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Wheat Information Service
Number 85: 31-34 (1997)
Research article

Agronomic performance of plant height near-isolines of Nugaines wheat

R E. Allan

Wheat Genetics, Quality, Physiology and Disease Research Unit, USDA-ARS, PO Box 646420, WSU, Pullman, WA 99164-6420


Summary

Semidwarf wheat production escalated in the U. S. Pacific Northwest after the development of Gaines and Nugaines. Nugaines replaced Gaines and became widely grown because of its high yield capacity and heavy test weight. This study examines the contribution of semidwarf genes (Rht1 and Rht2) and background genes to the agronomic performance of Nugaines. Near isogenic lines (NILs) representing each of the four possible genotypes of the Rht1 and Rht2 loci were selected from a backcross-derived population of Chugoku, 81/5*Nugaines; Nugaines has Rht2 while Chugoku 81 has Rht1. The agronomic performance of the four sets of NILs revealed that the Nugaines genetic background is uniquely compatible with the Rht1 and Rht2 genes. The three semidwarf genotypes had mean yields of 22 to 36% greater than the nonsemidwarf genotype. In other genetic backgrounds, yield increases associated with semidwarf genotypes averaged 2 to 16% greater than nonsemidwarf NILs. Contrary to results with other genetic backgrounds, the Rht2 gene did not significantly lower test weight in the Nugaines genetic background. Test weight received special emphasis in the breeding program of O.A. Vogel because it affects market price and milling quality.


Introduction

Semidwarf wheat production began in North America in 1961 with the release of Gaines (Vogel 1964). Gaines is a Norin 10 derived semidwarf. The transition to semidwarf wheat production, especially in the U.S. Pacific Northwest was rapid and had major economic impact for the region (Patterson and Allan 1981; Dalrymple 1980). While Gaines was the first semidwarf variety to be grown, its sister line, Nugaines , released in 1965 had even greater impact because it had improved quality, stripe rust resistance, and higher test weight (Vogel and Peterson 1974). Nugaines was the most widely grown soft white winter wheat variety in the U.S. Pacific Northwest (PNW) for over 10 years. It is estimated that semidwarf wheat increased PNW wheat production by 30%. This study attempts to determine the contribution of Norin 10-derived semidwarf gene(s) to yield and other agronomic characteristics of Nugaines.

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