Submitted to: Society of Nematologists Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: May 6, 2010
Publication Date: July 13, 2010
Citation: Roberts, P.A., Wang, C., Ulloa, M. 2010. Genetic and Physical Mapping of Meloidogyne Incognita Resistance on Chromosome 11 of Acala NemX Cotton. Society of Nematologists Proceedings. Page 102.
Root-knot nematode (RKN, Meloidogyne incognita) resistance in Gossypium hirsutum ‘Acala NemX’ cotton is conferred by the recessive gene rkn1 (locus Mi2h-C11) on chromosome 11. The concentration of RKN, reniform nematode and other disease resistance determinants on chromosome 11 indicates that much can be gained by molecular genetic and physical mapping analysis of this genomic region. Gene action analysis was conducted by inheritance and quantitative trait loci mapping of the RKN resistance in Acala NemX. Comparative analysis was conducted of the resistance in Acala NemX with RKN resistance in other Upland, Pima, and diploid cotton germplasm sources. The analysis was based on resistance segregation and expression in resistant x resistant and resistant x susceptible crosses, and on DNA sequence information of the multiple alleles of markers linked to RKN resistance and markers framing the chromosome 11 resistance region. The probable ancestral origin and introgression pathways of RKN resistance into the Acala NemX background were revealed, with results supporting artificial (man-made) introgression. Various crosses with RKN resistance sources indicated that allelic interaction, epistasis, and heterosis operate in the expression of resistance depending on resistance source and genetic background. In efforts to develop a physical framework of the resistance region, annotated complete sequence was developed of G. hirsutum ‘Acala Maxxa’ BAC clones anchored to chromosome 11 according to mapped BAC-end sequence derived markers (MUSB). The sequence information is being used to derive additional markers for screening combinatorial pools of an Acala NemX source (‘N901’) BAC library and for anchoring additional BACs in the resistance region.