HS. Generally, genotypes with HSI 0.5 are highly heat tolerant, HSI value lies in
between 0.5 and 1.0 then genotype is moderately tolerant, if HSI > 1.00 then the
genotype is susceptible.
3.4
Approaches to Mitigate Heat Stress
Growth and development stages of the plants were adversely affected by HS
depending upon the extent, stress duration, and the growth stage (Ruelland and
Zachowski 2010). Development of heat-tolerant line through screening in germplasm line and identification of genes/quantitative trait loci (QTL) involved in heat
tolerance mechanism seems to be the most appropriate strategies against HS (Asseng
et al. 2011; Chapman et al. 2012; Feng et al. 2014; Akter and Rafiqul Islam 2017)
(Fig. 3.3).
3.4.1 Screening and Breeding for Heat Tolerance
In breeding program the progress of stress tolerance actually depends upon the
availability of the good genetic stock, screening methods and selection criteria rely
Breeding approaches
Backcross
breeding
Pedigree
breeding
Conventional breeding
Development of heat
tolerant line
Exploration of genetic resources
Germplasm,
breeding lines
Land races, crops
wild relatives
Growing plants at
optimum temperature
Heat stress at different
stages of plant
Screening for trait
associated with heat
stress
Tolerance indices
correlate with yield
Molecular breeding/
Transgenic approach
Identification
of QTL
Marker assisted
selection
Transcription
factors
Heat shock
proteins
Fig. 3.3 A schematic diagram showed identification of crop tolerance to heat stress and the use of
conventional and molecular breeding strategies under heat stress environment
3 Plant Morphological, Physiological Traits Associated with Adaptation Against. . .
65
between 0.5 and 1.0 then genotype is moderately tolerant, if HSI > 1.00 then the
genotype is susceptible.
3.4
Approaches to Mitigate Heat Stress
Growth and development stages of the plants were adversely affected by HS
depending upon the extent, stress duration, and the growth stage (Ruelland and
Zachowski 2010). Development of heat-tolerant line through screening in germplasm line and identification of genes/quantitative trait loci (QTL) involved in heat
tolerance mechanism seems to be the most appropriate strategies against HS (Asseng
et al. 2011; Chapman et al. 2012; Feng et al. 2014; Akter and Rafiqul Islam 2017)
(Fig. 3.3).
3.4.1 Screening and Breeding for Heat Tolerance
In breeding program the progress of stress tolerance actually depends upon the
availability of the good genetic stock, screening methods and selection criteria rely
Breeding approaches
Backcross
breeding
Pedigree
breeding
Conventional breeding
Development of heat
tolerant line
Exploration of genetic resources
Germplasm,
breeding lines
Land races, crops
wild relatives
Growing plants at
optimum temperature
Heat stress at different
stages of plant
Screening for trait
associated with heat
stress
Tolerance indices
correlate with yield
Molecular breeding/
Transgenic approach
Identification
of QTL
Marker assisted
selection
Transcription
factors
Heat shock
proteins
Fig. 3.3 A schematic diagram showed identification of crop tolerance to heat stress and the use of
conventional and molecular breeding strategies under heat stress environment
3 Plant Morphological, Physiological Traits Associated with Adaptation Against. . .
65