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ARS Home » Midwest Area » Ames, Iowa » Corn Insects and Crop Genetics Research » Research » Publications at this Location » Publication #77924
Title: ASSIGNMENT OF THE FR3 LOCUS TO SOYBEAN LINKAGE GROUP 9

Author
item Palmer, Reid
item CHEN, X - ISU

Submitted to: Journal of Heredity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/8/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Genetic characteristics that tend to go together from parents to offspring are said to be linked. Linked traits that include only desirable characteristics are favored by plant breeders. Linked traits can also be used in genetic studies. Many times selection of traits that can be easily classified, and accurately classified can be determined first. Then after a few generations of breeding the other trait should be monitored to be certain that it is carried along during the breeding process. This is especially efficient if the difficult to monitor trait requires expensive equipment or chemicals (e.g., proteins) or is a plant pathogen (e.g., nematodes) where sophisticated inoculations or culture conditions are necessary. Root fluorescence was used to follow a protein (enzyme, acid phosphase) in a genetic linkage study. A new gene (trait) was added to soybean linkage group 9, and we determined the order of the new trait to three existing traits. Finally, it was shown that the linkage intensity (distance between two traits) depended upon the parents used to produce the progeny. This observation will be helpful when selecting parents to transfer desirable linkages or to break undesirable linkages, and will benefit scientists who are working with soybeans.

Technical Abstract: A study was conducted to determine linkage relationship between the loci Fr3 (root fluorescence) and Ap (acid phosphatase) in the soybean [Glycine max (L.) Merr.], as well as to ascertain the linkage relationship of Fr3 with two other loci in the soybean classical Linkage Group 9. Exact plant-to-plant reciprocal crosses were made between near-isogenic line Hark-Fr3 and near-isogenic line Clark-ti (Kunitz trypsin inhibitor null) and Hark-Fr3 with cultivar 'Norredo'. F2 segregation data, for the Fr3-Ap gene pair from reciprocal crosses of Hark-Fr3 x Clark-ti, gave a recombination value of 4.51 +/- 0.55 with 1464 F2 plants, however, reciprocal crosses of Hark-Fr3 x Norredo gave a recombination value of 10.25 +/- 0.83 with 1344 F2 plants. Small cryptic structural differences in Linkage Group 9 chromosomes of Hark-Fr3, Clark-ti, and Norredo were hypothesized to influence recombination frequency. Finally, the gene order rof Fr3-Ap-Ti-Lap1 (leucine aminopeptidase) was established for classical Linkage Group 9 in soybean.