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20165
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Subject: Plant Breeding and Genetics × Start date: 2016 × Type: Thesis × Thesis Type: M.Sc ×
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    Allelic variation for meiosis related genes in Brassica juncea and its diploid progenitors
    (Punjab Agricultural University, Ludhiana, 2016) Snehdeep Kaur; Banga, S.S.
    Patterns of allelic differentiation were investigated for meiotic genes in natural and resynthesized B. juncea allotetraploids as well as their progenitors. Pollen fertility was wide-ranging, with B. juncea showing the maximum variation. A representative set of 96 lines was then genotyped with 70 STS markers. Fifty five polymorphic markers amplified 137 alleles. Within population differences (76%) accounted for maximum variation, followed by variation among species (19%). Population structure analysis largely reflected the ploidy boundaries. Diploids were grouped together, but B. juncea formed two major subgroups. Linkage disequilibrium (LD) deviated significantly between species and subpopulations as well. Large LD block with MMD1 was observed for B. juncea. For diploids, MRE11 and TES spanned major LD blocks. Markers based on two candidate genes, SCC3 and BRCA2b showed significant association with pooled pollen fertility. These explained 11-14 % of the trait variation. For B. juncea, only MS5b provided evidence of directional selection using softwares Arlequin and LOSITAN. Tajima’s D values were negatively significant for RAD51C, ZYP1a and ZYP1b for A homolog, indicating balancing selection. B homolog of SWI1 showed evidence of positive selection. Hierarchical clustering analysis based on gene expression indicated diverse meiotic machinery in B. juncea as compared to progenitor species. MEI1, ZYP1a, ZYP1b were transgressively over expressed in B. juncea. In contrast; SPO11-1, DMC1, BRCA2a, MSH2, MSH4, MMD1 and TES were distinctly down regulated in B. juncea. There seemed to be a distinct balance between co-upregulation or –down regulation of identified meiotic genes in both natural and freshly resynthesized allopolyploids, suggesting that changes in gene expression regulation may occur in the early aftermath of genome merger.
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    ThesisItemOpen Access
    Characterization of an intra-hirsutum RIL population of RS 2013 × PUSA 56-4 cross
    (Punjab Agricultural University, Ludhiana, 2016) Khushpreet Kaur; Rathore, Pankaj
    The current investigation was carried out to study the genetic variability among recombinant inbred lines derived from the cross between American cotton lines RS 2013 and PUSA 56-4. The experimental plant material consisted of 193 recombinant inbred lines, parents, and standard check. The field evaluation of plant material was undertaken in a simple lattice design (14 x 14) with two replications at Ludhiana and Faridkot for two kharif seasons of 2014 and 2015. Observations were recorded on various yield and its component traits and fibre quality parameters. Standard check (LH 2108) significantly outperformed the RILs for seed cotton yield, lint yield, ginning outturn, and bolls per plant. Line 37 recorded the highest boll weight (4.2 g) and lint index (4.8). The range for some important traits recorded to be 44.5-119.4 (seed cotton yield plant-1), 14.6-40.8 (lint yield plant-1), 2.5-4.2 (boll weight), 28.3-35.5 % (ginning outturn), 1.6 - 3.4 (monopods plant-1), 22.7 - 28.6 mm (2.5% span length), 21.6 - 28.9 g/tex (fibre strength), and 3.2 - 4.6 (micronaire). A subset of the lines along with parents, standard check and TM-1 was subjected to molecular genetic analysis employing cotton specific microsatellite markers. The 40 lines were grouped into three main clusters. Both the parents were grouped together in the same cluster.
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    ThesisItemOpen Access
    Induction of genetic variability through gamma rays in pigeonpea (cajanus cajan (l.) Millspaugh)
    (Punjab Agricultural University, Ludhiana, 2016) Gaur, Amit Kumar; Inderjit Singh
    The present investigation was conducted to induce genetic variability in yield contributing traits in local variety AL 201 and to isolate desirable mutants for important traits which can be used as such as new varieties or as parents in hybridization programme for developing superior varieties. Two doses of gamma radiation i.e. 30 kR and 40 kR were used to induce mutations and the experiments were conducted in the experimental farm area of Pulses Section, Deptt. of Plant Breeding and Genetics, Punjab Agricultural University, Ludhiana, during kharif season of 2014 and 2015. The effect of gamma rays treatment on the per cent seed germination was studied in M1 generation under both laboratory as well as field conditions and results indicated that the gamma rays had an inhibitory effect on the per cent seed germination of pigeonpea and these negative effects was more severe with increasing dose of the mutagen. In M2 generation, mutant plants were selected and were divided into different groups for desirable traits like earliness, dwarfness, profuse branching and more yield per plant for both the doses i.e 30 kR and 40 kR. For these traits mean of selected plants was significantly different from mean of control plants. Among all the groups, group V (30kR) was considered as the best as it contained early maturing plants, dwarf plants, plants with more fruiting branches and high yield than the parent AL 201. A set of 20 already identified M3 derived M4 mutant lines were evaluated for various morphological traits and protein content. Analysis of variance revealed that mean squares were significant for all the traits. Mutant genotype AL 2138 was identified as the shortest and earliest line having more yield than the parent variety AL 201. The other mutant lines AL 2127, AL 2128, were found promising for pods per plant, 100-seed weight, fruiting branches per plant and seed yield. The highest value of phenotypic coefficient of variation (PCV) was obtained for seed yield per plot whereas, the highest genotypic coefficient of variation (GCV) was recorded for fruiting branches. High heritability estimates were reported for days to maturity and days to flowering. The highest genetic advance as per cent of mean was recorded for number of fruiting branches per plant. Seed yield per plot recorded positive and significantly high correlation with fruiting branches, pods per plants, 100-seed weight, plant height, days to flowering and days to maturity.
