Jm. Costa et We. Kronstad, ASSOCIATION OF GRAIN PROTEIN-CONCENTRATION AND SELECTED TRAITS IN HARD RED WINTER-WHEAT POPULATIONS IN THE PACIFIC-NORTHWEST, Crop science, 34(5), 1994, pp. 1234-1239
Grain yield and grain protein concentration are often negatively assoc
iated in wheat (Triticum aestivum L.). When grain yield increases and
grain protein concentration decreases, the milling and baking quality
of bread flour can be affected. In the Pacific Northwest region of the
USA, grain yield of wheat is usually high and grain protein concentra
tion is low. Parents, F-4 and F-5 generations of two crosses were soli
d-planted in two environmentally diverse but high-yielding sites in Or
egon to study the association of grain protein concentration with grai
n yield and biological yield, harvest index and related traits in the
Pacific Northwest's environment, and to suggest a selection criterion
to increase grain yield while maintaining or increasing grain protein
concentration. Correlation coefficients showed moderate negative assoc
iations between grain protein concentration and grain yield, and also
between grain protein concentration and harvest index. Genetic correla
tions were larger than phenotypic correlations, while environmental co
rrelations were low, suggesting the presence of negative genetic relat
ionships between grain protein concentration with grain yield and with
harvest index. Grain yield and harvest index were the most important
traits affecting grain protein concentration as estimated by path coef
ficients analyses. We suggest that selection for high grain yield, whi
le maintaining or increasing grain protein concentration, should not b
e based on further increases of harvest index, but rather on increasin
g biological yield.