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Thesis

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2014 - 20164
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Subject: Plant Breeding and Genetics × Start date: 2014 × Thesis Type: Ph.D ×
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Now showing 1 - 4 of 4
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    ThesisItemOpen Access
    Molecular marker and morphological characterization of triticale x wheat derivatives
    (PAU, 2015) Feltaous, Yousef Mohsen; Bains, N.S.
    The study is based on near homozygous derivatives from three crosses: TL 2908/2*CSS//PBW 343; TL 2908/2*CSS//DBW 17 and TL 2908/2*CSS//PBW 550 where TL 2908 is an improved, amber grained triticale variety, CSS is a bread stock carrying Ph suppressor genes in Chinese Spring background and PBW 343, DBW 17 and PBW 550 are bread wheat varieties used as recipient parents. As all the recipient wheat varieties carried 1B/1R translocation, it was expected to be present in half of the derivatives. Out of 1244 lines screened using SSR marker diagnostic of 1B/1R translocation (SCM 9), 652 turned out to be non 1B/1R. The lines negative for 1B/1R translocation were screened for presence of rye chromatin using a universal marker (Rye R3/F3). A large proportion (266 out of 552 lines, 48.2%) was positive for rye chromatin. A set of 164 derivatives positive for rye chromosome introgression were taken up for evaluation in replicated trials. Transfer of large anther size and high anther extrusion was indicated in several derivatives, which is relevant for hybrid wheat development. Sixty five derivatives showing almost complete resistance to highly virulent stripe rust race 78S84 were evaluated in a separate trial. While all the recipient bread wheat parents were highly susceptible to stripe rust and Karnal bunt, twelve derivative lines combined high level of resistance to stripe rust (mostly 0 or ts) and Karnal bunt (less than 2% infection). Another three lines were found to be highly tolerant to micronutrient deficiency. SSR marker based screening of elite derivatives revealed three lines to carry rye chromosome 5 (and three lines with rye chromosome 6. One line carried both chromosomes 5R and 6R.
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    ThesisItemOpen Access
    Molecular characterization of inter-specific backcross inbred lines of rice (Oryza sativa L.) for mapping of yield component QTL
    (PAU, 2015) Bhatia, Dharminder; Singh, Kuldeep
    We need to significantly increase the yield potential of rice for feeding estimated 9 billion populations by 2050. For increasing yield potential in rice, utilization of wild species is one among the several strategies advocated. In the present study, Backcross inbred lines (BILs) derived from O. longistaminata acc. IRGC104301 (longi-BILs), O. rufipogon acc. IRGC104433 (rufi-BILs) and O. glumaepatula acc. IRGC104387 (glumae-BILs) in the background of O. sativa ssp. indica cv. PR114 were used for mapping QTLs consistently contributing variation for yield and yield component traits. BILs were evaluated for yield and yield component traits as compared to recurrent parent PR114 as check in alpha lattice design over three seasons spanning two locations. A modified Genotyping by sequencing approach was used for genotyping. Sequence data for each population was analysed with custom designed method exactly similar for each population to identify SNPs. A total of 3322 informative SNPs of rufi-BILs and 3437 informative SNPs of glumae-BILs were used for mapping QTLs for twelve yield and yield component traits using inclusive composite interval mapping. SNPs identified in longi-BILs could not be used for mapping due to large number of missing data points. In rufi-BILs, QTL for thousand grain weight (qtgw5.1) was mapped on chromosome 5 consistent over all the three seasons and with positive additive effect contributed by O. rufipogon allele. Two QTLs for grain width (qgw5.1 and qgw5.2) were also mapped on chromosome 5 with positive and negative additive effect respectively. In glumae-BILs, three consistent QTL for thousand grain weight on chromosome 2 (qtgw2.1), 3 (qtgw3.1) and 6 (qtgw6.1) were mapped consistently for season 2 and 3. QTLs qtgw2.1 and qtgw6.1were associated with positive additive effect, while qtgw3.1 with negative additive effect contributed by O. glumaepatula allele. Two QTL for grain length (qgl7.1 & qgl7.2) with positive additive effect contributed by PR114 allele was mapped on chromosome 7 spanning overlapping position in both rufi-BILs and glumae-BILs respectively. qgl7.1 and qgl7.2 might be same QTL as contributed by same parent and spanning overlapping position. QTL for other yield and yield component traits could not be identified due to skewed segregation.Yield component QTLs identified in the present study from low yielding wild relatives of rice reveals their significance in improving yield of cultivated rice. Combining these QTLs in the background of cultivated rice will not only increase the yield, but also widen the genetic base of cultivated rice.
