192 • Technologies To Maintain Biological Diversity 



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Box 7-C. — Breeding and the Development of Gaines Wheat 



The first American soft, white, semi-dwarf, 

 winter wheat variety was released in 1956 and 

 was known by the varietal name "Gaines." It 

 was developed by farmers of the Inland Em- 

 pire region of the Pacific Northwest— a region 

 of rolling hills and deep soils that included 

 eastern Oregon and Washington and northern 

 Idaho. The flour of Gaines wheat can be used 

 in pastries, cookies, and other soft white wheat 

 products. 



Gaines wheat was responsible for major in- 

 creases in the yields of farmers in the Palouse 

 region in Washington. Fifty years ago, these 

 farms yielded an average of 15 to 17 bushels 

 of wheat per acre. Today, many farms harvest 

 more than 90 bushels per acre. These increases 

 have been the result of a breeding program that 

 dramatically restructured the wheat plant. 



High yields of Gaines wheat result from a 

 greater proportion of the plant's energy being 

 channeled into grain production. Moisture 

 and nutrients are more efficiently utilized. 

 Genes that reduce the amount of straw rela- 

 tive to grain produced per plant were incor- 

 porated into breeding lines. Short-stature 

 Gaines wheat has not only increased farmers' 

 yields, but it also has served as the main source 

 of genes for the wheat varieties of the Green 

 Revolution for which Dr. Norman Borlaug re- 

 ceived the 1970 Nobel Peace Prize. 



Wheat is not native to the United States, and 

 thus, the germplasm to develop Gaines had to 

 come from international sources. Many of the 

 necessary breeding stocks were already part 

 of the USDA's National Small Grains Collec- 

 tion, which contains wheats from many coun- 

 tries. Other materials came from individual 



Parental lines 



While Odessa 



-tard Fade' at ion 



Rio 



) vGaines 



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SOURCE: Dr. S. Deltz, USDA-ARS Western Regional Plant, IrWMrl 

 Station, Pullnnan, WA. 



breeders both in the United States and other 

 countries. The above chart shows the parent- 

 age of Gaines wheat and illustrates the numer- 

 ous crosses and selections that must occur for 

 the development of a crop variety. Today, 

 Gaines has been replaced by improved vari- 

 eties that were developed from it. 



SOURCE: Adapted from materials provided by Dr. Sam Dietz, 

 Regional Plant Introduction Station, USDA/ARS, Pullman, Wash- 

 ington, 1987. 



variation, 2) somatic hybridization, and 3) re- 

 combinant DNA technologies. 



SomacU 



riatic 



During the process of in vitro culture of 

 unorganized plant tissues, modifications fre- 

 quently arise that can be genetically stable and 

 heritable (5,75,90,91). A number of significant 



somaclonal variants have been isolated from 

 buds produced in unorganized in vitro cultures 

 (table 7-5). 



However, somaclonal variations may not al- 

 ways persist (74,90). In some cases, variations 

 can be passed on to succeeding generations, 

 but in others they are lost (75,90). In addition 

 to the problem of genetic stability, variant cells 