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    ThesisItemRestricted
    Physiological and Molecular Characterization of Cold Tolerant Sugarcane Germplasm
    (Punjab Agricultural University, Ludhiana, 2016) Brar, Amrinder Singh; Sandhu, Surinder K
    In the state of Punjab, the reasons for low productivity of sugarcane are primarily the adverse agro-climatic conditions prevailing in the region. Sugarcane is a cold sensitive plant and its active growth period in Punjab is confined to six to seven months from April to October. Research on cold tolerance is of vital significance as chilling stress affect the quality of mid-maturing cane varieties in sugarcane crop and sprouting of ratoon crop. Conscious efforts were made to select cold tolerant genotypes from huge germplasm assemblage of 1200 genotypes. The selected set of 24 tolerant genotypes was extensively assessed for physio-biochemical parameters in reference to 24 sensitive genotypes as check under natural cold conditions. The significant differences among tolerant and sensitive genotypes for proline, chlorophyll, total soluble sugars, free amino acids, relative water content and carotenoids before and after cold stress elucidated the role of these parameters in imparting cold hardiness. Based on agronomic profiling, cryo-protectant physio-biochemical traits and cane quality, genotypes CoJ 88, ISH 260, ISH 313, ISH 260, F 110/09, F 228/09, CoS 03261 and CoS 03222 were selected as cold tolerant genotypes having high economic potential and suggested for their utilization in breeding for cold tolerance. Visual screening of genotypes, although needed validation can be authentically used for selection of cold tolerance. Expressed Sequence Tags (ESTs), sequences from public domain, reported to be upregulated in response to cold stress were blasted with sorghum genome and primers were designed using corresponding genomic region encoding proteins of Heat Shock Proteins (HSP) and No Apical Dominance (NAM). Molecular markers HSP Sorghum3 and NAM Soghum2 exhibited allelic size polymorphism between tolerant and sensitive genotypes. The two sequence tagged microsattelite markers (STMS) viz., NKS 45 and NKS 46 were found to be associated with high and low sugar content, respectively. These identified markers could be of high utility to screen a large breeding population for high sucrose content at initial growth stage in long duration sugarcane crop. The study could serve a strong foundation to initiate breeding for cold tolerance in sugarcane.
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    ThesisItemOpen Access
    MAPPING OF FRUIT LENGTH RELATED QTLs IN INTERSPECIFIC CROSS OF Capsicum annuum L. × Capsicum galapagoense HUNZ.
    (Punjab Agricultural University, Ludhiana, 2016) Arjun, K.; Dhaliwal, M. S.
    Chilli (Capsicum annuum L.) is one of the major commercial spice and vegetable crop of India that has attracted breeder’s attention for the improvement of various economic traits. Fruit length that contributes directly to the total yield is quantitatively inherited and makes phenotypic selection tedious with low genetic gains. To facilitate marker assisted selection (MAS), quantitative trait loci (QTL) analysis was performed to identify fruit length related QTLs in an interspecific cross of Capsicum. The mapping population consisting of 210 F2plantswas derived from the cross between Capsicum annuum L. “FL 201” bearing long fruits and Capsicum galapagoense Hunz. ‘TC 07245” bearing very small fruits. The genetic map with 24 linked markers contained 3 linkage groups (LGs) covering a total distance of 399.0 cM with an average marker interval of 16.6 cM. On the basis of the interspecific map, two fruit length related QTLs designated as paufl2.1 and paufl2.2 were identified on LG 2.The QTL paufl2.1 was found to be the major QTL explaining 13.38 per cent of the phenotypic variation with likelihood score of 5.53. The minor QTLpaufl2.2explained 8.4 per cent of the phenotypic variation with likelihood score of 5.26. Both the QTLs showed positive additive genetic inheritance suggesting that these genomic regions play significant role in enhancing pepper fruit length. The identified QTLs might serve as potential target regions for identifying candidate genes through fine mapping.