Chickpea (Cicer arietinum L.) is a dry season food legume largely grown on residual soil moisture after the rainy season. The crop often experiences moisture stress towards end of the crop season (terminal drought). The crop may also face heat stress at the reproductive stage if sowing is delayed. The breeding approaches for improving adaptation to these stresses include the development of varieties with early maturity and enhanced abiotic stress tolerance. Several varieties with improved drought tolerance have been developed by selecting for grain yield under moisture stress conditions. Similarly, selection for pod set in the crop subjected to heat stress during reproductive stage has helped in the development of heat-tolerant varieties.A genomic region, called QTL-hotspot, controlling several drought tolerance-related traits has been introgressed into several popular cultivars using marker-assisted backcrossing (MABC), and introgression lines giving significantly higher yield than the popular cultivars have been identified. Multiparent advanced generation intercross (MAGIC) approach has been found promising in enhancing genetic recombination and developing lines with enhanced tolerance to terminal drought and heat stresses.
K E Y W O R D SCicer arietinum, climate change, early maturity, high temperature, moisture stress, molecular breeding
Drought stress significantly affects chickpea production. The “QTL-hotspot”, a genomic region on pseudomolecule Ca4 in chickpea that harbours major-effect quantitative trait loci (QTLs) for multiple drought-adaptive traits, represents a promising target for improving chickpea drought adaptation. To investigate the mechanisms underpinning the positive effects of “QTL-hotspot” on seed yield under drought, this study introgressed the “QTL-hotspot” region from ICC 4958 genotype into five elite chickpea cultivars. The resulting introgression lines (ILs) and their parental lines were evaluated in multi-location field trials and semi-controlled experiments. The results showed that the “QTL-hotspot” region improves seed yield under water deficit by: (1) increasing seed weight, (2) reducing flowering time, (3) regulating canopy growth-related traits, and early vigour, and (4) enhancing transpiration efficiency. Whole-genome sequencing data analysis of ILs and parental lines revealed four genes underlying the “QTL-hotspot” region associated with drought adaptation. We validated diagnostic KASP markers closely linked to four genes using ILs and parental lines for deployment in chickpea breeding programs. The CaTIFY4b-H2 haplotype of a potential candidate gene CaTIFY4b was identified as the superior haplotype for 100-seed weight. The candidate genes and superior haplotypes identified in this study could serve as direct targets for genetic manipulation and selection for chickpea improvement.
The experiment was conducted to find out appropriate moisture stress mitigation technique for rabi urdbean under rainfed conditions. The different moisture stress mitigation techniques viz., 2% KCl, 6% Kaolin, soil mulch, removal and incorporation of alternative rows, 2% KCl + 0.1% Boron, 2% Urea, 0.1% Nitrophosk (19:19:19 N:P:K), 0.1% Boron were tried along with absolute control and water spray. Among the different treatments, 2% KCl + 0.1% Boron spray at flowering and pod initiation stages recorded significantly higher grain yield (724 kg/ha) than other treatments (460-555 kg/ha) except 6% Kaolin (629kg/ha). Whereas gross returns (H 37898/ha), net returns (H 29138/ha) output/input (2.66) and energy use efficiency (81.35 kg/1000 MJ) were significantly higher in the treatment 2% KCl + 0.1% Boron over others.
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