Status of Rice (Oryza sativa L.) Genepool Collected from Western Ghats Region of India: Gap Analysis and Diversity Distribution Mapping using GIS Tools

Abstract

This paper analyses the genetic resources of cultivated and wild rice in Western Ghats region (WGR) spread in six states of the country. Landraces and wild relatives of rice (Oryza sativa L.) always form a priority germplasm for exploration, collections, conservation, evaluation and utilization. Western Ghats region is one of the 35 biodiversity hot-spots of the world and harbour large diversity of rice under its varied climatic and edaphic conditions. So far, ICAR-NBPGR, New Delhi has collected 2, 758 accessions of cultivated and 49 of wild rice germplasm from 42 districts of WGR of India. Germplasm collecting sites linked with geo-coordinates forms geo-referenced map which showed that Kerala had significant representation (2, 036 accessions), followed by Karnataka (203), Maharashtra (201), Tamil Nadu (153), Gujarat (116) and Goa (49). Highest numbers of landraces were collected from Kerala (386), followed by Tamil Nadu (92), Karnataka (88), Gujarat (56), Goa (30) and Maharashtra (26). GIS-based grid map shows that highest numbers of landraces were collected from north and central regions of Kerala, validated by the highest Shannon-Weaver diversity index (2.1–2.8). Diverse agro-ecosystems as well as selection by farmers for various uses and traits, coupled with extensive exploration efforts might have lead to the assemblage of such landraces collection from Kerala. Collected wild rice germplasm consists six taxa -Oryza meyeriana var. granulata (11), O. nivara (4), O. officinalis (4), O. rufipogon (10), O. sativa f. spontanea (19) and O. officinalis subsp. malampuzhaensis (1). Literature analysis revealed that, out of 678 rice landraces of this region, 43 have been identified/used in crop improvement as source of important traits viz. early and late maturity, aroma, high iron content, medicinal value, drought/cold/salt tolerance, resistance to brown plant hopper, etc. This analysis identified gaps and priority areas for future explorations.