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• 1. [Article] Transfer, characterization and mapping of white mold resistance in an advanced backcross interspecific population between Phaseolus vulgaris and Phaseolus coccineus

  The advanced backcross-quatitative trait loci (AB-QTL) breeding method was employed on snap bean (OR 91G x PI433251B) and dry bean (M0162 x PI433251B) interspecific populations to transfer resistance QTL ...

  Citation × Citation Citation Abstract Copy Title: Transfer, characterization and mapping of white mold resistance in an advanced backcross interspecific population between Phaseolus vulgaris and Phaseolus coccineus Author: Zimmerman, Shawna Jean The advanced backcross-quatitative trait loci (AB-QTL) breeding method was employed on snap bean (OR 91G x PI433251B) and dry bean (M0162 x PI433251B) interspecific populations to transfer resistance QTL from resistant donor parent Phaseolus coccineus into P. vulgaris. For OR 91G x PI433251B, analyses produced nine linkage groups corresponding to eight core linkage groups for P. vulgaris consisting of 40 markers covering 336.7 cM (approximately 28.1% of the estimated bean genome). MQM mapping revealed one QTL that was located on linkage group Pv05 (LOD of 3.2) associated with 2009 percent field severity and accounted for 6.4% of the phenotypic variation. For M0162 x PI433251B, three linkage groups were observed, corresponding to three core linkage groups for P. vulgaris and consisted of 11 markers covering 42.44 cM (approximately 3.5% of the estimated bean genome). One QTL was identified with MQM mapping on linkage group Pv02 with a LOD of 1.8 and associated with the 2009 percent field severity, and accounted for 9.8% of the phenotypic variation. Because many SSR markers with known locations on previously published common bean linkage maps were unlinked, we constructed virtual maps to order polymorphic SSRs. In conjunction with single factor analysis and the Kruskall-Wallis analysis, probable locations of QTL were identified in the absence of the traditional QTL mapping. In addition to QTL mapping, trends for interspecific populations were investigated by comparing three different populations: the two populations being reported in this document for the first time (OR 91G x PI433251B and M0162 x PI433251B) and the previously analyzed OR 91G x PI255956. The general trends for interspecific populations were severe segregation distortion attributed to overrepresentation of heterozygotes, low marker polymorphism and regions of the genome that appear to recombine infrequently. Title: Transfer, characterization and mapping of white mold resistance in an advanced backcross interspecific population between Phaseolus vulgaris and Phaseolus coccineus Author: Zimmerman, Shawna Jean The advanced backcross-quatitative trait loci (AB-QTL) breeding method was employed on snap bean (OR 91G x PI433251B) and dry bean (M0162 x PI433251B) interspecific populations to transfer resistance QTL from resistant donor parent Phaseolus coccineus into P. vulgaris. For OR 91G x PI433251B, analyses produced nine linkage groups corresponding to eight core linkage groups for P. vulgaris consisting of 40 markers covering 336.7 cM (approximately 28.1% of the estimated bean genome). MQM mapping revealed one QTL that was located on linkage group Pv05 (LOD of 3.2) associated with 2009 percent field severity and accounted for 6.4% of the phenotypic variation. For M0162 x PI433251B, three linkage groups were observed, corresponding to three core linkage groups for P. vulgaris and consisted of 11 markers covering 42.44 cM (approximately 3.5% of the estimated bean genome). One QTL was identified with MQM mapping on linkage group Pv02 with a LOD of 1.8 and associated with the 2009 percent field severity, and accounted for 9.8% of the phenotypic variation. Because many SSR markers with known locations on previously published common bean linkage maps were unlinked, we constructed virtual maps to order polymorphic SSRs. In conjunction with single factor analysis and the Kruskall-Wallis analysis, probable locations of QTL were identified in the absence of the traditional QTL mapping. In addition to QTL mapping, trends for interspecific populations were investigated by comparing three different populations: the two populations being reported in this document for the first time (OR 91G x PI433251B and M0162 x PI433251B) and the previously analyzed OR 91G x PI255956. The general trends for interspecific populations were severe segregation distortion attributed to overrepresentation of heterozygotes, low marker polymorphism and regions of the genome that appear to recombine infrequently. Close

• 2. [Article] Characterization of physiological resistance to white mold and search for molecular markers linked to resistance via advanced backcross QTL analysis in an interspecific cross between Phaseolus coccineus and P. vulgaris

  White mold, caused by Sclerotinia sclerotiorum (Lib.) de Bary, results in severe losses in the production of common bean, Phaseolus vulgaris, especially snap bean varieties. Advanced backcross QTL analysis ...

