Screening of some diseases and root-knot nematode resistance genes by using molecular markers in groundnut germplasm and transferring resistant genes to advanced lines and cultivars

Groundnut or peanut is an important oilseed crop with high oil and protein content in seeds. This high-demanded crop is affected many biotic and abiotic stresses which limit its productivity and seed quality in tropic and sub-tropic areas of the world. Late leaf spot, rust, sclerotinia blight and root-knot nematodes are economically important biotic stress factors that and reduce the groundnut production. 256 groundnut genotypes were screened with molecular markers to identify resistant individuals against to such biotic stresses. The world groundnut mini core collection consisting of 186 genotypes was also evaluated as a part of collection. In molecular analyses, PCR products were separated in agarose gels and visualized under UV light after staining with ethidium bromide. Amplified products were also analyzed with the Fragment Analyzer™ which is high resolution bio-imaging system. Molecular results indicated that 142 genotypes associated with sclerotinia blight resistant marker in the collection. Among the resistant genotypes, 56 genotypes were from variety vulgaris, 54 genotypes were from variety fastigiata and 28 genotypes were from hypogaea. In the world groundnut mini core collection 115 genotypes showed the sclerotinia blight resistant banding pattern. The rust disease was evaluated with the SSR marker and 9 genotypes were identified as resistant after molecular analysis. 7 genotypes associated with rust resistant marker were also in world groundnut mini core collection. The resistant banding pattern related to the late leaf spot disease was observed in 15 genotypes from different botanical varieties. Among the resistant genotypes, 10 genotypes were from variety hypogaea, 2 genotypes were from variety fastigiata, 2 genotypes were from vulgaris, and 1 genotype was from variety hirsuta. In world groundnut mini core collection, 7 genotypes amplified resistant band following PCR amplification. The groundnut germplasm was also screened by the molecular marker related to root-knot nematode resistance. However no amplification was detected for all genotypes tested. Transferring the nematode resistance, nematode-resistant cultivars, COAN and NemaTAM, and susceptible cultivars, NC-7 and Florunner, were selected for hybridizations. In the present investigation, the most comprehensive study was carried out with molecular markers to reports new groundnut sources of resistance to important biotic stress factors.