Phenotypic diversity and identification of wild Arachis accessions with useful agronomic and nutritional traits

Abstract

Wild relatives harbor novel sources of variation, which can be used to enhance the genetic base of a cultivar gene pool. A total of 269 accessions from 20 wild Arachis species belonging to six sections were evaluated for 41 morpho-agronomic traits and 89 selected accessions for oil, protein and total sugar content. Six plants from each accession were grown in an open Arachis house in large-cylindrical concrete structures during the 2004–2005 season at Patancheru, India. REML analysis showed significant differences between species and accessions for most of the traits studied. Hierarchical cluster analysis, based on the first five principal component scores accounted for 82.5% variation, resulting in four clusters. Variation in genome relationships and ploidy levels had no bearing on the clustering pattern which was predominated by life forms: clusters 1 and 2, contained mostly annuals and clusters 3 and 4 perennials. A large range of variations were noticed among species for some of the agronomic traits: days to flowering, pod and seed characteristics, specific leaf area (SLA) and for SPAD chlorophyll meter reading (SCMR). Arachis duranensis showed the maximum intraspecific variation as revealed by a high diversity index for 23 of the 41 traits which included: days to flowering, primary branches, plant width, pod length, pod width, SCMR and SLA. The other species with desirable traits were A. pusilla (earliest flowering) and A. villosa (high SCMR at 60 and 80 days after sowing). The latter species is cross compatible with cultivated groundnut, thus, is a good source to enhance the trait value in the cultigen’s gene pool. The best 20 accessions with superior agronomic, nutritional quality and drought related trait combinations have been identified for their use in introgression of diverse and unique alleles from wild Arachis species into A. hypogaea.