Articles written in Journal of Genetics

    • Identification and introgression of QTLs implicated in resistance to sorghum downy mildew (Peronosclerospora sorghi (Weston and Uppal) C. G. Shaw) in maize through marker-assisted selection

      H. C. Lohithaswa K. Jyothi K. R. Sunil Kumar Puttaramanaik Shailaja Hittalmani

      More Details Abstract Fulltext PDF

      Sorghum downy mildew caused by Peronosclerospora sorghi is a major disease of maize and resistance is under the control of polygenes which necessitated identification of quantitative-trait loci (QTLs) for initiating marker-assisted introgression of resistant QTLs in elite susceptible inbred lines. In the present study, QTLs for sorghum downy mildew (SDM) resistance in maize were identified based on cosegregation with linked simple sequence repeats in 185 F2 progeny from a cross between susceptible (CM500-19) and resistant (MAI105) parents. F3 families were screened in the National Sorghum Downy Mildew Screening Nursery during 2010 and 2011. High heritability was observed for the disease reaction. The final map generated using 87 SSR markers had 10 linkage groups, spanning a length of 1210.3 cM. Although, we used only 87 SSR markers for mapping, the per cent of genome within 20 cM to the nearest marker was 88.5. Three putative QTLs for SDM resistance were located on chromosomes 3 (bin 3.01), 6 (bin 6.01) and 2 (bin 2.02) using composite interval mapping. The locus on chromosome 3 had a major effect and explained up to 12.6% of the phenotypic variation. The other two QTLs on chromosomes 6 and 2 had minor effects with phenotypic variation of 7.1 and 2%. The three QTLs appeared to have additive effects on resistance. The QTLs on chromosomes 3 and 6 were successfully used in the marker-assisted selection programme for introgression of resistance to SDM in eight susceptible maize lines.

    • Development and application of genomic resources for comparative and translational genomics in legumes through leveraging genomic sequence of Medicago truncatula


      More Details Abstract Fulltext PDF

      The expressed sequence tags (ESTs) of common bean were BLAST aligned with barred medic genome sequence and developed 1196 conserved intron spanning primers (CISPs) to facilitate genetic studies in legumes. Randomly selected 288 CISPs, representing loci on barrel medic genome, were tested on 10 selected members of legume family. On the source taxa, the highest single copy amplification success rates of 61.8% (barrel medic) and 56.2% (common bean) was obtained. The success rate of markers was 54.5% in cowpea followed by 53.5% in pigeonpea and chickpea, signifying cross taxon amplification and their potential use in comparative genomics. However, relatively low percentages of primer set amplified (40–43%) in soybean, urdbean and peanut. Further, these primers were tested on different varieties of chickpea, pigeonpea and cowpea. The PCR products were sequenced and aligned which resulted in detection of 26 SNPs and eight INDeLs in cowpea, seven SNPs and two INDeLs in chickpea and 27 SNPs and 14 INDeLs in pigeonpea. These SNPs were successfully converted in to size variation for gel-based genotyping. The CISP markers developed in this study are expected to aid in map saturation of legumes and in marker-assisted selection for accelerated crop improvement.

    • Genetic characterization of maize doubled haploid lines for Fusarium stalk rot caused by Fusarium verticillioides


      More Details Abstract Fulltext PDF

      Fusarium stalk rot disease (FSR) of maize caused by Fusarium verticillioides (Sacc.) Nirenberg is becoming an importantbiotic production constraint in many of the major maize growing areas causing substantial yield losses. Inbreds are preferred as parents inhybrid development owing to homozygous nature and high heterotic ability. Double haploid (DH) technology has emerged as a significantmilestone. A total of 339 DH lines were generated from two inbred lines, VL1043 (susceptible) and CM212 (resistant), through in vivohaploid induction method. The 339 DH lines along with parents were phenotyped for their response to the FSR at the College ofAgriculture, V. C. Farm, Mandya, India during summer, kharif and rabi seasons of the 2019–2020. Best linear unbiased predictors (BLUPs)were estimated for the FSR disease scores over three seasons. Awide range of BLUP scores of three to nine indicated the presence of highervariation for response of DH lines to FSR disease. The higher estimates of standardized range (1.31) and phenotypic coefficient of variation(19.80) also displayed higher variability. Nine lines were moderately resistant and 188 exhibited moderately susceptible reaction. Thedistribution of DH lines was positively skewed (1.34) and platykurtic (2.31) which suggested complementary epistasis and involvement oflarge number of genes in the disease expression.

    • Discovery of SNPs in important legumes through comparative genome analysis and conversion of SNPs into PCR-based markers


      More Details Abstract Fulltext PDF

      Compared to cereal crops several legumes are less characterized at the genomic level and rightly referred as orphan crops. Transfer of knowledge between model and crop legumes allows development of orthologous pan-taxon genomic tools to benefit research on resource poor taxa. Here, we developed 278 intron flanking gene-specific markers by BLAST aligning pigeonpea (Cajanus cajan (L.) Millsp.) expressed sequence tags (ESTs) with complete genome sequence of barrel medic (Medicago truncatula). A random 192 PCRprimer pairs representing loci across the haploid genome (n = 8) of barrel medic were tested on a few important members of legume family. The single copy amplification rates of 31.8% (peanut, Arachis hypogaea) to 77.6% (barrel medic) signifies the success of cross taxon primers and suggested their potential use in comparative legume genomics. Genetic diversity was assessed in 48 pigeonpea genotypes using 143 intron flanking markers which revealed 71 polymorphic markers with PIC values ranging from 0.04 to 0.45 with an average of 0.23 permarker. The PCR products of different varieties of pigeonpea, cowpea and chickpea were sequenced and aligned to find putative SNPs. Integration of these newly developed markers into genetic maps in resource poor legumes will not only aid in the map saturation but also in designing successful marker-assisted selection programmes.

  • Journal of Genetics | News

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

© 2021-2022 Indian Academy of Sciences, Bengaluru.