Pyramiding and dissecting disease resistance QTL to barley stripe rust

Abstract

Quantitative resistance (QR) to disease is usually more durable than qualitative resistance, but its genetic basis is not well understood. We used the barley/barley stripe rust pathosystem as a model for the characterization of the QR phenotype and associated genomic regions. As an intermediate step in the preparation of near-isogenic lines representing individual QTL alleles and combinations of QTL alleles in a homogeneous genetic background, we developed a set of QTL introgression lines in a susceptible background. These intermediate barley near-isogenic (i-BISON) lines represent disease resistance QTL combined in one-, two-, and three-way combinations in a susceptible background. We measured four components of disease resistance on the i-BISON lines: latent period, infection efficiency, lesion size, and pustule density. The greatest differences between the target QTL introgressions and the susceptible controls were for the latter three traits. On average, however, the QTL introgressions also had longer latent periods than the susceptible parent (Baronesse). There were significant differences in the magnitudes of effects of different QTL alleles. The 4H QTL allele had the largest effect, followed by the alleles on 1H and 5H. Pyramiding multiple QTL alleles led to higher levels of resistance in terms of all components of QR except latent period.

Quantitative trait locus analysis of unsaturated fatty acids in a recombinant inbred population of soybean

“…The cumulative effects of QTL pyramiding have been proven previously in soybean (Li et al 2010;Njiti et al 2001Njiti et al , 2002 and in other crops (Huang et al 1997;Jiang et al 2007;Richardson et al 2006). Li et al (2010) analyzed Phytophthora root rot tolerance in a RIL population and evaluated the cumulative effects of the detected QTL.…”

Review Article: High-Temperature Adult-Plant Resistance, Key for Sustainable Control of Stripe Rust

“…Breeding programs have started using markers for the HTAP resistance QTL identified in Alpowa, Express, Stephens and Louise. Similarly, barley breeding programs have been using markers for the HTAP QTL in Bancroft [49] and those developed in Oregon State University for quantitative resistance to stripe rust on barley chromosomes 3H and 5H [101,102], presumably HTAP resistance. Molecular markers are even more useful for pyramiding HTAP QTL to achieve high levels of resistance.…”

Quantitative trait locus analysis of saturated fatty acids in a population of recombinant inbred lines of soybean

“…To enhance or improve a quantitatively inherited trait in plant breeding, pyramiding of multiple genes or QTL is recommended as a potential strategy (Richardson et al 2006). The cumulative effects of QTL pyramiding have been proved previously in soybean (Li et al 2010;Njiti et al 2001Njiti et al , 2002) and other crops (Huang et al 1997;Jiang et al 2007;Richardson et al 2006).…”