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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)
 
Creator Gopal Singh
 
Contributor Sarial, A.K.
 
Subject Crossing over, Developmental stages, Grain, Planting, Wheats, Chlorophylls, Yields, Additives, Tolerance, Genetics
 
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.
 
Date 2016-10-22T13:44:28Z
2016-10-22T13:44:28Z
2015
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/81395
 
Language en
 
Format application/pdf
 
Publisher CCSHAU