Genetic diversity of Phytophthora colocasiae isolates in India based on AFLP analysis.
Phytophthora colocasiae that causes taro leaf blight is one of the most devastating diseases of taro which is widely distributed in India. Inter and intra-specific genetic diversity among P. colocasiae isolates collected from same field was assessed using amplified fragment length polymorphism (AFLP) marker. Seven primer pairs produced 431 markers, of which 428 (99.2 %) were polymorphic. Considerable genetic variability was displayed by the isolates. The average value of the number of observed alleles, the number of effective alleles, mean Nei's genetic diversity, and Shannon's information index were 1.993, 1.385, 0.261, and 0.420, respectively. Analysis of molecular variance (AMOVA) showed that the majority (85 %) of the diversity were present within populations of P. colocasiae. Dendrogram based on AFLP molecular data using the unweighted pair group method with arithmetic mean (UPGMA) classified the P. colocasiae isolates into two major clusters irrespective of their geographical origin. Clustering was further supported by principle coordinate analysis. Cophenetic correlation coefficient between dendrogram and original similarity matrix was significant (r = 0.816). The results of this study displayed a high level of genetic variation among the isolates irrespective of the geographical origin. The possible mechanisms and implications of this genetic variation are discussed.
Division of Crop Protection, Central Tuber Crops Research Institute, Thiruvananthapuram, 695017, Kerala, India.
Vishnu Sukumari
VS
Nath
Division of Crop Protection, Central Tuber Crops Research Institute, Thiruvananthapuram, 695017, Kerala, India.
Muthukrishnan
M
Senthil
Division of Crop Protection, Central Tuber Crops Research Institute, Thiruvananthapuram, 695017, Kerala, India. hegdev64@gmail.com.
Vinayaka Mahabaleswar
VM
Hegde
Division of Crop Protection, Central Tuber Crops Research Institute, Thiruvananthapuram, 695017, Kerala, India.
Muthulekshmi Lajapathy
ML
Jeeva
Regional Centre of CTCRI, Dumduma HBC P.O, Bhubaneswar, 751 019, Orissa, India.
Raj Shekhar
RS
Misra
Division of Crop Protection, Central Tuber Crops Research Institute, Thiruvananthapuram, 695017, Kerala, India.
Syamala Swayamvaran
SS
Veena
Division of Crop Protection, Central Tuber Crops Research Institute, Thiruvananthapuram, 695017, Kerala, India.
Mithun
M
Raj
AFLP; Disease management; Genetic diversity; Phytophthora colocasiae; Spatial structure