Genetic variation in root morphology and microsatellite DNA loci in uplandrice (Oryza sativa L.) from Vietnam

Drought is a major constraint to the productivity of rice in upland ecosyst ems. The rice root system plays an important role in the regulation of wate r uptake and extraction from deep soil layers. The aim of this research was to study the variation in root morphology and the genetic diversity in upl and rice accessions. Thirty-three upland rice accessions originated from Vi etnam along with 13 selected upland rice lines from several other countries were used in this study. Variation in root morphology was observed in most of the investigated root traits such as maximum root length, total root dr y weight, deep root to shoot ratio, and total root to shoot ratio. Most of the traits showed significant correlation and appeared interrelated. Geneti c diversity among upland rice accessions was studied with microsatellite ma rkers. Forty-one alleles were detected with 14 rice microsatellite primer p airs among all the rice accessions. Two dendrograms have been created based on 35 microsatellite alleles and 10 morphological traits data for 38 acces sions and compared. These results provided useful information for the selec tion of suitable cross combinations for mapping quantitative trait loci (QT Ls) related to drought resistance in upland rice.