Verma, S.S.Harish, S.2017-06-032017-06-032015http://krishikosh.egranth.ac.in/handle/1/5810014236The present investigation “Varietal identification and seed vigour assessment of cotton (Gossypium spp.)” was comprised of 22 cotton varieties were studied for characterization based on morphological, chemical, biochemical and molecular markers. On the basis of morphological characters, results revealed that maximum variation was observed among the morphological characters studied for hypocotyl pigmentation, leaf colour, leaf hairiness, leaf appearance, leaf nectaries, leaf petiole pigmentation, leaf shape, plant stem hairiness, plant stem pigmentation, plant height (cm), bract type, time to 50% flowering, flower petal colour, flower petal spot, flower stigma, anther filament colouration, flower pollen colour, boll bearing habit, boll colour, boll shape (longitudinal section), boll surface, boll prominence of tip, weight of seed cotton/boll (g), seed fuzz, seed index (g), ginning % and fibre colour proved to be useful and stable diagnostic characters which could classify the varieties based on the phenotype traits. Chemical tests such as phenol, ferrous sulphate, peroxidase, potassium hydroxide and sodium hydroxide test were used to categorize different cotton varieties. Phenol and ferrous sulphate test did not show any variation among the varieties studied. Based on the colour of the peroxidase solution, the varieties were grouped as colourless and light red colour. Based on the colour of the potassium hydroxide test, the varieties were grouped as light yellow, yellow, light red, red and dark red colour and the cotton varieties were grouped as light red, red and dark red colour to sodium hydroxide test. Seedling response to gibberellic acid and 2,4-D soak test was found useful in differentiation of cotton varieties. Among the varieties, H-1300 observed maximum responsive (75.36 % coleoptile length increase over control) to GA3 test and H-1226 observed less responsive (23.37 % coleoptile length decrease over control) to 2, 4-D test. The varieties were also subjected to sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) of total soluble seed proteins. The results revealed that SDS-PAGE of seed proteins resolve total of 22 bands which were present in different position with different intensity and varieties were classified based on presence or absence of protein bands. The Gossypium hirsutum varieties were identified with the presence of band No.5 where as, Gossypium arboreum varieties were identified by the presence of band No.15 and the band number No.7, 14, 17, 18, 21 and 22 were present typically in all the cotton varieties. Furthermore, the SSR markers were able to reveal genetic variation within the species. Out of the 40 microsatellite markers, 12 markers produced a total of 32 polymorphic bands. The similarity coefficient obtained in SSR analysis ranged from 0.51 to 0.93 among the varieties and the dendrogram revealed two distinct clusters, first consisting of 16 varieties belonging to G. hirsutum and second with 6 varieties belonging to G. arboreum species, respectively. The similarity coefficient between the two species was 0.52. All the 22 varieties were subjected to various viability and vigour tests and the observations were recorded on seed weight, seed germination, seedling length, seedling dry weight, seedling vigour index-I, seedling vigour index- II, accelerated ageing test, tetrazolium test, seedling establishment, pH exudate test, electrical conductivity, field emergence index and mean germination time. The variety CISA-614 recorded maximum germination (85.67 %) and minimum electrical conductivity (0.336) whereas, MCU-12 recorded maximum seedling dry weight (529.00 mg), seedling vigour index-I (2495) and seedling vigour index-II (43544). The variety AKA-7 recorded maximum field emergence index (15.55) and minimum mean germination time (2.86 days).The correlation study among field and laboratory parameters revealed that standard germination was found significantly and positively correlated with accelerating ageing, tetrazolium test, pH exudate test, and vigour index-I. The electrical conductivity test was found to be negatively correlated with all the parameters.ensowing, cotton, developmental stages, genetics, proteins, planting, germinability, electrophoresis, diseases, land resourcesThesis