• Ashutosh

      Articles written in Journal of Genetics

    • A duplicated coxI gene is associated with cytoplasmic male sterility in an alloplasmic Brassica juncea line derived from somatic hybridization with Diplotaxis catholica

      Aruna Pathania Rajesh Kumar V. Dinesh Kumar Ashutosh K. K. Dwivedi P. B. Kirti P. Prakash V. L. Chopra S. R. Bhat

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      A cytoplasmic male sterile (CMS) line of Brassica juncea was derived by repeated backcrossing of the somatic hybrid (Diplotaxis catholica + B. juncea) to B. juncea. The new CMS line is comparable to euplasmic lines for almost all characters, except for flowers which bear slender, needle-like anthers with aborted pollen. Detailed Southern analysis revealed two copies of coxI gene in the CMS line. One copy, coxI-1 is similar to the coxI gene of B. juncea, whereas the second copy, coxI-2 is present in a novel rearranged region. Northern analysis with eight mitochondrial gene probes showed altered transcript pattern only for the coxI gene. Two transcripts of 2.0 and 2.4 kb, respectively, were detected in the CMS line. The novel 2.4 kb transcript was present in floral bud tissue but absent in the leaf tissue. In plants where male sterility broke down under high temperature during the later part of the growing season, the 2.4 kb coxI transcript was absent, which suggested its association with the CMS. The two coxI genes from the CMS line showed two amino acid changes in the coding region. The novel coxI gene showed unique repeats in the 5′ region suggesting recombination of mitochondrial genomes of the two species. The possible role of the duplicated coxI gene in causing male sterility is discussed.

    • Assessment of genetic diversity in Indian rice germplasm (Oryza sativa L.): use of random versus trait-linked microsatellite markers

      Sheel Yadav Ashutosh Singh M. R. Singh Nitika Goel K. K. Vinod T. Mohapatra A. K. Singh

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      Assessment of genetic diversity in a crop germplasm is a vital part of plant breeding. DNA markers such as microsatellite or simple sequence repeat markers have been widely used to estimate the genetic diversity in rice. The present study was carried out to decipher the pattern of genetic diversity in terms of both phenotypic and genotypic variability, and to assess the efficiency of random vis-à-vis QTL linked/gene based simple sequence repeat markers in diversity estimation. A set of 88 rice accessions that included landraces, farmer’s varieties and popular Basmati lines were evaluated for agronomic traits and molecular diversity. The random set of SSR markers included 50 diversity panel markers developed under IRRI’s Generation Challenge Programme (GCP) and the trait-linked/gene based markers comprised of 50 SSR markers reportedly linked to yield and related components. For agronomic traits, significant variability was observed, ranging between the maximum for grains/panicle and the minimum for panicle length. The molecular diversity based grouping indicated that varieties from a common centre were genetically similar, with few exceptions. The trait-linked markers gave an average genetic dissimilarity of 0.45 as against that of 0.37 by random markers, along with an average polymorphic information constant value of 0.48 and 0.41 respectively. The correlation between the kinship matrix generated by trait-linked markers and the phenotype based distance matrix (0.29) was higher than that of random markers (0.19). This establishes the robustness of trait-linked markers over random markers in estimating genetic diversity of rice germplasm.

    • Identification of drought stress-responsive genes in rice (Oryza sativa) by meta-analysis of microarray data


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      Meta-analysis provides a systematic access to the previously studied microarray datasets that can recognize several commonsignatures of stresses. Three different datasets of abiotic stresses on rice were used for meta-analysis. These microarray datasets were normalized to regulate data for technical variation, as opposed to biological differences between the samples. A t-test was performed to recognize the differentially-expressed genes (DEGs) between stressed and normal samples. Gene ontology enrichment analysis revealed the functional distribution of DEGs in different stressed conditions. Further analysis was carried out using software RICE NET DB and divided into three different categories: biological process (homoiothermy and protein amino acid phosphorylation), cellular component (nucleus and membrane), and molecular function (zinc ion binding ad DNA binding). The study revealed that 5686 genes were constantly expressed differentially in Oryza sativa (2089 upregulated and 3597 downregulated). The lowest P value (P = 0.003756) among upregulated DEGs was observed for naringenin, 2-oxoglutrate 3-dioxygenase protein. The lowest P value (P = 0.002866816) among the downregulated DEGs was also recorded for retrotransposon protein. The network constructed from 48 genes revealed 10 hub genes that are connected with topological genes. These hub genes are stress responsive genes that may also be regarded as the marker genes for drought stress response. Our study reported a new set of hub genes (reference genes) that have potentially significant role in development of stress tolerant rice.

