Rice landrace diversity in Nepal: Variability of agro-morphological traits and SSR markers in landraces from a high-altitude site
Authors: Jwala Bajracharya, K.A. Steele, Devra I. Jarvis, Bhuwon Ratna Sthapit, John Witcombe
Field Crops Research, Volume 95, Issues 2–3, 15 February 2006, Pages 327–335
Nepal has a wide diversity of rice landraces in all rice-growing areas from low to high altitude. A baseline survey in Jumla, a high-altitude site (2200–3000 m), identified rice landraces with different names that differed in phenotype and were adapted to the extreme high-altitude environment. Jumli Marshi was the most common traditional rice variety, accounting for 85% of samples collected. The genetic diversity of these landraces was assessed by agro-morphological variability and microsatellite marker polymorphism. Forty-two qualitative and quantitative traits and 39 microsatellite (simple sequence repeats, SSR) markers were assessed among accessions with 10 different names. The accessions showed low morphological diversity with an average Shannon Weaver diversity index of 0.23. Only 16 morphological traits showed significant variation among the accessions. Discriminant function analysis showed that only 36% of accessions could be clustered according to name by morphological traits. Only one SSR locus was polymorphic, distinguishing only one accession. The names used by farmers to describe the phenotypic characteristics of panicle and grains were inconsistent indicators of genetic identity. We conclude that the Jumla landrace population has a narrow genetic base. The diversity detected was sufficiently low for it to be possible that there was a single origin for all of the Jumla landraces.
Keywords: Agro-morpological diversity; Genetic diversity; High-altitude rice; Microsatellites; Nepal