Submitted to: Society of Nematologists Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 3/28/2011
Publication Date: 7/17/2011
Citation: Wang, C., Mullens, T.R., Ulloa, M., Roberts, P.A. 2011. QTL analysis for transgressive resistance to root-knot nematode in a cotton RIL population derived from interspecific susceptible parents (Gossypium spp.). Society of Nematologists Annual Meeting, August 12 to 16, 2011, Savannah, Georgia. p. 106. Interpretive Summary:
Technical Abstract: The root-knot nematode (RKN, Meloidogyne incognita) is a major parasite of cotton, causing significant yield losses in most production areas. A genetic standard recombinant inbred population of 138 lines developed from a cross between Upland cotton TM-1 (Gossypium hirsutum L.) and Sea island cotton Pima 3-79 (G. barbadense L.), both susceptible to RKN, was used to identify responses to RKN in two greenhouse experiments. Compared to both parents, 50.7% and 51.4% of lines showed less galling index and lower nematode egg production, respectively. Highly resistant lines were identified in the RIL population. Four quantitative trait loci (QTLs) accounting for 7.2 to 13% of the phenotypic variance (R2) in galling index, and two QTLs accounting for 6.7% and 8.4% of the egg production variance were identified based on interval mapping (LOD score =2) and Kruskal-Wallis (KW) analysis (P = 0.005). These QTLs were located on chr3, 4 and 17 for galling index and chr14 and chr23 for egg production. In addition, 15 putative QTLs accounting for 3.8% to 5.8% (2>LOD=1 and P = 0.05) of phenotypic variance in galling index, and 12 QTLs accounting for 3.2% to 5.2% in egg production variance were identified. In lines with combinations of 2 to 5 QTLs with positive alleles from both parents, reductions of >50% in both root galling and egg production were recorded. These epistatic effects in progeny derived from susceptible parents indicate that pyramiding of these QTLs may present a high level of nematode resistance in cotton.