Validation of markers linked to late leaf spot and rust resistance, and selection of superior genotypes among diverse recombinant inbred lines and backcross lines in peanut (Arachis hypogaea L.)

Abstract

Recombinant inbred lines (RILs) from four populations involving cultivated varieties, and backcross lines from three populations involving cultivated varieties and synthetic tetraploids (developed from wild diploids) were employed for validating late leaf spot (LLS) and rust resistance-linked markers and identifying superior genotypes in peanut. GM2009, GM2301, GM2079, GM1536, GM1954 and IPAHM103 markers showed significant association with rust resistance. They were successfully validated in a new RIL (TG 19 9 GPBD 4) and two backcross (DH 86 9 ISATGR 278-18 and DH 86 9 ISATGR 5) populations. GM1954, GM1009 and GM1573 markers showed significant association with LLS resistance. TAG 19 9 GPBD 4 and ICGS 76 9 ISATGR 278-18 populations showed strong co-segregation of LLSlinked markers with the phenotype. From these genetic resources, six superior genotypes were identified. RIL 78-1 was resistant to LLS and rust, and recorded 30 % more pod yield than GPBD 4 (control). It also had higher kernel yield and oil yield along with higher oleate and linoleate content over GPBD 4. These genetic and genomic resources could be useful in breeding for LLS and rust resistance in peanut.

Advancements in molecular marker development and their applications in the management of biotic stresses in peanuts

“…Several studies have emphasized the application of different types of molecular markers, construction of peanut linkage maps, or tagging of important agronomic traits, such as disease resistance Gajjar et al, 2014). Recently, many DNA markers have been found to be putatively linked to rust and LLS resistance genes (Mondal et al, 2012a;Khedikar et al, 2010;Shoba et al, 2012;Sujay et al, 2012) (Table 2), a few of which have been validated and used in the breeding programme Gajjar et al, 2014;Varshney et al, 2014). Location of markers on the various linkage groups in Table 2, is derived after doing intensive meta-analysis of all the published literature, including the most comprehensive and consensus linkage maps available in peanut.…”

“…The search for peanut cultivars resistant to S. rolfsii originates all the way back Table 1 List of a few genotypes, used for mapping of various resistance gene(s) (Dwivedi et al, 2003;Shoba et al, 2012;Sujay et al, 2012). to 1918(McClintock, 1918, but a high degree of resistance is yet to be found.…”

“…The majority of the identified QTLs are not major and account for less than 10% of the phenotypic variation explained (PVE). Major QTLs identified for rust and LLS in the germplasm source (Khedikar et al, 2010;Sujay et al, 2012) and for nematode resistance (Nagy et al, 2010;Simpson, 2001) were of a wild species origin.…”

“…Through validating LLS and rust resistance-linked markers in different peanut genotypes, six superior genotypes were identified. Moreover, three lines that are superior for productivity traits and equal for disease resistance to GPBD 4 (the resistant parent) are being included in variety release trials for multi-location evaluation (Sukruth et al, 2015). Gajjar et al (2014) studied 22 SSR markers reportedly linked to rust and LLS disease resistance on 95 diverse genotypes for marker validation, from which 16 SSRs could be validated.…”

Mapping QTLs for Leafspot Resistance in Peanut Using SNP-Based Next-Generation Sequencing Markers

“…Previous reports indicated that leafspot resistance is controlled by multiple genes (Green and Wynne 1986) and several QTLs for tolerance to this disease identified using SSR markers have been reported in various RIL populations (Khedikar et al 2010;Sujay et al 2012;Wang et al 2013;Sukruth et al 2015). The objective of our current study is to precisely map QTLs conferring peanut leafspot resistance using high density sequence-based SNP marker genotyping by double digest restriction-site associated DNA sequencing (ddRAD-seq) (Baird et al 2008;Peterson et al 2012).…”