02697nam a22001937a 4500999001900000082001800019100001900037245007600056260007900132300000900211502002500220520200700245650001802252650002402270700002302294856005602317942001202373952011802385  c160017d160017  a660.6bAKS/GE  aAkshara George  aGenetic diversity analysis of phytophthora colocasiae using SSR markers  aVellayanibDepartment of Plant Biotechnology, College of Agriculturec2017  a91p.  aBSc-MSc (Integrated)3 aThe main objective of this study was to analyze the genetic variation in Phytophthora colocasiae populations using SSR markers. This knowledge can be further exploited for the development of a good breeding strategy and utilization of plant resistance mechanisms for the effective disease management.
Morphological characterization of 37 P. colocasiae from all over the country and ten isolates collected from ICAR- CTCRI taro fields at fine spatial scale were performed on 6 different media. Based on the colony appearance in PDA medium, they were classified in to 8 different morphotypes. Genomic DNA extraction using modified Cooke and Duncan (1997) method yielded good quality DNA. The annealing temperatures of the 10 SSR primers (Schena et al., 2008) were calculated through gradient PCR. The primers showed 100% polymorphism and the number of bands ranged from 2 to 9. All the 10 SSR loci were found to be significantly deviated from HWE (P<0.001). The genetic diversity of each population was calculated by grouping the 47 isolates in to five populations based on their geographical locations. Nei’s gene diversity and Shannon’s information index were found to be 0 for the fine spatial scale isolates. Using the molecular scoring data, Hierarchical clustering was done and the 47 isolates were divided into two clusters in which the 2nd cluster contain maximum number of isolates. 
While performing morphological, pathological and molecular characterization of P. colocasiae isolates collected from different geographical locations of India, isolates from Odisha with a characteristic cottony morphology on PDA medium showed comparatively higher degree of virulence in the pathogenicity test. Moreover, these isolates can withstand temperature above 300C. The results of genetic diversity analysis indicate that isolates from Odisha were found to be highly diverged from other isolates. The isolates collected at fine spatial scale exhibited negligible genetic diversity with each other.

  aBiotechnology  aPlant Biotechnology  aJeeva, M L (Guide)  uhttp://krishikosh.egranth.ac.in/handle/1/5810143455  2ddccTH  001040718REFaKAUCLVbKAUCLVcTHESESd2018-04-12l0o660.6 AKS/GEp174179r2018-04-12 00:00:00w2018-04-12yTH