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    ThesisItemOpen Access
    Genetic Diversity and Association Studies for traits Related to Water Stress Tolerance in a Structured Brassica Juncea Population
    (PAU, 2014) Akhatar, Javed; Banga, S.S.
    A core subset of genetically fixed lines (48) was selected through stratified sampling to represent the allelic variations within Brassica juncea gene pool. The molecular characterization by 158 nuclear and nine chloroplast SSR markers revealed distinct germplasm patterns. There were significant interactions between chlorotype and seed/biological yields. Test genotypes were also evaluated for twenty four morpho-physiological traits over two years under normal and restricted moisture regimes for association studies. Highly significant marker-trait associations (MTA‟s) were identified by General Linear Model [GLM-PC (Principal Component)] Mixed Linear Model [MLM-PC+K (Kinship)]. MTA‟s include days to maturity, grain yield, number of secondary branches, number of seeds per pod, thousand seed weight, average root diameter and root length. Single marker, SB1822-1, localized at 17.5cM on chromosome 13 was repeatedly detected for seed size and grain yield. Marker, SB3872-3 revealed significant effect under normal moisture on seed size during the year one. Among the favorable double alleles, SB1822-1 showed positive phenotypic effect for thousand seed weight and grain yield. Of the four double alleles, cnu316-3 had maximum positive phenotypic effects on grain yield. Maturity QTLs (Quantitative Trait Loci) detected on J6 (A genome) have been repeatedly detected in past studies with diverse in B. napus. Novel QTLs were identified for photosynthetic active radiation interception (cnu031-1 and SB1728-3) and drought tolerance index (NI3-G07-1 and SB1935A-1) and canopy air temperature difference. The loci identified by us need to be verified and utilized for breeding tolerant cultivars to improve crop performance under variable moisture conditions.
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    ThesisItemRestricted
    Genetic enhancement of grain zinc content in high yielding wheat varieties
    (Punjab Agricultural University, Ludhiana, 2016) Charan Singh; Sohu, V.S.
    Two approaches for genetic enhancement of grain zinc content in high yielding wheat lines was pursued under the study. In the first approach high grain micronutrient content from Triticum monococcum and Triticum boeoticum introgressed into tetraploid (T. durum) background served as donors. The recipient parents utilized were hexaploid high yielding wheat varieties of North Western Plane Zone such as DPW621-50, HD2967 and WH1105 along with two gene pyramided version of PBW343 (carrying rust resistance genes Yr10, Yr15, Lr24, and Lr28). A total 1077 progenies (BC2F2) from different cross combinations were generated and evaluated for grain zinc content other agronomic and quality traits. Analysis of variance for augmented block design revealed that genotypes differed significantly for grain zinc concentration (ppm). A set of highly promising 271 progenies with more than 70 ppm grain zinc concentration and 25 progenies with more than 80 ppm grain zinc concentration were identified. The highest grain zinc and iron concentration was observed in progenies of gene pyramided parent PBW698 with introgression from BF22 used as tetraploid donor. The monitoring of previously mapped grain micronutrient QTL in this cross showed the markers identified at diploid level to be non polymorphic. The second approach followed in this study employed grain micronutrient enhancement via positive association of grain micronutrient and protein content with Gpc-B1 gene, originally derived from T. dicoccoides. A back cross RIL population of 94 Gpc-B1 positive lines derived from cross Glupro/3*PBW568 showing wide variation in protein and micronutrient content and several agronomic traits including plant height and thousand grain weight in a two year evaluation experiment was used in a correlation analysis. Analysis of variation and correlation studies showed that the lines which possess high grain protein content, grain zinc and iron concentration were low yielding with less number of grains per spike, bolder grains, earlier maturity and relatively more plant height. It showed that increase in grain protein content was constrained and a compromise of yield and yield components was observed. Further, yield reduction could arise in more than one ways. For instance, there could be reduction in grain per spike as observed in this study or thousand grain weight as indicated by several reports in the literature. In spite of yield-quality trade off commercially useful product-specific lines can be derived. The relatively tall and early but bold grains lines with exceptionally high protein (15-16%) and micronutrient content (70-80 ppm) in the above studied set can be shortlisted as product specific (bread making) high premium cultivar after further testing. In a second set of experiments under this approach, DPW621-50 derivatives with Gpc-B1 gene were evaluated for yield, yield components and grain zinc content. Pooled analysis of variance and correlation coefficient analysis indicated that Gpc-B1 gene was less effective in high yielding DPW621-50 background. This gene moderately enhanced grain protein content and grain zinc and iron concentration in DPW621-50 derivatives with some reduction in thousand grain weight and grain yield. It was seen that the Gpc-B1 gene must be allowed sufficient flexibility of productivity trait combinations for its protein and grain enhancement effects to be manifested.