Genetic diversity of rice (oryza sativa l.) Landraces conserved at the national genebank as revealed by simple sequence repeat (ssr) dna markers

EXTENDED ABSTRACT 

There is high degree of rice diversity in Tanzania. Increased human population pressure and activities has caused the population of wild rice to disappear at alarming rate. NPGRC collected over 125 accessions of rice landraces and 7 wild relatives for conservation and sustainable utilization in improvement programs, but no morphological or genetic diversity study that have been done to support any future collections. An investigation was conducted to determine the extent of genetic diversity and relationship among 79 rice (Oryza sativa L.) landraces and its wild relative conserved at the NPGRC in Tanzania. Fourteen quantitative morphological characters analysed indicated that rice germplasm conserved at the NPGRC has considerable diversity range. The yield related characters such as grain length (r = 0.360), flag leaf width (r = 0.511), and one hundred seed weight (r = 0.319) showed significant and positive association with grain yield per accession. Principal components analysis indicated that the first four components with Eigen values >1 accounted for 63.99% of the morphological variability among rice accessions studied. The cluster analysis grouped accessions into four groups, one group for wild rice accession and the rest three groups for mixed accessions. Five SSR primers were used to determine genetic diversity, 11 polymorphic alleles were revealed, alleles per locus ranged from 2 to 3. Primer RM 333 revealed large number of alleles. Jaccard’s similarity coefficient revealed that most of the accessions evaluated were genetically similar, except few are distinct. Study also highlighted use of large number of SSR markers (>5) for efficient characterization of the rice accessions conserved at the genebank and those used in this study. This work is expected to be published in African Journal of Biotechnology (AJB); Academic Journal