    • Evaluation of disease resistant and high yielding faba bean germplasm in India


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      Faba bean (Vicia faba L.) is one of the earliest domesticated food legumes after chickpea and pea in the world. It is been produced in many countries including China, Ethiopia, Egypt, northern Europe, the Mediterranean region, central Asia, East Asia, Latin America and as a minor crop in India. The crop is affected by many diseases and alternaria leaf blight (Alternaria spp.) is one of the seriousthreat to faba bean production. Twenty-five lines of faba bean were selected from three international nurseries and were evaluated at ICARDA-FLRP-Amlaha during 2016–2017 and 2017–2018, to identify resistant lines against alternaria blight disease. A wide range of variation to disease reaction was observed among faba bean genotypes. One faba bean line (S2011-134) found tolerant, six genotypes (S2011-116, FLIP15-139, FLIP15-156, FLIP15-159, FLIP15-164-S2 and FLIP15-169) were found moderately tolerant and 16 genotypes were found susceptible to alternaria blight. The faba bean genotypes showed resistance to the disease scoring (0–9) with high yield as compared to the checks, Giza and Gwalior local. The identified sources of resistance can be utilized in faba bean breeding programmes for the development of disease tolerant cultivars with high yield.

    • Inheritance and biochemical basis of yellowing of apical leaves: a unique trait in chickpea (Cicer arietinum L.)


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      A unique trait, i.e. yellowing of apical/young leaves in response to low temperature and high relative humidity was identified in a chickpea genotype, ICCX110069. To determine inheritance pattern of this trait, ICCX110069 was crossed to four other genotypes, GL14050, GL14049, GL14059 and SAGL152117, that exhibited normal green apical leaves under similar environmental conditions. The F1, F2, F3, BC1F1 and BC1F2 generations were generated. A ratio of 13 normal green leaf: three yellow leaf was found to be the best fit, indicated digenic gene action with suppressor effect of normal green leaf over the expression of yellowing of apical/young leaf trait. The chlorophyll content was significantly lower, while guaiacol peroxidase activity was significantly higher in yellow leaves of ICCX110069 as compared to green leaves of the same genotype and of GL14049, indicating the competence of antioxidative defence mechanism involvedwith the expression of this trait.

    • Identification and morphological characterization of promising kabuli chickpea genotypes for short-season environment in central India


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      Chickpea (Cicer arietinum L.) is an important food legume crop grown in arid and semi-arid regions of the world. In India, kabuli chickpea is grown in central India in ~0.5 million ha, predominantly under short winter (< 110 days). Efforts are underway to select promising genotypes at the Food Legume Research Platform (FLRP), Amlaha, located in intensive kabuli chickpea growing area of India.Sixty-four kabuli chickpea lines were evaluated for agronomic traits during 2017–2018 and 2018–2019 crop seasons at FLRP following simple 8 X 8 lattice design with two replications. The analysis of variance over two years revealed significant variation exists for days to flowering, plant height, maturity period, biomass, seed size and seed yield. It was observed that with similar maturity time (106 days), FLIP09-432C produced 2273 kg/ha, which out-yielded the popular variety in central India, JGK-3 by 15%. The breeding lines, FLIP09- 436C, FLIP09-171C, FLIP09-373C and FLIP09-247C were also found promising for earliness (104–110 days), and high yielding with the good yield ability (1003–2273 kg/ha). These promising genotypes for a short duration with good yield have been selected and can be used for various chickpea breeding programmes to develop high yielding varieties in central India.

    • Consequence of cyclic pollen selection for heat tolerance on the performance of different generations in maize (Zea mays L.)


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      The reproductive stage in many crops, including maize, is very sensitive to heat stress and the genetic overlap between gametophytic and sporophytic phase gives an opportunity to select superior stress tolerant genotype at gametophytic stage. An attempt was made to evaluate the response of cyclic pollen selection in the F1 and F2 generations on the performance of F3 generation progenies for seed yield and yield contributing traits under natural heat stress conditions. In this direction three groups of F3 progenies, namely (i) pollen selection in F1 and F2 generations (GG), (ii) pollen selection only in F2 generation (CG), (iii) no pollen selection in F1 and F2 generations (CC) were screened for heat stress at Agricultural Research Station (ARS), Bheemarayanagudi. The GG progenies recorded significantly higher chlorophyll content, more number of pollen grains per anther and less pollen sterility compared to CG and CC group of progeniesunder heat stress. Further, the F4 progenies obtained through cyclic pollen selection (in F1, F2 and F3) were also tested for heat stress tolerance at seedling stage. The significant improvement for heat stress tolerance was recorded in F4 progenies derived through cyclic pollen selection as compared to control (no pollen selection for heat tolerance in any generation) F4 progenies. The results indicated that cyclic pollen selection in F1, F2 and F3 generations improved the heat stress tolerance of the progenies in the succeeding generations. To provide genetic evidence for the effect of pollen selection for heat tolerance, the control F2 (C) and selected F2 (G) populations were compared for the segregation of SSR markers. The selected F2 (G) population showed significant deviation from normal Mendelian ratio of 1:2:1 and showed skewness towards the alleles selected from male parent. The results provide strong evidence for an increase in the frequency of parental alleles in the progenies that impart heat stress tolerance.

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