Inheritance of test weight and kernel weight in eight durum wheat crosses

Clarke, F. R., Clarke, J. M., Pozniak, C. J. and Knox, R. E. 2009. Inheritance of test weight and kernel weight in eight durum wheat crosses. Can. J. Plant Sci. 89: 1047-1057. High test weight and uniform kernel size are important grading factors for durum wheat [Triticum turgidum L. ssp. durum (Desf.) Husn.] because both are associated with semolina yield. The objective of this research was to determine the inheritance and heritability of test and kernel weights to facilitate development of selection strategies. Eight durum populations were grown in replicated, multi-location, multi-year field trials. Test weight and kernel weights were determined on all plots after harvest. Both traits were affected by genotype and to a lesser extent by year or location. Genotype environmental interactions were generally minor. Trial means for test weight ranged from 72.7 to 81.0 kg hL(-1) and from 31.5 to 50.9 mg for kernel weight. All populations showed bi-directional transgressive segregation for both traits, and the estimated number of effective factors controlling them ranged from 4 to 23, indicating quantitative inheritance. With the exception of one Population, heritability of test weight ranged from 0.80 to 0.92 and of kernel weight from 0.83 to 0.93. Both traits generally showed positive phenotypic and genotypic correlations with plant height. Also, mean test weight and kernel weight were higher for the gibberellic acid-sensitive (tall) than for the insensitive (semidwarf) group within populations segregating for gibberellic acid response.