MORPHOLOGICAL AND MOLECULAR CHARACTERIZATION OF BLAST RESISTANT GENOTYPES OF RICE

Abstract

Genetic divergence analysis was done for blast resistant and susceptible genotypes using 13 morphological characters. The genotypes were grouped into seven clusters according to D2 statistic and Canonical Vector analysis. Plant height, days to flowering, days to maturity, panicle length, number of spikelet/ panicle, number of filled grain/ panicle, number of unfilled grain/ panicle, 1000 filled grain weight(gm), yieldlhill(grn) were indicated as important contribution to genetic divergence in 14 rice genotypes. On the basis of cluster distances, high yielding along with highly susceptible (BRR] dhan 29) genotypes could be crossed highly resistant genotypes (BR 6017-3-3-4-1, ZHONG-YU 7) and BRR] dhan 28 and BRR] dhan 36 could be croosed with QING LIALI NO] for the development of blast resistant rice varieties. A total of 8 microsatellite and 3 minisatellite or VNTR markers were used for studying molecular variabi lity across 14 blast resistant and susceptible rice genotypes. A total of 33 alleles were detected at the loci of 8 microsatellite markers across 14 blast resistant and susceptible rice genotypes. The number of alleles per locus ranged from 2 alleles (RM ) OS) to 5 alleles (RM21, RMSO, RM531), with an average of 4.13 alleles across the 30 loci. The Polymorphism Information Con ten! (PIC) values ranged from 0.2S0 (RMIOS}'to 0.726 (RM21). PJC value revealed that RM21 was considered as the best marker for 14 rice genotypes. The two dimensional graphical view of Principal Coordinate Analysis (PCoA) for blast resisitant genotypes showed the genotypes ZhongYu7, OM1207, SIPI692033, BRRI dhan29, BRRI dhan36, QINGLlALJ 1, JR 60913-42-3-3-2-2 and NJ70507 were found placing far away from the centroid of the cluster and rest of the genotypes were placed more or less around the centroid. The genetic similarity analysis using UPGMA clustering system generated nine genetic clusters with similarity coefficient of 0.66 for the study with blast disease resistance. The pair-wise genetic dissimilarity coefficients indicated that the highest genetic distance was obtained between NJ70507 with BR36 & BR29 for blast disease. In order to develop blast resistant varieties and broaden the genetic base of rice varieties new breeding program should initiated preferably using the parents, BRRldhan29 and NJ70507 and BRRldhan36 and NJ70507 and to create genetic variability among these two modem rice varieties. Both molecular and morphological data did not show the similar results. So, use of more molecular markers might be resolved the results of morphological analysis.