Browsing by Author "Yin, Lu"
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Item Fine mapping coincident QTL on a chromosome 6H introgression region from unadapted germplasm into elite malting barley(2017-01) Yin, LuBreeders strive to improve a cultivar for multiple traits. This can be challenging when these traits are unfavorably associated. This study fine maps several traits associated with the centromeric region of chromosome 6H by mendelizing the region using near-isogenic lines (NILs). A NIL carrying an introgression from the landrace Chevron for this region was crossed to a malting cultivar Lacey to create 1941 F2 individuals from which recombinant NILs (rNILs) for the introgressed region were developed. We developed a dense genetic map using 249 F4-derived rNILs and phenotyped 101 of them in field and greenhouse trials for fourteen traits. We observed transgressive segregation for Fusarium head blight (FHB) severity, grain protein concentration (GPC), days to senescence, normalized difference vegetation index (NDVI), seedling net blotch, and heading date. We detected QTL for eleven traits. For ten of the traits, we detected multiple QTL with opposite allelic effects for each of them. Six traits that showed transgressive segregation mapped to multiple QTL with opposite allelic effects. QTL for deoxynivalenol (DON) accumulation mapped to separate regions to that for GPC and FHB severity, suggesting DON accumulation was likely associated through linkage rather than pleiotropy to GPC and FHB severity. While there was no recombinant line possessing all favorable alleles in this region, we identified two rNILs with numerically lower FHB severity and DON accumulation and GPC similar to Lacey. Seven traits (NDVI, days to senescence, percent stem breakage, GPC, heading date, adult net blotch severity and seedling net blotch severity) mapped to a single region, close to the physical location of the NAM-1/Gpc-1 gene. This gene is known to encode a NAC transcription factor that might be involved in nitrogen remobilization from leaves to grains during senescence. Findings in this study about coincident QTL controlling days to senescence, NDVI, percent stem breakage, and GPC might aid in the understanding of nitrogen remobilization process. Our fine mapping study revealed a complex genetic architecture for eleven traits associated with this chromosome 6H region and highlights the need for recombination to uncouple unfavorable linkages in breeding programs.Item Genetic understanding of resistance to foliar phylloxera, Daktulosphaira vitifoliae Fitch, in cold-hardy hybrid grapes(2020-06) Yin, LuPhylloxera is an important pest infesting foliage of North American native Vitis species and cold-hardy hybrids between V. vinifera and V. riparia. Currently, chemical control is the only commonly used management method. There is a need to development integrated pest management strategies including the use of resistant varieties (Chapter 1). The effects of foliar phylloxera infestations on four grape varieties were a numeric reduction in unit yield of cluster weight, photosynthesis rate, and photosystem II efficiency. This reduction in cluster weight can be economically important to growers (Chapter 2). Most genetic studies in grape for resistance to phylloxera limited to the root. A previous study using a population, GE1025 (N=~125), detected the first quantitative trait locus (QTL), a ~15-cM region, for foliar resistance on chromosome 14. To fine map the QTL, a larger population, GE1783 (N=~1023), was created and genotyped with the rhAmpSeq technology with conserved haplotype markers across Vitis species. Through selective phenotyping using a 0-7 severity rating scale among other phylloxera severity traits on 188 potential recombinants of GE1783, we fine mapped the QTL to 2.1-4.9 Mbp on chromosome 14. A most probable candidate resistance gene plays a role in gallic acid formation (Chapter 3). To investigate antixenosis as a possible resistance mechanism, leaf trichome density was mapped in GE1025 with genotype-by-sequencing and phenotypic scores collected using a 0-6 trichome density scale at several leaf positions. Evaluations were done on forced dormant cuttings in two years and on field-grown leaves in one year. There was a ~ -0.2 correlation (r) between trichome density and phylloxera resistance. Two regions on chromosomes 1 and 10 were repeatedly detected for multiple trichome density traits. We fine mapped the chromosome 1 QTL to a 140-kb region using selective phenotyping in GE1783. We found insertion/deletion variations of the parents of the population in one candidate pseudogene in this region and three other candidate genes proposed previously (Chapter 4). In all, we identified closely linked markers that can be used for marker-assisted breeding for foliar phylloxera resistance to improve the cold-hardy hybrid grape germplasm and potential candidate resistance genes for future investigations.Item Phenotypic and genotypic data of barley Gen10 population to study a pericentromeric region on chromosome 6H(2021-06-01) Yin, Lu; Huang, Yadong; Sallam, Ahmad; Heinen, Shane; Li, Lin; Beaubien, Karen; Dill-Macky, Ruth; Dong, Yanhong; Steffenson, Brian; Smith, Kevin; Muehlbauer, Gary; smith376@umn.edu; Smith, Kevin; University of Minnesota Barley Breeding and Genetics (Smith Lab)The phenotypic and genotypic data of the Gen10 population used to study a genetic region on chromosome 6H of barley associated with multiple traits. Gen10 is a population of ~100 Chevron-derived recombinant near-isogenic lines that contained the Fusarisum head blight/kernel discoloration resistance locus from Chevron, a landrace, in the genetic background of Lacey, an elite malting barley variety.Item Trichome density phenotypic data, image data, candidate genes Nanopore sequencing data(2020-08-13) Yin, Lu; Clark, Matthew; yinxx134@umn.edu; Yin, LuTwo experiments of phenotypic data on trichome density scores and sequencing data in a hybrid grape population (GE1025 family and GE1783 family). The excel file contains this data. Experiment 1 was conducted on greenhouse-maintained GE1025 cuttings in 2018 and 2019 and on field-grown leaves of GE1025 in 2019 (3 environments). Experiment 2 was conducted on GE1783 field-grown leaves in 2019 (1 environment). Experiment 1 was conducted under a dissecting scope. The images were where the trichome scores were obtained in Experiment 2. Nanopore sequencing data was part of Experiment 2. It is released now because it is under review for publication and it is needed to derive the conclusion for the fine mapped trichome region on chromosome 1 of hybrid grapes (Lu Yin's Ph.D. thesis in 2020 Chapter 4). This study on trichome offers information for hybrid grape breeding programs for a minor role in foliar phylloxera resistance.