Diversity of <I>BADH2</I> Alleles and Microsatellite Molecules in Highland Fragrant Rice Landraces

Abstract

Fragrance is one of the most highly valued grain quality traits in rice. The fragrant rice is fetching very high price in the world market and the consumers demand is increasing over the world. Highland rice landraces has unique characteristics, containing high level of genetic diversity and some populations are fragrant rice. Therefore, the purposes of this study were to evaluate the genetic diversity and fragrant allelic variation of highland fragrant rice landraces in northern Thailand. Genetic diversity were assessed by using 12 microsatellite loci. Sensory test for aroma and headspace - gas chromatography (HS-GC) for 2-acetyl-1-pyrroline (2AP) in grain were evaluated. Re-sequencing at exon 7 of BADH2 was performed. The result showed that Buer Ner Moo contained low level of genetic diversity illustrated by heterozygosity (h = 0.012) and average gene diversity (H_S=0.015) in spite of high level of genetic differentiation (F_ST = 0.941). Probably, it is the consequence from farmer’s selection and preferences, as well as the genetic drift from the genetic bottleneck which was the consequence of farmers’ seed conserving for next season and adaptation to the specific local environment. There was BADH2 allelic variation found among the nine Buer Ner Moo populations, while BNM4 had the highest 2AP concentration (2.96 ppm) and illustrated the badh2-E7 deletion on BADH2 gene similar to KDML105 and PTT1, the popular fragrant rice in Thailand. The present results suggested that “Buer Ner Moo” rice landraces could be potentially introduced as genetic resources for fragrant rice breeding program by pure-line selection method or improved variety. The genetic analysis of rice landraces could also be used as a decision-making tool in the selection for conservation strategies.