SSR markers for marker assisted selection of root-knot nematode (Meloidogyne incognita) resistant plants in cotton (Gossypium hirsutum L)

Abstract

Cotton (Gossypium hirsutum L) cultivars highly resistant to the southern root-knot nematode (RKN) [Meloidogyne incognita (Kofoid and White) Chitwood] are not available. Resistant germplasm lines are available; however, the difficulty of selecting true breeding lines has hindered applied breeding and no highly resistant cultivars are available to growers. Recently, molecular markers on chromosomes 11 and 14 have been associated with RKN resistance, thus opening the way for marker assisted selection (MAS) in applied breeding. Our study aimed to determine the utility of these markers for MAS. Cross one was RKN resistant germplasm M240 RNR 9 the susceptible cultivar, FM966 and is representative of the initial cross a breeder would make to develop a RKN resistant cultivar. Cross two consists of Clevewilt 6 9 Mexico Wild (PI563649), which are the two lines originally used to develop the first highly RKN resistant germplasm. Mexico Wild is photoperiodic. We phenotyped the F 2 of cross one for gall index and number of RKN eggs per plant and genotyped each plant for CIR 316 (chromosome 11) and BNL 3661 (chromosome 14). From this, we verified that MAS was effective, and the QTL on chromosome 14 was primarily associated with a dominant RKN resistance gene affecting reproduction. In the first F 2 population of cross two, we used MAS to identify 11 plants homozygous for the markers on chromosomes 11 and 14, and which also flowered in long days. Progeny of these 11 plants were phenotyped for RKN gall index and egg number and confirmed as RKN highly resistant plants. Generally about 7-10 generations of RKN phenotyping and progeny testing were required to develop the original RKN highly resistant germplasms. Our results show that commercial breeders should be able to use the markers in MAS to rapidly develop RKN resistant cultivars. Keywords Cotton breeding Á Genetics Á Marker assisted breeding Á Plant breeding Á Root-knot nematode Abbreviations RKN Root-knot nematode MAS Marker assisted selection FM966 Fibermax cultivar SSR Simple sequence repeat BNL

Molecular Markers in Cotton Improvement

“…SSR markers namely CIR 316 tightly linked to Root knot nematod (RKN) resistant region on chromosome 11 and BNL 3661 marker tightly linked to RKN resistant region on chromosome 14. Jenkins et al, (2012) by using these SSR markers selected 11 homozygous plants for chromosome 11 and 14 from F2 population derived from RKN resistant genotype M 240 RNR ×susceptible cultivar FM966 instead of waiting up to F6-F8through conventional breeding. That selected plant confirmed resistance against the RKN.…”

Identification of microsatellite markers in coffee associated with resistance to Meloidogyne exigua

“…In soybean, Silva et al (2001) and Fuganti et al (2004) demonstrated an association between the microsatellite marker SOYHS 176 and the number of galls in Meloidogyne javanica, whereas Jenkins et al (2012) verified the association of microsatellite markers with the reaction to Meloidogyne incognita in cotton. However, in coffee, only an association between AFLP markers and resistance to the nematode species M. exigua has been reported (Noir et al, 2003;Diniz et al, 2005).…”

“…Molecular markers, such as microsatellites or simple sequence repeats (SSR), can be used to select progenies that are resistant to M. exigua as an alternative to the classic method of evaluation, which is both costly and time-consuming (Jenkins et al, 2012). If these markers are evaluated and validated in a population of coffee plants infested with nematodes, and their association with nematode resistance is established, they can be used to evaluate a high number of progenies in a short period.…”

Diversity of Meloidogyne incognita populations from cotton and aggressiveness to Gossypium spp. accessions

“…This line originated from the cross between two moderately resistant accessions: Clevewilt 6 and Wild Mexican Jack Jones (PI 593649). The quantitative trait locus (QTL) qMi‐C11, originating from Clevewilt 6, has an additive gene effect and is located in the CIR069–CIR316 interval on chromosome 11, whereas QTL qMi‐C14, which originated from Wild Mexican Jack Jones, has an additive‐dominant gene effect and is located in the BNL3545–BNL3661 interval on chromosome 14 (Shepherd, ; McPherson et al ., ; Jenkins et al ., ; He et al ., ). New sources of resistance are desirable for the development of cultivars with higher levels of resistance to this RKN and less likely to be supplanted by variants of the pathogen.…”