Genetic markers and biochemical evaluation in the winter triticale identification and breeding.

Winter hexaploid triticale lines and cultivars were identified by protein (storage and enzyme) and DNA markers. The locus of B-Amy-2 and Adh-1 were characterized by two alleles, Mdh-1 by 3 alleles, B-Amy-1 and Mdh-2 by 4 alleles and the locus controlling cathodic peroxidase isozymes, a-amylase and esterase by 6, 9 and 12 alleles, respectively. Intra-and intervarietal variation, for the enzyme coding loci, gliadin and glutenine were found. According to the isoenzyme analysis and the grain quality lines 28 and 49 (softness, high amylose content: 28.9-25.6, protein: 11,6- 11,2% and albumin 50-43%) could be marked as genotypes suitable for brewing and were characterized by allele b-Amy-1-b. Genotypes 1420 and 1434 are good for bread making with a hardness index between 52 and 62 and a W value (alveograph) of 110- 120. Allele a-Amy-b is positively correlated with amylose content (r = 0.601) and negatively with protein content (r - 0.490), the correlation of the presence of allele 1-Amy-1-b and amylose content is r- 0.549. Three breeding lines had 40% amylose content in grain and flour. Furthermore, the presence of allele Mdh-1 was associated with a high content of glutenin (r = 0.568), and controlled by genes localized in a single linkage group. Also statistically significant correlations for Mdh-1 -a and Prx-D containing albumin to total protein (%) could observed. It was illustrated that the peroxidase activity and free proline content can be used as resistance markers to abiotic factors.

A high-density genetic map of hexaploid wheat (Triticum aestivum L.) from the cross Chinese Spring x SQ1 and its use to compare QTLs for grain yield across a range of environments.

A population of 96 doubled haploid lines (DHLs) was prepared from F1 plants of the hexaploid wheat cross Chinese Spring x SQ1 (a high abscisic acid-expressing breeding line) and was mapped with 567 RFLP, AFLP, SSR, morphological and biochemical markers covering all 21 chromosomes, with a total map length of 3,522 cM. Although the map lengths for each genome were very similar, the D genome had only half the markers of the other two genomes. The map was used to identify quantitative trait loci (QTLs) for yield and yield components from a combination of 24 site x treatment x year combinations, including nutrient stress, drought stress and salt stress treatments. Although yield QTLs were widely distributed around the genome, 17 clusters of yield QTLs from five or more trials were identified: two on group 1 chromosomes, one each on group 2 and group 3, five on group 4, four on group 5, one on group 6 and three on group 7. The strongest yield QTL effects were on chromosomes 7AL and 7BL, due mainly to variation in grain numbers per ear. Three of the yield QTL clusters were largely site-specific, while four clusters were largely associated with one or other of the stress treatments. Three of the yield QTL clusters were coincident with the dwarfing gene Rht-B1 on 4BS and with the vernalisation genes Vrn-A1 on 5AL and Vrn-D1 on 5DL. Yields of each DHL were calculated for trial mean yields of 6 g plant(-1) and 2 g plant(-1) (equivalent to about 8 t ha(-1) and 2.5 t ha(-1), respectively), representing optimum and moderately stressed conditions. Analyses of these yield estimates using interval mapping confirmed the group-7 effects on yield and, at 2 g plant(-1), identified two additional major yield QTLs on chromosomes 1D and 5A. Many of the yield QTL clusters corresponded with QTLs already reported in wheat and, on the basis of comparative genetics, also in rice. The implications of these results for improving wheat yield stability are discussed.