  Citation × Citation Citation Abstract Copy Title: Characterization of physiological resistance to white mold and search for molecular markers linked to resistance via advanced backcross QTL analysis in an interspecific cross between Phaseolus coccineus and P. vulgaris Author: Haggard, Jack Erron White mold, caused by Sclerotinia sclerotiorum (Lib.) de Bary, results in severe losses in the production of common bean, Phaseolus vulgaris, especially snap bean varieties. Advanced backcross QTL analysis was used to identify quantitative trait loci for resistance to white mold in an interspecific cross of P. vulgaris and P. coccineus and to select resistant, well-adapted germplasm for development of superior common bean cultivars. A population of 115 BC2F4 lines from a cross of snap bean cultivar OR 91G x runner bean accession PI 255956 was genotyped using amplified fragment length polymorphism (AFLP®) and simple sequence repeat (SSR) markers. Corresponding BC2F5 progeny were evaluated for resistance to white mold in a greenhouse straw test and for tolerance to oxalate in a laboratory test. BC2F6 lines were then tested for resistance under field conditions. Single factor analysis of variance identified 29 marker loci contributing to response in at least one phenotypic test. One QTL conditioning 6% of the variance for field resistance was identified by composite interval mapping on linkage group 09, anchored to the consensus linkage group b09 by SSR loci. Significant deviation from expected segregation ratios was observed at all but 3 SSR loci and at all but 7 AFLP® loci (p < 0.05). Codominant SSR markers revealed excessive heterozygosity, and an underrepresented donor homozygous marker class. Several SSR markers polymorphic between parents failed to segregate in the progeny, particularly those corresponding to bean core map linkage groups b01, b04, and b05. Several lines were identified as possessing resistance superior to the recurrent parent. These will be incorporated into our efforts to produce highly resistant snap bean varieties. Title: Characterization of physiological resistance to white mold and search for molecular markers linked to resistance via advanced backcross QTL analysis in an interspecific cross between Phaseolus coccineus and P. vulgaris Author: Haggard, Jack Erron White mold, caused by Sclerotinia sclerotiorum (Lib.) de Bary, results in severe losses in the production of common bean, Phaseolus vulgaris, especially snap bean varieties. Advanced backcross QTL analysis was used to identify quantitative trait loci for resistance to white mold in an interspecific cross of P. vulgaris and P. coccineus and to select resistant, well-adapted germplasm for development of superior common bean cultivars. A population of 115 BC2F4 lines from a cross of snap bean cultivar OR 91G x runner bean accession PI 255956 was genotyped using amplified fragment length polymorphism (AFLP®) and simple sequence repeat (SSR) markers. Corresponding BC2F5 progeny were evaluated for resistance to white mold in a greenhouse straw test and for tolerance to oxalate in a laboratory test. BC2F6 lines were then tested for resistance under field conditions. Single factor analysis of variance identified 29 marker loci contributing to response in at least one phenotypic test. One QTL conditioning 6% of the variance for field resistance was identified by composite interval mapping on linkage group 09, anchored to the consensus linkage group b09 by SSR loci. Significant deviation from expected segregation ratios was observed at all but 3 SSR loci and at all but 7 AFLP® loci (p < 0.05). Codominant SSR markers revealed excessive heterozygosity, and an underrepresented donor homozygous marker class. Several SSR markers polymorphic between parents failed to segregate in the progeny, particularly those corresponding to bean core map linkage groups b01, b04, and b05. Several lines were identified as possessing resistance superior to the recurrent parent. These will be incorporated into our efforts to produce highly resistant snap bean varieties. Close

• 3. [Article] Pyramiding quantitative trait loci conditioning partial resistance to Sclerotinia sclerotiorum in bush blue lake green beans (Phaseolus vulgaris)

  Sclerotinia sclerotiorum (Lib.) de Bary is a necrotrophic pathogen capable of causing white mold, a severe disease in common bean. White mold is of particular concern to the Oregon snap bean processing ...

