Genetics of heat tolerance in wheat (Triticum aestivum L. em.Thell)
KrishiKosh
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Title |
Genetics of heat tolerance in wheat (Triticum aestivum L. em.Thell)
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Creator |
Gopal Singh
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Contributor |
Sarial, A.K.
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Subject |
Crossing over, Developmental stages, Grain, Planting, Wheats, Chlorophylls, Yields, Additives, Tolerance, Genetics
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Description |
The objective of present investigation was to estimate gene effects and variances of traits related to heat tolerance, grain yield and its components and to estimate and compare heritability of traits under normal and heat stress conditions. Experiment was conducted using six generations of P1 , P 2 , F 1 , F 2 , BC 1 and BC2 derived from four crosses K 7903 x Raj 4088, K 7903 x P 11632, HD 2808 x P 11632 and HD 2808 x HUW 510, Parents HD2808, K7903 heat tolerant and Raj 4088, P11632 and HUW 510 heat susceptible. Sowing was done under timely (normal) and late (heat stress) conditions in a plot size of 2 (1x 0.23) m 2 and 4 (1 x 0.23) m 2 (for F 2 ) during rabi season, 2013-14. The data were recorded for days to heading, days to anthesis, days to physiological maturity, biological yield / plant (g), grain yield/plant (g), grain weight /spike (g), 1000 grain weight (g), grain filling duration, chlorophyll content, chlorophyll fluorescence and heat susceptibility index (HSI). The results of ANOVA revealed that mean sum of squares due to crosses and generations were significantly different for all the characters studied except chlorophyll fluorescence stage-2 in both the test environments. Analysis of variance for crosses revealed that characters viz., days to heading, days to anthesis, days to maturity, chlorophyll content stage-2, plant height and grain weight per spike were highly significant under both the test environments whereas, effective tillers per plant and 1000 grain weight were significant in late sown condition only. Mean squares due to generations showed that characters viz., days to heading, plant height, effective tillers per plant, 1000 grain weight and heat susceptibility index were highly significant for both the test conditions however, days to anthesis and chlorophyll content stage-1 were significant in timely sown condition and grain weight per spike is highly significant in late sown condition. This indicated that sufficient amount of genetic variability existed in the material. Therefore, further analysis of data was done for computation of generation mean analysis proposed by Hayman (1958). Scaling tests were used to test the adequacy for additive-dominance model. Adequacy of model was observed for traits like chlorophyll fluorescence, chlorophyll content, and 1000-grain weight under both timely and late sown conditions while effective tiller per plant under timely sown and grain filling duration and grain weight per spike under late sown condition. Heat susceptibility index, the parameter of heat tolerance fitted into additive-dominant model. All the remaining traits exhibited the partial adequacy or epistasis under both the conditions. Where A-D model prevailed selection through pedigree method was suggested for improvement while bi-parental mating & recurrent selection where epistasis existed. The estimate of genetic parameters revealed that characters viz; chlorophyll content and grain yield per plant had high to moderate GCV and PCV coupled with high to moderate heritability. While days to heading, days to anthesis, days to maturity and grain filling duration exhibited low GCV and PCV along with high to moderate heritability. |
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Date |
2016-10-22T13:44:28Z
2016-10-22T13:44:28Z 2015 |
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Type |
Thesis
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Identifier |
http://krishikosh.egranth.ac.in/handle/1/81395
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Language |
en
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Format |
application/pdf
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Publisher |
CCSHAU
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