Quantitative trait locus analysis of Verticillium wilt resistance in an introgressed recombinant inbred population of Upland cotton

Authors: FANG, HUI - New Mexico State University; ZHOU, HUIPING - New Mexico State University; SANOGO, SOUM - New Mexico State University; LIPKA, ALEXANDER - Cornell University; Fang, David; Percy, Richard; Hughs, Sidney; JONES, DON - Cotton, Inc; GORE, MICHAEL - Cornell University; ZHANG, JINFA - New Mexico State University

Submitted to: Molecular Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/5/2013
Publication Date: 2/28/2014
Citation: Fang, H., Zhou, H., Sanogo, S., Lipka, A.E., Fang, D.D., Percy, R.G., Hughs, S.E., Jones, D.C., Gore, M.A., Zhang, J. 2014. Quantitative trait locus analysis of Verticillium wilt resistance in an introgressed recombinant inbred population of Upland cotton. Molecular Breeding. 33:709-720.

Interpretive Summary: Verticillium wilt (VW) is an important fungal disease that causes significant yield loss to the US cotton production especially in Texas and western states. VM is caused by the soil-borne pathogen Verticillium dahlia Kleb. It is very difficult to control this disease using conventional production practices. The availability of VW-resistant cultivars is vital to control this disease, but there is very limited upland cotton lines with a high level of resistance to VW. In general, G. barbadense L. (source of Pima cotton) is more VW-resistant than upland cotton. However, the transfer of VW resistance from G. barbadense to upland cotton is challenging because of hybrid breakdown in the F2 and successive generations of interspecific populations. We conducted two replicated greenhouse studies to assess the heritability of VW resistance to a defoliating V. dahliae isolate and identify genetic markers associated with VW resistance in an upland cotton recombinant inbred mapping population that has stable introgression from Pima cotton. Disease ratings at the seedling stage on several different days after the first inoculation (DAI) in test 1, as well as the percentages of infected and defoliated leaves at two DAI in test 2 were found to be low to moderately heritable. With a newly constructed linkage map consisting of 882 simple-sequence repeat (SSR), single-nucleotide polymorphism (SNP), and resistance gene analog-amplified fragment length polymorphism (RGA-AFLP) marker loci, we identified a total of 21 QTLs on 11 chromosomes and two linkage groups associated with VW resistance at several different DAIs in greenhouse tests 1 and 2. The markers associated with the VW resistance QTLs will facilitate fine mapping and cloning of VW resistance genes and genomics-assisted breeding for VW resistant cultivars.

Technical Abstract: Verticillium wilt (VW) of Upland cotton (Gossypium hirsutum L.) is caused by the soil-borne fungal pathogen Verticillium dahlia Kleb. The availability of VW-resistant cultivars is vital for control of this economically important disease, but there is a paucity of Upland cotton breeding lines and cultivars with a high level of resistance to VW. In general, G. barbadense L. (source of Pima cotton) is more VW-resistant than Upland cotton. However, the transfer of VW resistance from G. barbadense to Upland cotton is challenging because of hybrid breakdown in the F2 and successive generations of interspecific populations. We conducted two replicated greenhouse studies (tests 1 and 2) to assess the heritability of VW resistance to a defoliating V. dahliae isolate and identify genetic markers associated with VW resistance in an Upland cotton recombinant inbred mapping population that has stable introgression from Pima cotton. Disease ratings at the seedling stage on several different days after the first inoculation (DAI) in test 1, as well as the percentages of infected and defoliated leaves at two DAI in test 2 were found to be low to moderately heritable. With a newly constructed linkage map consisting of 882 simple-sequence repeat (SSR), single-nucleotide polymorphism (SNP), and resistance gene analog-amplified fragment length polymorphism (RGA-AFLP) marker loci, we identified a total of 21 QTLs on 11 chromosomes and two linkage groups associated with VW resistance at several different DAIs in greenhouse tests 1 and 2. The markers associated with the VW resistance QTLs will facilitate fine mapping and cloning of VW resistance genes and genomics-assisted breeding for VW resistant cultivars.