Marker-assisted backcross breeding in wheat.

摘要

Restriction fragment length polymorphism (RFLP) markers can be converted to sequence-tagged-site (STS) primer sets recognized by the polymerase chain reaction (PCR). STS-PCR markers were mapped in wheat and barley to evaluate the correspondence of chromosome locations between species and with the mapped RFLPs. STS amplification products in wheat mapped to the same chromosome as the RFLP approximately 70% of the time. Barley STS location corresponded to the RFLP location approximately 60% of the time. RFLP mapping information was transferable 82% of the time between wheat and barley with STS information transferable 74% of the time. Multiple STS locations were generally mapped in wheat. Southern analysis was used to evaluate the homology of the amplification products to the RFLP clone. Homologous sequences were generally amplified, but non-homologous sequences were also amplified in some cases. The results indicate that STS information can be transferred between wheat and barley, and that RFLP location could provide an indication of the STS location in both wheat and barley. However, amplification of unmapped RFLP locations and non-homologous sequences is a factor to consider in their application.; The potential of STS markers as an aid in selection for the recurrent parent in a backcross breeding program to introgress Russian wheat aphid resistance into wheat was also investigated. Three recombinant inbred populations were established from crosses between a Russian wheat aphid resistant line, PI372129, and two Montana hard red spring wheat cultivars, Pondera and Newana, in order to evaluated the level of donor genome and potential correlations with phenotypic performance. The percentage of donor genome, based on marker analysis, varied between the lines within the populations. Significant positive correlations between percentage of donor genome with plant height and straw strength were observed for the Pondera single cross population. No significant correlations were observed for the two backcross populations. The backcross population means approached that of the recurrent pattern with a decrease in the number of lines significantly different from the recurrent parent. Results suggests that molecular marker could be used to select for the recurrent parent genotype, and provide optimism for marker-assisted selection to recover the recurrent parent phenotype.