Browsing by Author "Rajesh Kumar Dogra"
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ThesisItem Open Access GENETIC ANALYSIS OF YIELD AND CONTRIBUTING TRAITS IN STRAWBERRY (Fragaria × ananassa Duch.)(UHF Nauni, 2024-06-11) AKANKSHA SHARMA; Rajesh Kumar DograThe present investigation entitled “Genetic analysis of yield and contributing traits in strawberry (Fragaria ×ananassa Duch.)” was carried out at the Experimental Farm, Department of Fruit Science, Dr YS Parmar University of Horticulture and Forestry, Nauni, Solan, Himachal Pradesh during 2021-2023. The experimental material was comprised of F1 population of forty crosses, developed by crossing ten lines and four testers according to Line × Tester mating design. All the parents and their hybrids were planted in a Randomized Complete Block Design for their comparative evaluation. The observations were recorded on plant height, plant spread, number of leaves, leaf area, number of runners per plant, days to runner formation after planting, flower size, petal size, number of stamens, days to flowering after planting, duration of flowering, fruit length, fruit breadth, number of sepals, number of achenes per fruit, days to maturity from flowering, number of fruits per plant, average berry weight, total yield, fruit firmness, total soluble solids, titratable acidity, total sugars, reducing sugars, non-reducing sugars, anthocyanin content and ascorbic acid. The analysis of variance indicated highly significant differences among the genotypes for all the traits studied. Experimental results revealed that three lines viz., Nabila, Douglas and Royal Round and two testers viz., Camarosa and Sweet Charlie were found superior on the basis of their general combining ability studies. Four cross combinations viz., Nabila × Sweet Charlie, Nabila × Chandler, Royal Round × Camarosa and Meeherancher × Sweet Charlie were found best on the basis of mean performance, specific combining ability and heterosis studies. The components due to dominance (2 D) were higher in magnitude than additive (2 A) for all the traits under study except plant height, duration of flowering, average berry weight, total yield, total soluble solids and anthocyanin content indicated that the role of non-additive gene action was predominant. Hence, these parents and cross combinations can be used in further crop improvement programmes in strawberry.ThesisItem Open Access GENETIC IMPROVEMENT IN POMEGRANATE (Punica granatum) THROUGH INDUCED MUTAGENESIS(UHF Nauni, 2024-02-04) MUNMUN JOSHI; Rajesh Kumar DograThe contemporary study entitled “Genetic improvement in pomegranate (Punica granatum) through induced mutagenesis” was carried out during 2021-2022 at Department of Fruit Science, Dr YS Parmar University of Horticulture & Forestry, Nauni, Solan. The three cultivars viz., Kandhari Kabuli, Bhagwa and Daru were treated with physical mutagen (gamma rays) at doses of 0, 6, 9, 12, 15, 18, 21, 24 kR with the objective of inducing variability. The observations were recorded at different intervals of time after sowing in the polyhouse and after transplanting in the field conditions (20, 30 and 40 days after sowing and 70 days after transplanting, subsequently). The germination percentage, survival percentage and LD50 doses were calculated for all the three cultivars. Mutant seedlings from different concentrations of gamma rays were evaluated for morphological, biochemical and molecular characteristics. The morphological changes were observed both under polyhouse and field conditions. The LD50 dose for cvs. Kandhari Kabuli, Bhagwa and Daru were 15.26 kR, 15.08 kR, and 13.74 kR, correspondingly. Morphological characterization was done on the basis of the UPOV descriptor for the traits; plant: growth habit, plant: intensity of grey colour of main branches, shoot length (cm), young shoot: predominant number of leaves per node, leaf blade: length (cm), leaf blade: width (cm), leaf blade: ratio length/width, Leaf blade: shape of apex excluding tip; leaf blade: intensity of green colour; petiole: length; petiole: anthocyanin colouration. The disease severity was also screened for bacterial blight under field conditions, where, cv. Daru recorded the minimum disease severity percentage (6.57%) corresponding to control, followed by cv. Bhagwa (9.03%) and cv. Kandhari Kabuli (22.97%) at 9 kR. The molecular characterization was employed using 26 SSR markers to check the variability within the mutagenized seedlings with the Polymorphic Information Content (PIC), the effective multiple ratio (EMR) and the marker index (MI) aligned from 0.08 to 0.58; 0.00 to 0.17 and 0.00 to 0.06, sequentially. From the present study gamma rays induced variability for morphological traits will serve as a potential breeding material for future use.ThesisItem Open Access IN VIVO MUTAGENESIS IN APPLE (Malus × domestica Borkh.)(UHF Nauni, 2024-06-13) SARITA; Rajesh Kumar DograThe present investigation entitled “in vivo mutagenesis in apple (Malus × domestica Borkh.)” was carried out at the Experimental Farm, Department of Fruit Science, Dr YS Parmar University of Horticulture and Forestry, Nauni, Solan, Himachal Pradesh during 2021-2023. The experimental material was comprised of scion budsticks irradiated with different doses of gamma rays of two apple varieties namely Scarlet Spur II and Early Red One. The scion budsticks of both the varieties were irradiated with gamma rays (2.0 kR, 3.5 kR, 5.0 kR and 6.5 kR) and grafted onto M9 rootstock for raising M1V1 generation in the year 2022. The desired variants selected from M1V1 were grafted further onto M9 rootstock to raise M1V2 generation in the year 2023. The saplings of M1V1 generation not exhibiting any morphological variation were subjected to re-irradiation with the same respective doses as given in the previous year for raising M2V1 generation in the year 2023. The probit analysis for gamma rays indicated that the LD50 value based on survival per cent over control was determined as 4.62 kR and 4.65 kR, respectively in M1V1 generation and 4.66 kR and 4.54 kR, respectively in M2V1 generation for Scarlet Spur II and Early Red One. The observations were recorded on survival percentage, lethality percentage, plant vigor, plant type, plant habit, sapling diameter, length of internode, shoot colour, shoot pubescence, leaf blade attitude in relation to shoot, length of leaf blade, width of leaf blade, leaf blade ratio, intensity of green colour of leaf blade, leaf blade pubescence on lower side, leaf blade incisions of margins, petiole length, number of leaves, leaf area, leaf apex shape, leaf base shape, colour of young leaf, chlorophyll content, fresh weight of leaf, dry weight of leaf, mutation frequency and mutation effectiveness. The molecular analysis of the identified variants was carried out using CBDP and SCoT markers. Experimental results revealed that single dose irradiation of gamma rays has significantly influenced the plant vigor, length of internode, shoot colour, leaf dimensions, number of leaves, leaf area, petiole length, chlorophyll content, fresh weight and dry weight of leaves and mutation frequency. The repeated irradiation of gamma rays has also significantly affected all these characteristics. On the basis of DUS guidelines, 27 potential variants were identified in Scarlet Spur II and Early Red One varieties from M1V1, M1V2 and M2V1 generation and molecular analysis of these identified variants revealed that eight variants were genetically different from control plants.