  Citation × Citation Citation Abstract Copy Title: Pyramiding quantitative trait loci conditioning partial resistance to Sclerotinia sclerotiorum in bush blue lake green beans (Phaseolus vulgaris) Author: Barrett, Miles Andrew Sclerotinia sclerotiorum (Lib.) de Bary is a necrotrophic pathogen capable of causing white mold, a severe disease in common bean. White mold is of particular concern to the Oregon snap bean processing industry, where processors allow less than 3% incidence in harvested shipments. Breeding for white mold resistance in beans has been difficult due to quantitative inheritance and low heritability. We combined two quantitative trait loci (QTL) for physiological resistance to white mold: a QTL located on linkage group 7 from G122 and a B8 QTL from NY6020. The B7 QTL is linked to phaseolin for which a sequence characterized amplified region (SCAR) marker phaseolin has been used successfully to transfer the QTL in dry bean. The transfer in snap bean is more challenging because this QTL is also linked to the p locus which conditions the white-seeded trait. While most snap beans have T phaseolin seed protein, the OSU bush blue lake (BBL) materials have the S form of phaseolin, facilitating the use of T phaseolin as a selectable marker in breeding for white mold resistance. Thus, transfer of this QTL has to be coupled with breaking the linkage between colored seed and the resistance QTL. The B8 QTL is linked to the SS18₁₆₅₀ SCAR and AW19₁₂₀₀ random amplified polymorphic DNA (RAPD) markers. Oregon State University BBL bean germplasm originally developed with single QTL were crossed to pyramid the two resistance QTL. The assumptions made in combining these two sources of resistance are that the QTL are non-allelic and are additive. OSU 6229, OSU 6230, and OSU 6241 are advanced breeding lines that have the SS18₁₆₅₀ allele from NY6020 and show statistically significant higher levels of resistance in the field and greenhouse (straw) test compared to susceptible cultivars. White-seeded, T phaseolin types were selected from a OR 91G x G122 BC₂F₃ population. The selected lines showed levels of resistance significantly better than the susceptible check cultivars in the straw test. The two sources were crossed and the progeny were subjected to three or more generations of phenotypic selection in the straw test. One hundred and forty eight families were planted in a randomized complete block design (RCBD). All families had been previously genotyped using the PHAS and SS18₁₆₅₀ SCAR molecular markers. Plants were inoculated using actively growing mycelium of S. sclerotiorum and scored using a modified straw test to test for genetic additivity among marker classes. None of the lines were statistically more resistant than G122, a QTL donor and standard resistant check. In a separate study, data collected in NY6020-5 x OR 91G and NY6020-5 x OSU 5613 populations suggest that NY6020-5 has a B7 QTL equivalent to G122. Other researchers have presented evidence that G122 has a B8 QTL equivalent to NY6020. Finally in a mixed linear model study we identified two markers, B18₁₅₀₀ and C8₁₂₀₀, which should prove useful in breeding for white mold resistance. While the material that we developed does not show significantly higher levels of resistance than the resistant parents, we have transferred the resistance QTL into a bush blue lake background, and the lines derived from this work should have significantly higher levels of resistance than existing commercial cultivars. We also present evidence of a QTL not previously identified in NY6020-5. Title: Pyramiding quantitative trait loci conditioning partial resistance to Sclerotinia sclerotiorum in bush blue lake green beans (Phaseolus vulgaris) Author: Barrett, Miles Andrew Sclerotinia sclerotiorum (Lib.) de Bary is a necrotrophic pathogen capable of causing white mold, a severe disease in common bean. White mold is of particular concern to the Oregon snap bean processing industry, where processors allow less than 3% incidence in harvested shipments. Breeding for white mold resistance in beans has been difficult due to quantitative inheritance and low heritability. We combined two quantitative trait loci (QTL) for physiological resistance to white mold: a QTL located on linkage group 7 from G122 and a B8 QTL from NY6020. The B7 QTL is linked to phaseolin for which a sequence characterized amplified region (SCAR) marker phaseolin has been used successfully to transfer the QTL in dry bean. The transfer in snap bean is more challenging because this QTL is also linked to the p locus which conditions the white-seeded trait. While most snap beans have T phaseolin seed protein, the OSU bush blue lake (BBL) materials have the S form of phaseolin, facilitating the use of T phaseolin as a selectable marker in breeding for white mold resistance. Thus, transfer of this QTL has to be coupled with breaking the linkage between colored seed and the resistance QTL. The B8 QTL is linked to the SS18₁₆₅₀ SCAR and AW19₁₂₀₀ random amplified polymorphic DNA (RAPD) markers. Oregon State University BBL bean germplasm originally developed with single QTL were crossed to pyramid the two resistance QTL. The assumptions made in combining these two sources of resistance are that the QTL are non-allelic and are additive. OSU 6229, OSU 6230, and OSU 6241 are advanced breeding lines that have the SS18₁₆₅₀ allele from NY6020 and show statistically significant higher levels of resistance in the field and greenhouse (straw) test compared to susceptible cultivars. White-seeded, T phaseolin types were selected from a OR 91G x G122 BC₂F₃ population. The selected lines showed levels of resistance significantly better than the susceptible check cultivars in the straw test. The two sources were crossed and the progeny were subjected to three or more generations of phenotypic selection in the straw test. One hundred and forty eight families were planted in a randomized complete block design (RCBD). All families had been previously genotyped using the PHAS and SS18₁₆₅₀ SCAR molecular markers. Plants were inoculated using actively growing mycelium of S. sclerotiorum and scored using a modified straw test to test for genetic additivity among marker classes. None of the lines were statistically more resistant than G122, a QTL donor and standard resistant check. In a separate study, data collected in NY6020-5 x OR 91G and NY6020-5 x OSU 5613 populations suggest that NY6020-5 has a B7 QTL equivalent to G122. Other researchers have presented evidence that G122 has a B8 QTL equivalent to NY6020. Finally in a mixed linear model study we identified two markers, B18₁₅₀₀ and C8₁₂₀₀, which should prove useful in breeding for white mold resistance. While the material that we developed does not show significantly higher levels of resistance than the resistant parents, we have transferred the resistance QTL into a bush blue lake background, and the lines derived from this work should have significantly higher levels of resistance than existing commercial cultivars. We also present evidence of a QTL not previously identified in NY6020-5. Close