Title : Morphological and molecular insights into drought tolerance in chickpea.
Abstract:
Chickpea (Cicer arietinum L.) is an economically important food legume grown in arid and semi-arid regions of the world. Chickpea is cultivated mainly in the rainfed, residual moisture, and restricted irrigation condition. Chickpea like several other legumes is highly susceptible to terminal drought stress. Multiple genes control drought tolerance. Studies elucidate the association between candidate gene and morpho-physiological traits for the screening of drought tolerance in chickpea. Several genes particularly the ASR gene, DHN and ERF family play a key role in regulating different plant stresses. Analysis revealed a significant effect of drought on relative water content, membrane stability index, plant height, and yield traits. The genotypes Pusa1103, Pusa362, and ICC4958 were found most promising genotypes for drought tolerance as they maintained the higher value of osmotic regulations and yield characters. The results were further supported by a sequence similarity approach for the dehydrin gene and ASR gene when analysed for the presence of single nucleotide polymorphisms (SNPs) and indels. Homozygous indels and single nucleotide polymorphisms were found after the sequencing in some of the selected genotypes. In addition, large-scale genomic resources including several thousand simple sequence repeats and several million single nucleotide polymorphisms, high-density diversity array technology (15360 clones) and Illumina GoldenGate assay genotyping platforms, high-density genetic maps and transcriptome assemblies have been developed. In parallel, by using linkage mapping approach, one genomic region harbouring quantitative trait loci for several drought tolerance traits has been identified in ICC 4958 and successfully introgressed in three elite Indian chickpea (Cicer arietinum L.) cultivars: Pusa 372, Pusa 362, and DCP 92-3. Of eight simple sequence repeat (SSR) markers in the QTL-hotspot region, two to three polymorphic markers were used for foreground selection with respective cross-combinations. BGM 10216, with 16% yield gain over Pusa 372, has been released as Pusa Chickpea 10216 and in 2022 Pusa JG 16 was released where the mega variety JG 16 was further improved for drought tolerance by intorgression of this QTL from ICC 4958 by the Central Sub-Committees on Crop Standards, Notification and Release of Varieties of Agricultural Crops, Ministry of Agriculture and Farmers Welfare, Government of India, for commercial cultivation in India.
