|WANG, CONGLI - Northeast Institute Of Geography And Agronomy, Cas|
|ROBERTS, PHILIP - Dominican University Of California|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/8/2014
Publication Date: 5/15/2014
Citation: Wang, C., Ulloa, M., Roberts, P.A. 2014. Transgressive segregation of root-knot nematode resistance in cotton determined by QTL analysis. [abstract]. In: Proceedings of 6th International Congress of Nematology, May 9, 2014, Cape Town, South Africa. 04092014:3.
Technical Abstract: Transgressive resistance to root-knot nematode, Meloidogyne incognita, was found in intraspecific (Gossypium hirsutum; resistant Acala NemX x susceptible Acala SJ-2) and interspecific (G. barbadense susceptible Pima-S7 x Acala NemX) cotton recombinant inbred line (RIL) populations. Similar contributions to both root-galling and egg-production resistance for SSR marker CIR316 linked to resistance gene rkn1 in NemX on chromosome 11 were identified in each population. Transgressive factor RKN2 from Pima-S7 clustered with rkn1 in NemX and produced higher resistance. QTL analysis of test-cross NemX x F1(Pima-S7 x SJ-2) showed Pima-S7 CIR069 (271 bp) allele marker linked to CIR316 contributed up to 63 percent of resistance to galling in the presence of rkn1. Similarly, on RIL Acala NemX x Acala SJ-2, markers closely linked to CIR316 contributed up to 82 percent of resistance to root-galling, indicating that interaction of factors from both susceptible and resistant parents occurred in the rkn1 resistance region. These results were confirmed in BC1F1 population Acala SJ-2 x F1 (NemX x SJ-2) and F2 population NemX x SJ-2, in which up to 44 percent and 37 percent increase in resistance to galling was found, respectively. These results indicated transgressive factor(s) from susceptible Acala SJ-2 exist in the region of rkn1, similar to transgressive factor RKN2 from susceptible Pima S-7, and stronger transgressive resistance occurred in later than in early generations in the intraspecific cross NemX x SJ-2. The complex recombination and interactions in the rkn1 resistance region in the Acala NemX background provides a model to study transgressive resistance in plants.