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item Devine, Thomas

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/7/2005
Publication Date: 7/1/2005
Citation: Devine, T.E. 2005. Registration of TW 98-1 Soybean Genetic Stock. Crop Science. 45:1674-1675.

Interpretive Summary: The genes that control the inheritance of living things are located on string-like structures, called chromosomes, in the cells of living things. During reproduction the genes on the chromosomes can become re-assorted into new combinations by a process called crossing-over. This process of re-assortment gives rise to new and unique combinations of genes in the unique new individuals formed by this process. In plant breeding and selection, the new combinations of genes formed by crossing-over are the basis for developing new varieties of plants that are useful in agriculture. In addition to crossing-over during reproduction, crossing-over is thought to occur during regular cell division, but this type of event is thought to be very rare, since evidence of the event is rarely seen. Twinspots are thought to be evidence of these events. The soybean line TW 98-1 shows a high frequency of these twinspots, and therefore, was released by USDA to provide scientist investigating this type of crossing-over with a tool to use in their research. This registration article describes the twinspots occurring in TW 98-1 and tells scientist how to obtain seed for their studies.

Technical Abstract: The soybean line TW 98-1 displays an exceptionally high frequency of twinspots on the foliage during the juvenile growth stage. The twinspot phenomenon has been observed in several species, but is sufficiently rare to have merited investigation by a number of researchers. The twinspot phenomenon has been attributed to somatic crossing-over. TW 98-1 was released by the USDA to provide an experimental tool for plant geneticists studying the phenomenon of twinspots and somatic crossing over. TW 98-1 is an F8 derived line from the cross of BV-4 X PA10-1-1. BV-4 was derived from the cross of T135 X PI 83945-4. PA10-1-1 was derived from the cross of PA4-11-b X BSR 201. PA 4-11b was developed from the 4-way cross (Wilson 6 X Forrest) x (Perry X L76-0253). L76-0253 is an F6 segregate of the cross Williams x PI229358. TW 98-1 carries the y9 allele, which conditions bright yellow green colored leaves rather than normal dark green colored leaves. The twinspots are apparent on the upper surfaces of the unifoliolate and early trifoliolate leaves of TW 98-1 during the juvenile growth period. The twinspots are of variable size and are apparent as immediately adjacent sectors differing in color with a dark green sector bordering a white sector. The sectors are discernable against the background of the light green leaf color. In a greenhouse test, TW 98-1 has shown twinspot frequencies averaging 1.18 for the unifoliolate leaves, 4.7 for the first trifoliolate leaves, 1.27 for the second trifoliolate leaves and 0.30 for the third trifoliolate leaves.