Mapping QTLs and identification of candidate genes for forage quality and biomass-related traits in pearl millet [Pennisetum glaucum (L.) R. Br.]
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Date
2023
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Punjab Agricultural University
Abstract
The present investigation was undertaken with the objectives to evaluate the genetic variability in the RIL mapping population along with the mapping of QTLs and identification of candidate genes for fodder quality and biomass related traits in pearl millet. The RIL mapping population comprised of 273 lines derived from the cross between Jakhrana S8-28-2-P4 (high biomass and low forage quality) x RIB 335/74-P1 (low biomass and high forage quality) was evaluated at two locations in Punjab viz., Ludhiana and Abohar in an alpha lattice design with two replications. Significant variability was observed for all the forage quality and biomass related traits at both the locations. Transgressive segregants were recovered for all the traits and stable lines for in vitro organic matter digestibility (RIL166, RIL54, RIL188, RIL57, RIL126) and total biomass (RIL256, RIL173, RIL133, RIL235, RIL179) were identified by modified AMMI stability analysis. The linkage map was constructed using 755 single-nucleotide polymorphisms (SNPs) markers spanning a length of 3080.44cM with the presence of SNP at 4.08 cM regular distance interval. Total 40, 42 and 25 QTLs were identified for Ludhiana, Abohar and across the locations, respectively for various fodder related traits. A genomic interval with flanking markers S6_234379851- S6_64109715 was found to be associated with IVOMD, CP and ME at Ludhiana, Abohar and across the locations.Major QTLs were mapped for these traitsshowing phenotypic variance ranged from 10-34%. For total biomass, major QTLs were detected on LG 1, 2, 3 and 4 and with a phenotypic variance ranged from 14-40%. The expression studies revealed the nine key candidate genes viz., BHLH 148, Resistance to phytophthora, Laccase 15, cytochrome P450, PLIM2c, GRF11, NEDD AXR1, NAC 92 and TF 089 based on differential expression between the parents in leaf tissues at active vegetative stage and reproductive stage. These genes were identified from cross taxa analysis across different crop species. The key candidate genes identified in the present study were found to regulate the cell wall biosynthesis and had a direct influence on the quality of fodder. Therefore, QTLs and candidate genes identified from this investigation would be further useful for the development of superior pearl millet genotyped for forage quality and biomass.
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Harmanpreet Singh (2023). Mapping QTLs and identification of candidate genes for forage quality and biomass-related traits in pearl millet [Pennisetum glaucum (L.) R. Br.] (Unpublished Ph.D. Dissertation). Punjab Agricultural University, Ludhiana, Punjab, India.