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M. Sc. Dissertations

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2015 - 20162
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Author: Sonika × Start date: 2011 × Type: Thesis ×
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    ThesisItemOpen Access
    Genetical, biochemical and molecular basis of cotton leaf curl virus disease in gossypium hirsutum L.
    (CCSHAU, 2016) Sonika; Sangwan, R.S.
    The inheritance of cotton leaf curl virus disease indicated the complementary type of gene interaction (9:7) which indicated that this trait was digenically controlled. Generation mean analysis revealed significant differences for some traits where the A, B, C and D individual scales were also significant for some characters indicated thereby the presence of non-allelic interactions. Additivedominance model was found fit for days to flower in crosses (I, II and III), boll number in crosses (II, III and IV), boll weight in crosses (I, II and IV), GOT in all the four crosses, seed index in cross (IV), lint index in all the four crosses and seed cotton yield in crosses (I, III and IV). Dominance component was significant for most of the characters. Duplicate type of interaction was apparent for days to flower (cross IV) and plant height in crosses (I, II and IV). Among biochemical parameters, sugar content was significantly higher in susceptible parents than resistant parents. Phenol, tannin, gossypol content and enzymatic activities of peroxidase and polyphenoloxidases were significantly higher in resistant parents as compared to susceptible parents. Oil content did not show any particular trend. The correlation matrix among different biochemical parameters revealed that cotton leaf curl virus disease (CLCuD) grading (0-6) at 60 DAS, showed positive significant correlation with sugar content while other biochemical parameters viz. phenol, gossypol, tannin, crude protein and enzymes peroxidase (PO) and polyphenoloxidase (PPO) showed significant negative correlation. CLCuD grading did not show any correlation with oil content. The same trend was observed in all of the four crosses at 60 and 90 days after sowing (DAS) except in sugar, phenol, polyphenoloxidase (PPO) and protein (90 DAS). Twenty eight ISSR primers were used to study molecular variation among parental genotypes and their F1s. A total of 175 alleles were amplified unambiguously by 28 ISSR primers, of which 127 alleles were polymorphic (72.57 per cent). Polymorphic information content (PIC) value was found in the range of 0.495 to 0.907. The ISSR primer UBC 834 was found to have maximum PIC value (0.907) which indicated that this primer is more informative and can be further used to identify resistant genotypes from the germplasm or breeding material. The cluster analysis led to the distribution of parents and their F1s in to different groups at the similarity coefficient value of 0.54-0.85. Cluster A, included parent HS 6, cluster B bifurcated further into different sub-clusters indicated that parents GCH 3 and H 1353 and their F1s were present on the upper side of the dendrogram and parents HS 6 and RST 9 on the lower side of the dendrogram. Genetic similarity by ISSR analysis showed that parental genotypes GCH 3 and HS 6 were quite distinct from each other.
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    ThesisItemOpen Access
    Response of tetranychus urticae koch (Acari: Tetranychidae) to plant age and fertilizers in brinjal
    (CCSHAU, 2015) Sonika; Gulati, Rachna
    Studies on the seasonal incidence of Tetranychus urticae on brinjal revealed that mite attacked from September to November, 2014 with peak in the last week of September, 2014 (2.78 to 6.18 mites/sq cm leaf) in all the fertilizer treatments. Peak in T. urticae population was observed during last week of September, 2014 (5.85 mites/sq cm leaf) under screen house conditions. Leaf wise, maximum population developed on grown up leaves (2.56 mites/ sq cm leaf) followed by 2.47 and 1.70 mites/ sq cm leaf on tender and older leaves, respectively ; former two were statistically comparable with each other. Among abiotic factors, T. urticae population showed significant positive correlation with maximum temperature (r =0.87), minimum temperature (r =0.77), wind velocity (r=0.79) and sunshine hours (r =0.87) under field conditions. A significant negative correlation was, however, recorded with morning relative humidity (r = -0.77). Investigations were carried out to access the damage caused by T. urticae in brinjal. Among the parameters recorded, number of chlorotic patches on brinjal leaves, reducing sugars and phenols increased in proportion to mite population; former showed significant increase. Additionally, fruit number, length, width and weight, nitrogen, potassium and phosphorus decreased significantly in response to T. urticae population as compared to control during study period. There was no effect of mite infestation on total sugar contents and non reducing sugar of brinjal leaves Under field conditions, highest reduction in T. urticae population was achieved with farmyard manure (15 t/ha), followed by neem cake (3 q/ha), farmyard manure (20 t/ha), poultry manure (3 t/ha), neem cake (2q/ha), poultry manure (2.5t/ha), NPK (100:50:25) and vermicompost (2.5 t/ha), showing 55.56, 53.59, 52.59, 51.96, 48.37, 41.50, 18.30 and 11.11 percent reduction over control, respectively.