Phylogenetic Origin of Waxy Rice Cultivars in Laos Based on Recent Observations for "Glutinous Rice Zone" and dCAPS Marker of Waxy Gene

Abstract

As for the origin of Asian cultivated rice (Oryza sativa L.), many questions and problems still remained unknown. The origin of waxy (glutinous) rice is one of these questions. For more than 30 years after Watabe's pioneer work, we have no information about "Glutinous Rice Znne" at which rice cultivars grown are waxy (glutinous) one, because the political situation of the zone had been unstable until 1990s. For the purpose to investigate the genetic diversity among waxy rice cultivars in Glutinous Rice Zone and estimate origin of waxy rice, scientific trips in Laos from 1991 to 1999 and evaluation for genetic features of waxy rice cultivars were carried out. Judging from results of the intensive observations in'95 and'96, traditional cultivars have been replaced to improved ones due to promotion of the Government. It was considered that the social, economical and environmental situations during this 30 years altered rice cultivation in this area. In whole Laos, we found that these waxy cultivars possess high phenotypic diversity such as frequency of glabrous phenotype, but show monomorphism in waxy locus. It was concluded that the waxy mutation ofcultivars in Laos had originated ftomjaponicalines, independently apparent indica-j aponica differentiation.