Molecular characterization and stability study in Indian mustard (Brassica juncea L.) genotypes under early and terminal heat stress
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Date
2019
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DRPCAU, Pusa
Abstract
Present study entitled “Molecular characterization and stability study in Indian mustard (Brassica juncea L.) genotypes under early and terminal heat stress” conducted under early-timely—late-sown environments during Rabi 2017-18 and 2018-19 at research farm of TCA Dholi. The twenty genotypes belonging to various geographic locations and diverse pedigree reflected their genetic worth for thirty five morpho-physio-biochemical traits exhibiting sufficient variability. PCV higher than GCV revealed varying environmental influence. High h2 bs and GAM for LMSI, TSS, PA & PC in early and terminal stress conditions showed preponderance of additive gene action. Positive and significant association of VPD, DFFO, D50%F & DPM while, negative with PAPD expressed their phonological inter-relationship and more usefulness of VPD & PAPD for terminal heat stress condition. SYP positively with HI, EL, CC & PH (and also between EL & CC); while, negative with H.T.E. (early & terminal heat stress); OC, SPB & PC (early-sown) whereas, SI & H.S.I. (late-sown). SI & H.S.I. decrease with increased H.T.E. and subsequently, increased SYP can be utilized. HI with high positive direct effect and association was major yield predictor (early & late-sown) alongwith BYP (early) and EL, RWC & CC (terminal) heat stresses. On Tocher‘s, Canonical (vector) and K-mean clustering, Rajendra Sufalam and Urvashi (oligo-genotypic) alongwith RAURD-14-18, BPR-541-4, DRMR4001, DRMR-15-9, RGN-368, RGN-13, PRE-2013-19 and KMR (E)16-1 were divergent genotypes and also reflected desirable per se for various morpho-physio-biochemical traits. Nine crosses between divergent parents suggested 5 crosses involving DRMR-15-9, RAURD-14-18, BPR-541-
4, DRMR4001 & RGN-368 with Urvashi; and 4 crosses involving RGN-13, RGN-368, PRE-2013-19 & KMR (E) 16-1 with Rajendra Sufalam. PA & H.T.E. contributed maximum towards total divergence under both stress environments. Molecular diversity analyses also reflected PRE-2013-19, KMR (E)16-1 & RAURD-14-18 as divergent as well as genotypes with unique alleles; whereas, DRMR-15-9, Rajendra Sufalam and RGN-368 as genotypes with unique alleles. Thus, reflecting their overall usefulness as divergent genotypes. NI2A09, showed best polymorphic bands, highest (0.636) PIC values and four alleles per locus and can be effectively utilized for studying diversity of Indian mustard genotypes. Studied genotypes reflected variability in all six environments except for CT & RGR. Rajendra Sufalam offered stability under poor environment and found most suitable genotype for terminal heat stress-late-sown & timely-sown conditions. Also it was only stable stable (rich environment) genotype for oil content overall six environments as well as diverse stable parent with superior per se for many traits including SYP. RGN-13 with average and rich environment stability in early-timely and late-timely-sown conditions whereas, RAURD-14-11 and BPR-541-4 (rich environment stability) suitable for farmers for both early and late-sown with timely-sown agroecologies of Bihar. Suggested Indian mustard plant type for heat stress condition, the emphasis is required towards seedlings and early growth stages before flowering (SDW-VPD-DFFO), PAPD, DPM, high: LPMA, PBP, SPMA, SPB, SL, TSW, RWC & CC including SI, H.S.I. and H.T.E.