Introgression Lines with Improved Resistance to Late Leaf Spot and Rust in Peanut

In an effort to simultaneously transfer and map the genomic regions governing resistance to late leaf spot (LLS) and rust in peanut, two susceptible varieties (lCGS 76 and OH 86) were crossed to two resistant synthetic tetraploids; an amphidiploid, ISATGR 278- 18 (Arachis duranensis x Arachis batizocoi) and an autotetraploid, ISATGR 5B (Arachis magna x Arachis batizocoi). Two cycles of backcrossing with the recurrent parents resulted in the development of a large number of introgression lines (ILs). They (BCl6 and BCl,) were evaluated during the rainy season of 2013 and 2014. ILs differed significantly for LLS and rust resistance, and productivity traits. Twenty seven introgression lines superior over lCGS 76, and three ILs superior over OH 86 for pod yield were selected from respective crosses. Many of them were highly resistant to both LLS and rust. Majority of them carried resistant allele at marker loci linked to LLS and rust. A few ILs also combined high test weight, shelling percentage and sound mature kernel percentage. Of these introgression lines, eleven were also superior over GPBO 4, a national check variety. These genetic resources can be of immense use in peanut breeding or for commercialization

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.)

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 × GPBD 4) and two backcross (DH 86 × ISATGR 278-18 and DH 86 × ISATGR 5) populations. GM1954, GM1009 and GM1573 markers showed significant association with LLS resistance. TAG 19 × GPBD 4 and ICGS 76 × ISATGR 278-18 populations showed strong co-segregation of LLS-linked 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