http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Mapping of verticillium wilt resistance genes in cotton
xiii, 113 leaves : illustrations ; 28 cm.
Cotton (Gossypium spp.) is one of the world's important cash crops. Cotton quality and yield are affected by several factors during the growing season. A soil inhabiting fungus, Verticillium dahliae Kleb., can cause substantial yield loss in cotton. A molecular mapping population derived from the interspecific cross of the resistant cv Pima S-7 (G. barbadense) and the susceptible cv Acala 44 (G. hirsutum) was phenotyped for disease incidence and severity. Phenotyping of plant reaction to the disease was quantified using a set of growth parameters measured three weeks after inoculation. The F₂ phenotypic distribution of these parameters (number of healthy leaves, number of nodes, leaf weight, stem weight, leaf to stem ratio, and total shoot weight) suggests that resistance is polygenic. Microsatellites were used to reveal polymorphism between resistant and susceptible parents. A total of 255 simple sequence repeat (SSR) primer pairs obtained from three sources, JESPR, CM and BNL were screened over bulks representing resistant and susceptible phenotypes. Sixty markers were used to analyze quantitative trait loci (QTLs). Eleven linkage groups were constructed consisting of 35 markers and spanning 531 cM with an average distance of 15.17 cM. QTL analysis was performed using three different programs: QGene, MapQTL, and QTL Cartographer. Using QGene, 27 molecular markers were linked to disease resistance (total of 6 traits); 16 were distributed on chromosomes 7, 10, 11, 12, and 25. MapQTL indicated that 16 markers have significant linkage associations, and 9 were distributed to chromosomes 10, 11, 12, and 25. Interval mapping also indicated the most likely position of markers that are significant and located on linkage groups. Seven QTLs were revealed by interval mapping: three on LG-1 nearer to CM12, STS1, and BNL1053-1, one on LG-2 nearer to NEJ6, one on LG-3 nearer to BNL3147-1, one in LG-4 nearer to JESPR231-1, and one in LG-8 nearer to BNL3379. The TM-1 x 3-79 population map also confirmed three QTLs mapped to the same region. QTLs were found 0.9 to 15 cM away from the markers that could have potential for DNA marker-assisted selection to enhance resistance to Verticillium wilt in superior cotton cultivars.
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Includes bibliographical references (leaves 84-90).