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20151
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Subject: Plant Breeding and Genetics × Author: Bhatia, Dharminder × Start date: 1968 × Type: Thesis ×
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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.