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Author: Chohan, Prashant Kumar × End date: 2018 × Start date: 2010 × Type: Thesis × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Studies on epidemiology and molecular diversity of cotton leaf curl virus (CLCuV) in cotton (Gossypium hirsutum L.)
    (CCSHAU, 2016) Chohan, Prashant Kumar; Mehta, Nareshcc
    Present investigation comprised two cultivars HS-6 and RCH 134 BG-II susceptible to CLCuV used for study on epidemiology, effect of date of sowing and spacing on the incidence of cotton leaf curl disease (CLCuD). Biochemical studies included phenol, sugar (total and reducing), tannin, protein, gossypol, chlorophyll-a & b, peroxidase and pholyphenol oxidase analysis using standard biochemical methods. Four cotton cultivars HS-6 & RCH 134 BG-II (susceptible) and H 1236 & Bunty (resistant) were used in the study. For molecular study, cotton leaves showing CLCuD symptoms were collected from different cotton growing locations of Haryana (Sirsa, Fatehabad, Hisar, Bhiwani and Jind), Punjab (Abohar, Bathinda and Fazilka) and Rajasthan (Hanumangarh and Shriganganagar). Results exhibited that disease was appeared early in season during 2013 whereas late in 2014, however, fluctuation in white fly population during 2014 did not affect CLCuD progress. Negative correlation of CLCuD was observed with T-max and T-min, whereas, RH (morning) showed positive correlation. In early sown crop, the disease appeared at later stages of crop as compared to timely and late sown crops. Overall yield of early sown crop was highest whereas, yield in late sown crop was significantly reduced in two year of study. The effect of spacing on incidence of CLCuD was not significant. Biochemical studies revealed that phenol content was high in resistant plants whereas, low in diseased plants. Tannin content was high in resistant plants as compared to diseased plants. However, gossypol and sugar (total and reducing sugar) content changes did not show any relation with CLCuD infection in plants. Protein content was increased with the age of plant. Chlorophyll (a & b) content was higher in diseased plants as compared to healthy/resistant plants. Peroxidase and Polyphenol oxidase activity was higher in healthy (0 grade) and resistant plants in comparison to the diseased plants. Molecular study revealed that primers used in molecular level study showed differences in DNA amplification. Among the 68 samples, 36 showed DNA presence in all three primers, 4 showed in Primer-1, 7 in Primer-2, 3 in primer-3 and 4 samples did not show amplification in any of the primers. Five samples showed amplification with primer-1 & 2, 5 in primer-2 & 3 and 4 samples showed presence in primer-1 & 3 only. Monomorphic results observed did not show variability in amplified DNA of various isolates. However, the presence or absence of band with particular isolate indicated complex system of analysis of host-virus-vector relation.