Liu, Xiaoyu , Reighard, Gregory , Swire-Clark, Ginger , Bridges, William , Abbott, Albert , Baird, Wm. Vance .
Identification of chromosomal regions associated with tolerance to Peach Tree Short Life, a serious disease syndrome of Prunus persica (L.) Batsch (Rosaceae).
Peach Tree Short Life (PTSL) is a complicated disease syndrome involving nematodes, soil conditions, pruning and secondary pathogens. The disease occurs commonly in the southeastern U.S, and possibly in other areas of the US, Europe, South America and South Africa as the related Bacterial Canker Complex. PTSL causes premature tree death during the 3rd or 4th year, resulting in large economic losses. Recently GuardianÂ® ‘BY520-9’ rootstock was selected for its tolerance to PTSL; however, the genetic basis for tolerance is unknown. Nemaguard, a PTSL susceptible rootstock, and GuardianÂ® selection 3-17-7 were crossed. Each F1 plants was selfed to create segregating F2 populations (e.g., F1-11 has 100 F2 trees, replicated three times). The trees have been rated for their response to PTSL since 2004. Genomic DNA was purified from leaf tissue. One hundred and seventy microsatellite/Simple Sequence Repeat (SSR) markers, uniquely mapped to chromosomal locations on the Prunus reference genome, were used to screen the parents and F1-11. Only forty-seven SSR markers showed polymorphism among the parents, and were heterozygous in F1-11. These SSRs were then screened on F2-11. Segregation data for PTSL-response and SSR marker inheritance were compiled and subjected to Analysis of Variance to determine differences in genotype means. The results indicated that 25 SSR loci co-segregate with PTSL response, because the genotype means show significant difference in PTSL rating. These 25 SSR loci are unevenly distributed across the 8 chromosomes, such that chromosome 2 has the most SSR loci (6), and chromosome 6, 7 and 8 have the fewest (1). These results identify regions of the peach genome where genes controlling PTSL susceptibility and tolerance reside, thus helping to define the genetic basis for response to PTSL. Year five phenotype data will be collected and incorporated this spring to improve sensitivity and resolution of the analysis.
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1 - Clemson University, Horticulture Department, Poole Agriculture Center, Clemson, SC, 29634-0319, U.S.A.
2 - Clemson University, Horticulture
3 - Clemson University, Applied Economics and Statistics, 29634-0313
4 - Clemson University, Genetics and Biochemistry, 29634-0318
5 - Clemson University, Horticulture and Environmental Toxicology
Presentation Type: Poster:Posters for Sections
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM