An evaluation of nine backcross-derived wheats
AuthorCoit A. Suneson
Author AffiliationsCoit A. Suneson was Agronomist and Regional Coördinator, United States Department of Agriculture, and Associate in Agronomy, University of California.
Hilgardia 17(15):501-510. DOI:10.3733/hilg.v17n15p501. September 1947.
Abstract does not appear. First page follows.
The improvement of established varieties of wheat through use of the backcross method of breeding was pioneered at the California Agricultural Experiment Station (Briggs, 1930).3 It seems advisable to present a new appraisal of the method that is based upon recent progress. For the plant breeder, the farmer, and the miller, the principal concern involves the degree of similarity, or difference, between a known commercial variety and its improved successor evolved by backcrossing where injury from diseases and insects does not occur. The results of numerous comparisons under such conditions are presented here. The procedures followed in the breeding of nine improved varieties and the genetic nature of these varieties are also discussed.
Review of Literature
Theoretical assumptions regarding homozygosity of backcrossed populations and their similarity to their prototype varieties have been presented by (Briggs (1930), (1938). These assumptions furnished the justification for the release of the improved varieties for commercial culture before extensive comparative performance data were available. Subsequently, a series of reports, each treating a successively larger body of data have been presented (Briggs, 1938); (Suneson and Briggs, 1941); (Suneson, Riddle, and Briggs, 1941); (Riddle and Baker, 1944) emphasizing the similarity between the improved varieties and their prototypes. The improved varieties have been widely accepted by California farmers because of the economic advantage of the obvious improvements. In 1939, Baart and White Federation occupied 56 per cent of the California wheat acreage (Clark, 1942). In 1944, however, Baart 38 and White Federation 38, together with a very small residue of their prototypes, occupied approximately 70 per cent of the California wheat acreage, according to all available reports. This trend had been predicted (Suneson, 1945), but it was accelerated by state-wide rust damage in 1940 and 1941.
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