QTLs for black-point resistance in wheat and the identification of potential markers for use in breeding programmes

Abstract

Quantitative trait loci (QTLs) for black-point resistance have been mapped in two doubled haploid-derived wheat populations, each thought to contain unrelated sources of resistance. In the 'Sunco' x 'Tasman'-derived population, QTLs were located on chromosomes 1D, 2B, 3D, 4A, 5A and 7A with each QTL explaining between 4 and 15% of the observed phenotypic variance. QTLs were contributed by both parents. In the 'Cascades' x 'AUS1408'-derived population, QTLs from 'Cascades' were identified on chromosomes 2A, 2D and 7A with each QTL explaining between 12 and 18% of the phenotypic variance. Several markers were identified which are promising candidates for use in marker-assisted selection programmes. If one, two or three of these markers would have been used to select for black-point resistance in the 'Sunco' x 'Tasman' population, then with one marker 34 of 39 resistant lines, with two markers 23 of 32 and with three markers 17 of 32 would have been selected. At the same time, 67 false positives obtained by selecting with one marker are reduced to 24 by selection with two markers and to 11 by selection with three markers. Similarly, if one, two or three markers are used to select for black-point resistance in the 'Cascades' x 'AUS1408' populations, then with one marker 25 of 31 resistant lines, with two markers 26 of 31 and with three markers 10 of 31 are selected. At the same time, 14 false positives are obtained with one marker are reduced to six by selection with two markers and no false positives are selected using three markers.