Genetic diversity of Myanmar rice and their implementation on management methods

Abstract

Myanmar has diverse agronomic landscape and potentially preserves high level of genetic resources for important crop species. However, little study on rice landrace diversity in Myanmar has been done. Genetic and phenotypic variation to characterize rice genetic resource in Myanmar was analyzed using molecular markers as well as common garden experiments. Two populations of rice landraces, a seedbank population maintained by seed-propagation in a genebank for several generations and an “onfarm” population collected from agricultural lands were used. A functional (cytochrome P450 related PBA) and neutral (SSR) markers were used in this study. Phenotypic characteristics of representative agronomic traits in rice, such as culm length, panicle length, number of tillers and days to heading, were measured in both populations. Multivariate analysis suggested that the seed-bank and on-farm population had different genetic bases with both functional and neutral markers. There was no significant relationship between the functional and neutral markers based on Mantel test. In addition, PCA analyses of agronomic traits showed that a variation in the seed-bank population had narrower genetic bases than the on-farm population. Genetic bias caused by ‘unconscious selection’ during the genebank management processes may have occurred in the landraces. The importance of the conservation on on-farm landraces of Oryza sativa and its wild relatives was proposed in order to ensure the genetic resources for further breeding and conserve biological diversity.

Key words: Oryza sativa, rice, landrace, on-farm, diversity, conservation.