Citrus (Citrus spp.)
Citrus is one of the major fruit crops after mango, banana, and apple. More than
100 varieties are grown commercially around the world, so it has great economic
return in international trade. Citrus is widely grown in different climatic zones from
tropical to subtropical to semiarid zones (Abobatta 2019). Temperature is a critical
factor for successful citrus production; it is grown at an optimum range of temperatures between 16 and 27
C. High temperature reduces fruit growth by decreasing
net CO 2 assimilation and also increases fruit drop. Adverse effects of high temperature and moisture stress can delay fruit maturity, flatten peel colour, and increase
fruit splitting and creasing; low temperature (frosts and freezing) damages the fruits
or, if it persists for a long time, may kill the plant. In navel oranges the content of
TSS (Total Soluble Solids) was affected by increasing acidity. Among other important climatic factors, the rainfall in September and October has great effect on fruit
quality in terms of TSS, and less rainfall increases the TSS content in fruits (Mitra
2018). It changes climate affect also in fruit enlargement, peel puffing, and reduction
of acid concentration in Satsuma mandarins (Sugiura 2019). Elevated temperature
also increases the water requirement in tropical regions and reduced flowering in
subtropical regions. Warming also favours scale and mite attacks. Increasing temperature above 30
C promotes vegetative flush instead of flowering flush (Nath
et al. 2019). High temperature increases fruit cracking and sunburn (Figs. 4.3 and
4.4) in ‘Washington’ sweet orange and mandarin hybrids such as ‘Murcott’ and
‘Nova’ (Gracia-Luis et al. 1994).
Practical of Horticulture
1. Identification of horticultural crops
2. Different propagation techniques of horticultural crops
3. Given them to make Herbarium sheet of horticultural crops
Practical of Forestry
1. Identification of forest trees
4. Given them to make Herbarium sheet of Forest trees
2. Planning of making home garden/multi-stories Farming
Ongoing - How to take measurement of falling trees
Fig. 4.2 Assessment of future climate risk for major banana-producing countries (by 2050). This
categorization was carried out by combining changes in predicted yield under the RCP 8.5 climate
change scenario and the effect of cultivation efficiency (technology trend) on past yields. Countries
classified as ‘at risk’ are those where yields are predicted to decline because of climate change and
that have shown a negative technology trend on past yields. ‘Adaptable’ countries could see future
climate-driven yield declines but mitigation could be possible given past positive technology trends.
Countries at an ‘advantage’ are those that are predicted to experience climate-driven increases in
yield by 2050 regardless of past technology trends. Countries are grouped by region. Brazil, China,
and India are considered to be stand-alone regions (Varma and Bebber 2019)
86
T. Sarkar et al.
Citrus is one of the major fruit crops after mango, banana, and apple. More than
100 varieties are grown commercially around the world, so it has great economic
return in international trade. Citrus is widely grown in different climatic zones from
tropical to subtropical to semiarid zones (Abobatta 2019). Temperature is a critical
factor for successful citrus production; it is grown at an optimum range of temperatures between 16 and 27
C. High temperature reduces fruit growth by decreasing
net CO 2 assimilation and also increases fruit drop. Adverse effects of high temperature and moisture stress can delay fruit maturity, flatten peel colour, and increase
fruit splitting and creasing; low temperature (frosts and freezing) damages the fruits
or, if it persists for a long time, may kill the plant. In navel oranges the content of
TSS (Total Soluble Solids) was affected by increasing acidity. Among other important climatic factors, the rainfall in September and October has great effect on fruit
quality in terms of TSS, and less rainfall increases the TSS content in fruits (Mitra
2018). It changes climate affect also in fruit enlargement, peel puffing, and reduction
of acid concentration in Satsuma mandarins (Sugiura 2019). Elevated temperature
also increases the water requirement in tropical regions and reduced flowering in
subtropical regions. Warming also favours scale and mite attacks. Increasing temperature above 30
C promotes vegetative flush instead of flowering flush (Nath
et al. 2019). High temperature increases fruit cracking and sunburn (Figs. 4.3 and
4.4) in ‘Washington’ sweet orange and mandarin hybrids such as ‘Murcott’ and
‘Nova’ (Gracia-Luis et al. 1994).
Practical of Horticulture
1. Identification of horticultural crops
2. Different propagation techniques of horticultural crops
3. Given them to make Herbarium sheet of horticultural crops
Practical of Forestry
1. Identification of forest trees
4. Given them to make Herbarium sheet of Forest trees
2. Planning of making home garden/multi-stories Farming
Ongoing - How to take measurement of falling trees
Fig. 4.2 Assessment of future climate risk for major banana-producing countries (by 2050). This
categorization was carried out by combining changes in predicted yield under the RCP 8.5 climate
change scenario and the effect of cultivation efficiency (technology trend) on past yields. Countries
classified as ‘at risk’ are those where yields are predicted to decline because of climate change and
that have shown a negative technology trend on past yields. ‘Adaptable’ countries could see future
climate-driven yield declines but mitigation could be possible given past positive technology trends.
Countries at an ‘advantage’ are those that are predicted to experience climate-driven increases in
yield by 2050 regardless of past technology trends. Countries are grouped by region. Brazil, China,
and India are considered to be stand-alone regions (Varma and Bebber 2019)
86
T. Sarkar et al.