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ARS Home » Midwest Area » Urbana, Illinois » Soybean/maize Germplasm, Pathology, and Genetics Research » Research » Publications at this Location » Publication #57871
Title: GENETIC ANALYSIS OF NONNODULATING SOYBEAN MUTANTS IN A HYPERNODULATED BACKGROUND

Author
item Harper, James
item NICKELL, CECIL - U OF ILLINOIS, URBANA

Submitted to: Soybean Genetics Newsletter
Publication Type: Other
Publication Acceptance Date: 4/3/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary: Nodulation is a process where a bacteria interacts with the plant to form a specialized structure (termed nodule) which allows the plant to obtain nitrogen from the air. This process is beneficial to crops, such as soybean, in replacing the need for fertilizer nitrogen application. A new gene was characterized and named which results in increased nodule formation on soybean. The relationship of this gene to other genes which prevent nodule formation was also evaluated. These findings are important to geneticists and physiologists who are attempting to enhance ability of soybean plants to obtain nitrogen from the atmosphere.

Technical Abstract: Crosses were made between two selected nonnodulating mutants (3-7 17b and 3-7 21-2, collectively referred to as 3-7...) and two previously characterized nonnodulating mutants to identify genetic control. The two 3-7... mutants were shown to carry both the rj5 and rj6 nonnodulating genes previously identified in the NN5 nonnodulating mutant. In addition, a recessive gene controlling hypernodulation was confirmed as present in the 3-7... lines. Evaluation of F2 and F2:3 families for nodulation classes confirmed that the rj1 nonnodulating gene and the combination of rj5 and rj6 nonnodulating genes epistatically suppress the hypernodulation gene. This hypernodulation gene, previously identified in the NOD 4 hypernodulating line and tentatively designated rjh, has now been approved by the Soybean Genetics Committee for naming as rj7. The putative genotype of the two 3-7... lines is Rj1Rj1rj5rj5rj6rj6rj7rj7 and the phenotype is nonnodulating.