|
| ||
|
|
||
Bulked Segregant Analysis (bulked + segregant_analysis)
Selected AbstractsIdentification of novel QTL for resistance to crown rot in the doubled haploid wheat population ,W21MMT70' × ,Mendos'PLANT BREEDING, Issue 6 2006W. D. Bovill Abstract Crown rot (causal agent Fusarium pseudograminearum) is a fungal disease of major significance to wheat cultivation in Australia. A doubled haploid wheat population was produced from a cross between line ,W21MMT70', which displays partial seedling and adult plant (field) resistance to crown rot, and ,Mendos', which is moderately susceptible in seedling tests but partially resistant in field trials. Bulked segregant analysis (BSA) based on seedling trial data did not reveal markers for crown rot resistance. A framework map was produced consisting of 128 microsatellite markers, four phenotypic markers, and one sequence tagged site marker. To this map 331 previously screened AFLP markers were then added. Three quantitative trait loci (QTL) were identified with composite interval mapping across all of the three seedling trials conducted. These QTL are located on chromosomes 2B, 2D and 5D. The 2D and 5D QTL are inherited from the line ,W21MMT70', whereas the 2B QTL is inherited from ,Mendos'. These loci are different from those associated with crown rot resistance in other wheat populations that have been examined, and may represent an opportunity for pyramiding QTL to provide more durable resistance to crown rot. [source] Isolation of a Novel Tomato Caffeoyl CoA 3- O -methyltransferase Gene Following Infection with the Bacterium Ralstonia solanacearumJOURNAL OF PHYTOPATHOLOGY, Issue 10 2008L. Miao Abstract We combined cDNA amplified fragment length polymorphism (cDNA-AFLP) with bulked segregant analysis (BSA) to detect genes that control tomato (Lycopersicon esculentum) bacterial wilt infected with Ralstonia solanacearum, resistance in F2 population derived from a cross between a bacterial wilt-resistant variety, T51A, and a bacterial wilt-susceptible variety, T9230. In cDNA-AFLP analysis among bulked-resistant F2 (BR) pool, bulked-susceptible F2 (BS) pool, bulked-resistant T51A (BA) pool and bulked-susceptible T9230 (BB) pool, 34 differentially expressed transcript-derived fragments (DE-TDFs) that were present in only BR and BA pools were detected. Analysis of differential DE-TDF expression in individual resistant F2 resulted in the isolation of a caffeoyl CoA 3- O -methyltransferase (CCoAOMT) gene not previously described from tomato and which showed similarity to an CCoAOMT gene from tobacco and potato plants. This CCoAOMT gene may play a role in innate generalized response to pathogen infection as it was downregulated in susceptible tomato following infection with the bacterium. CCoAOMT gene plays an essential role in the synthesis of guaiacyl lignin units and supply substrates for the synthesis of syringyl lignin units. [source] Identification of a SCAR marker linked to a recessive male sterile gene (Tems) and its application in breeding of marigold (Tagetes erecta)PLANT BREEDING, Issue 1 2009Y. H. He Abstract In marigold, an F2 segregation population of 167 plants was constructed from a cross of a line (M525A) carrying the male sterility trait × an inbred line (f53f). In line M525A, the male sterility trait was controlled by the recessive gene, Tems. The intersimple sequence repeat (ISSR) and sequence-related amplified polymorphism (SRAP) techniques combined with bulked segregant analysis were used to develop markers linked to the trait. From a survey of the 38 ISSR primers and 170 SRAP primer combinations, only one SRAP marker that was closely linked to the target trait was identified and successfully converted into sequence characterized amplified region (SCAR) marker that was located within 2.4 cM from Tems locus. The marker was validated with five other two-type lines and in each case the male fertile plants were reliably identified. This SCAR marker therefore permits the efficient marker-assisted selection of male sterile individuals in breeding programmes of marigold and will greatly facilitate the breeding of F1 cultivars. [source] Development of molecular markers for crown rot resistance in wheat: mapping of QTLs for seedling resistance in a ,2-49' × ,Janz' populationPLANT BREEDING, Issue 6 2005B. C. Y. Collard Abstract Crown rot, caused by Fusarium pseudograminearum, is an important disease of wheat in Australia and elsewhere. In order to identify molecular markers associated with partial seedling resistance to this disease, bulked segregant analysis and quantitative trait loci (QTL) mapping approaches were undertaken using a population of 145 doubled haploid lines constructed from ,2-49' (partially resistant) × ,Janz' (susceptible) parents. Phenotypic data indicated that the trait is quantitatively inherited. The largest QTLs were located on chromosomes 1D and 1A, and explained 21% and 9% of the phenotypic variance, respectively. Using the best markers associated with five QTLs identified by composite interval mapping, the combined effect of the QTLs explained 40.6% of the phenotypic variance. All resistance alleles were inherited from ,2-49' with the exception of a QTL on 2B, which was inherited from ,Janz'. A minor QTL on 4B was loosely linked (19.8 cM) to the Rht1 locus in repulsion. None of the QTLs identified in this study were located in the same region as resistance QTLs identified in other populations segregating for Fusarium head blight, caused by Fusarium graminearum. [source] | ||||||||||