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Studies on molecular diversity, heterosis, combining ability and high temperature tolerance in Brassica juncea L. Czern & Coss
KrishiKosh
View Archive Info| Field | Value | |
| Title |
Studies on molecular diversity, heterosis, combining ability and high temperature tolerance in Brassica juncea L. Czern & Coss
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| Creator |
Singh, Vikrant
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| Contributor |
Ram Bhajan
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| Subject |
mustard, genotypes, plant physiology, correlation, heat stress, molecular diversity, heat tolerance
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| Description |
Thesis-PhD
The studies were carried out in two separate experiments at N.E Borlaug Crop Research Centre, PCPGR and Oilseed Quality Lab of G.B. Pant university of Agriculture & Technology, Pantnagar (Uttarakhand) during 2009-10 to 2011-12. In Experiment-I, 45 Indian mustard genotypes were studied for physiological traits and yield based stress parameters to analyze correlations among them as well as to evaluate their response to heat stress, and also to analyze molecular diversity using SSRs during 2010-11. In Experiment-II, 12 heat tolerant lines×4 heat susceptible testers (selected based on outcomes of Experiment-I) were studied for combining ability and heterosis in early sown seedling heat stress (E1), timely sown non-stress (E2), late sown terminal heat stress (E3) as well as pooled over environments (P) during 2011-12. Results showed presence of substantial variability for all traits in all environments in both the experiments. In general, PCV was higher than GCV with close correspondence between them for all traits. The GCV was higher for physiological traits while moderate to high for yield based stress parameters among 45 genotypes. Heritability in broad sense (h2 b) and genetic advance in % of mean (GA%) were high for all physiological traits as well as yield based parameters. Among physiological traits; cell membrane stability (CMS%), acquired thermal tolerance (ATT%) and % reduction in relative water content (%RRWC) were used as key trait to classify the genotypes for their response to heat stress which led to identify 13 as tolerant, 11 as moderately tolerant and 21 as susceptible genotypes. Further on the basis of % yield reduction in E1 and E3 from E2, eight out of tolerant genotypes identified earlier, were found tolerant to seedling stage heat stress and two genotypes (PRL 06-37, PRL 08-7) as tolerant to terminal stage heat stress. These physiological traits and yield based stress parameters exhibited significant desirable correlation with seed yield. Physiological traits also manifested significant desirable correlations with yield based stress parameters. Four chlorophyll content based parameters (Chl a, Chl b, Chl a/b ratio and total chlorophyll contents) and TOL among yield based parameters were not effective in discrimination of genotypes for thermotolerance due to inconsistent results. SSRs diversity analysis exhibited up to 100% allelic polymorphism, up to 0.336 PIC value and 0.167 to 1.000 Jaccard’s similarity coefficient. UPGMA ordered the pool of 45 genotypes into four clusters. Only one unique locus of ~930 bp was found in SKM 0526 with NA10-CO1a primer. Combining ability results showed σ2gca/σ2sca ratio less than unity with average degree of dominance more than unity for all traits in all environments indicating predominance of non-additive genes in the expression of all yield traits. The lines namely Urvashi in E1, PR 08-5 in E2 as well as in P, and PRL 08-6 in E3 as well as testers namely RH 0304 in E1, E2 and P, and JMWR 08-3 in E3 exhibited highest GCA for seed yield which were accompanied by high GCA in desirable direction for 4-5 component traits. The crosses namely PRL 07-3×RH 0304 in E1, PRL 07-3×JMWR 08-3 in E2, PR 06-1×RK 08-2 in E3 and EJ 20×RK 08-2 in P exhibited maximum SCA value for seed yield. For seed yield, five top ranking crosses were found entirely different for each environment which indicated that manifestation of heterosis was cross and environment specific. The most outstanding heterotic crosses for different environments were Urvashi×RH 0304 in E1, PR 08-5×JMWR 08-3 in E2, PRL 08-6×RH 0304 in E3 and P for seed yield along with high heterosis for 4-6 component traits. |
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| Date |
2016-06-15T13:56:14Z
2016-06-15T13:56:14Z 2013-05 |
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| Type |
Thesis
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| Identifier |
http://krishikosh.egranth.ac.in/handle/1/67411
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| Language |
en
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| Format |
application/pdf
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| Publisher |
G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
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