Identification of stable sources for surrogate traits in Arachis glabrata and marker-trait association for tolerance to water deficit stress

Diploid and tetraploid wild relatives of cultivated peanut are genetically diverse, providing rich sources of genetic resources for tapping resistance to various biotic and abiotic stresses. Arachis glabrata Benth. is a tetraploid (2n = 40) rhizomatous species that is reported to be tolerant to water deficit stress. Identification of A. glabrata accessions with high SPAD chlorophyll meter reading (SCMR) and low specific leaf area (SLA) values would be an option for improving water deficit stress tolerance in peanut. An investigation was undertaken to study the genetic diversity of A. glabrata accessions using molecular markers as well as surrogate traits (SLA and SCMR) for water deficit stress to identify stable sources for SCMR and to identify DNA markers linked to SCMR. SCMR showed high heritability and genetic advance as percent of mean (GAM) and a negative relation with SLA in A. glabrata. High heritability and high GAM indicates additive gene action. A high level of genetic diversity was observed in A. glabrata accessions, indicating that these populations had not experienced major genetic bottlenecks or genetic drift. Eight random amplified polymorphic DNA markers were identified with significant association to SCMR.