Variation and Covariation of Agronomic Traits in Durum Wheat1

Abstract

Experience has shown that large kernels and high test weight have been associated in inheritance with tallness and lateness in the breeding of durum wheat, Triticum durum Desf. To determine if these unfavorable associations were genetic, F2, F3, and F4 generations of four crosses were studied in the field. Phenotypic and genotypic correlation coefficients did show that selection for short, early‐maturing plants might result in lines with lower kernel weight and test weight in some segregating populations. However, the selection of short, early, large seeded lines appeared to be possible. Significant positive correlations occurred for kernel weight with grain yield and test weight and grain yield with test weight.Average heritabilities for kernel weight, test weight, and number of kernels per spike were 72, 67, and 69% respectively. Expected and actual gains due to selection agreed well for maturity, height, kernel weight, test weight, and number of kernels per spike.The data showed that kernel weight might be used effectively for rapid indirect selection of high test weight and, possibly, higher yield in large F2 and F3 populations.