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20152
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Subject: Plant Breeding and Genetics × End date: 2015 × Start date: 2015 × Thesis Type: Ph.D ×
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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.