or more pods than current northern cultivars but do not grow as tall. Their reduced height makes them more resistant to lodging, a bending or breaking of the main plant stem.

“This gene could help us improve the yield potential and adaptability of soybeans for specific growing areas,” Ma said. “We can now focus on developing a variety of elite semi-determinate soybean cultivars, which could perform very well in high-yielding, irrigated environments such as Nebraska and Northeastern Indiana.”

Soybean cultivars are of-ten divided into two groups: indeterminate – tall plants whose main stem continues to grow after flowering, and determinate – shorter, bushier plants whose main stem halts growth when blossoms begin to form.

For northern soybean pro-ducers, semi-determinate soybean plants could represent a “Goldilocks” cultivar, a “just right” alternative between the two.

Only one semi-determinate soybean cultivar, NE3001, is common in the United States. Having pinpointed Dt2 will enable Ma and his researchers to use natural plant breeding methods to develop a variety of semi-determinate cultivars.

Ma said this type of mutation appears to be unique to soybeans as semideterminancy in other plants such as tomatoes and chick-peas is caused by a different genetic mechanism.