Anusree R Nair
Palynological approach to screen coconut genotypes for high temperature tolerance - Vellanikara Academy of Climate Change Education and Research 2017 - 143p
BSc-MSc (Integrated)
Climate change is expected to rise the global atmospheric temperature at a rate
of 0.2°C per decade. Temperature is one of the most important factors which drives
the growth and development of the crops. Reproductive phase of the crop is more
sensitive to high temperature than vegetative phase. In that pollen germination and
pollen tube length are known to be more critical thereby effecting fruit set and yield.
In this study coconut genotypes (12 numbers) were screened using the in-vitro pollen
germination technique at 10 to 50 °C at an interval of 2.5 °C and the tolerance of the
selected genotypes was confirmed invivo pollination during two extreme conditions of
winter and summer. Maximum pollen germination (54.3%) and pollen tube length
(554.5μm) was observed at 25 °C and either increase or decrease in temperature
decreased the germination. Temperatures above 40 °C and below 15 °C germination
became nil in most of the genotypes. The mean cardinal temperatures (Tmin, Topt, and
Tmax) averaged over genotypes, were 12.8 °C, 26.53 °C and 43 °C for pollen
germination and 12.7 °C, 27.53 °C and 42.96°C for pollen tube growth.Talls WCT,
LCT, FMST, dwarfs COD,GBGD and hybrids showed better adaptability to high
temperature. Dwarf variety MYD on the other hand was highly sensitive. If dwarf
variety COD had high germination at low temperature another dwarf GBGD showed
high germination under high temperature suggesting differential response amongst
genotypes. As we had hypothesized nut set was better during winter and above 30 °C
it was reduced under field condition. Nut set was low with invivo pollination by the
pollens from temperature sensitive variety CGD compared to the pollens used from
tolerant varity COD and WCT. Biochemical constituents like sugar and amino acids
and enzyme activity were found to be affected under high or low temperature. From
the study it is clear that the genotypes screened invitro for pollen germination can be
used in breeding programs to develop new genotypes that can withstand high
temperature conditions both in the present climate as well as in future warmer climate.
Climate Change Education and Research
551.6 / ANU/PA
Palynological approach to screen coconut genotypes for high temperature tolerance - Vellanikara Academy of Climate Change Education and Research 2017 - 143p
BSc-MSc (Integrated)
Climate change is expected to rise the global atmospheric temperature at a rate
of 0.2°C per decade. Temperature is one of the most important factors which drives
the growth and development of the crops. Reproductive phase of the crop is more
sensitive to high temperature than vegetative phase. In that pollen germination and
pollen tube length are known to be more critical thereby effecting fruit set and yield.
In this study coconut genotypes (12 numbers) were screened using the in-vitro pollen
germination technique at 10 to 50 °C at an interval of 2.5 °C and the tolerance of the
selected genotypes was confirmed invivo pollination during two extreme conditions of
winter and summer. Maximum pollen germination (54.3%) and pollen tube length
(554.5μm) was observed at 25 °C and either increase or decrease in temperature
decreased the germination. Temperatures above 40 °C and below 15 °C germination
became nil in most of the genotypes. The mean cardinal temperatures (Tmin, Topt, and
Tmax) averaged over genotypes, were 12.8 °C, 26.53 °C and 43 °C for pollen
germination and 12.7 °C, 27.53 °C and 42.96°C for pollen tube growth.Talls WCT,
LCT, FMST, dwarfs COD,GBGD and hybrids showed better adaptability to high
temperature. Dwarf variety MYD on the other hand was highly sensitive. If dwarf
variety COD had high germination at low temperature another dwarf GBGD showed
high germination under high temperature suggesting differential response amongst
genotypes. As we had hypothesized nut set was better during winter and above 30 °C
it was reduced under field condition. Nut set was low with invivo pollination by the
pollens from temperature sensitive variety CGD compared to the pollens used from
tolerant varity COD and WCT. Biochemical constituents like sugar and amino acids
and enzyme activity were found to be affected under high or low temperature. From
the study it is clear that the genotypes screened invitro for pollen germination can be
used in breeding programs to develop new genotypes that can withstand high
temperature conditions both in the present climate as well as in future warmer climate.
Climate Change Education and Research
551.6 / ANU/PA