Skip to main content
ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #196074

Title: QTL mapping for resistance to root-knot nematodes in the M-120 RNR upland cotton line (Gossypium hirsutum L.) of the Auburn 623 RNR source

Author
item SHEN, XINLIAN - UNIVERSITY OF GEORGIA
item VAN BECELAERE, GUILLERMO - UNIVERSITY OF GEORGIA
item KUMAR, PAWAN - UNIVERSITY OF GEORGIA
item Davis, Richard
item MAY, O - UNIVERISTY OF GEORGIA
item CHEE, PENG - UNIVERSITY OF GEORGIA

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/18/2006
Publication Date: 9/8/2006
Citation: Shen, X., Van Becelaere, G., Guillermo, V.B., Kumar, P., Davis, R.F., May, O.L., Chee, P. 2006. QTL mapping for resistance to root-knot nematodes in the M-120 RNR upland cotton line (Gossypium hirsutum L.) of the Auburn 623 RNR source. Theoretical and Applied Genetics. 113:1539-1549.

Interpretive Summary: Root-knot nematodes can cause severe yield loss in cotton. The objectives of this study were to determine 1) whether the resistance genes from M-120 RNR germplasm (a highly resistant cotton line with nematode resistance from the Auburn 623 RNR source) are inherited in a dominant, recessive, or additive fashion, and 2) where in the cotton genome the resistance genes are located. The offspring from a cross between M-120 RNR and a susceptible Gossypium barbadense cultivar (Pima S-6) were studied, and the inheritance pattern indicated that a single dominant gene is responsible for most of the nematode resistance from this source. The entire cotton genome was scanned with DNA markers, and genetic regions were found to be linked to nematode resistance (one on Chromosome 7, and another on Linkage group A03). Additional analysis with another type of DNA marker confirmed a major dominant gene on Linkage group A03 and a minor gene on Chromosome 7. The major gene on Linkage group A03 was named Mi1-A03 had a very strong association with nematode resistance and was responsible for most of the nematode resistance measured in this study. The minor gene on Chromosome 7 was named Mi1-C07 and only accounted for a small amount of the resistance that was measured. The Mi1-A03 gene was shown to have come from the M-120 RNR parent, but the Mi1-C07 gene was shown to have come from the Pima S-6 parent. The Mi1-A03 gene, derived from Auburn 623 RNR germplasm, likely originated from the Clevewilt 6 cultivar, which was a parent of Auburn 623 RNR. This study indicates that one of the DNA markers we identified (an SSR marker named CIR316) may replace the laborious greenhouse screening currently used in breeding programs to identify genotypes resistant to the southern root-knot nematode.

Technical Abstract: Root-knot nematodes, Meloidogyne incognita (Kofoid and White), can cause severe yield loss in cotton (Gossypium hirsutum L.). The objectives of this study were to determine the inheritance and genomic location of genes conferring root-knot nematode resistance in M-120 RNR, a highly resistant G. hirsutum line with the Auburn 623 RNR source of resistance. Utilizing an interspecific F2 population developed from crossing M-120 RNR and a susceptible Gossypium barbadense cultivar (Pima S-6), inheritance analysis indicated that the data fits a single dominant gene model. Genome-wide scanning with RFLP markers revealed a marker on Chromosome 7 and two on Linkage group A03 showing significant association with the resistant phenotype. The association was confirmed using SSR markers with the detection of a minor and a major dominant QTL on Chromosome 7 and Linkage group A03, respectively. The major QTL on Linkage group A03 Mi1-A03 had a LOD score of 19.21 and accounted for 63.7% of the total phenotypic variation, while the minor QTL locus on Chromosome 7 Mi1-C07 had a LOD score of 3.48 and accounted for 7.7% of the total phenotypic variation. The allele from the M-120 RNR parent contributed to increased resistance in the Mi1-A03 locus, but surprisingly, the Pima S-6 allele contributed to increased resistance in the Mi1-C07 locus. The M-120 RNR allele in the Mi1-A03 locus, derived from Auburn 623 RNR, is likely to have originated from the Clevewilt 6 cultivar. Results from this study indicated that the SSR marker CIR316 may replace the laborious greenhouse screening in breeding programs to identify genotypes resistant to M. incognita.