Agriculture Reference
In-Depth Information
• Distribution of insect-pests and diseases and thus increased cost of
inputs;
• Elevated requirements of irrigation; and
• Higher incidence of physiological disorders of fruits.
Most of the temperate fruit crops like apple, pear, peach, almond,
cherry, plum, etc. have specific chilling requirements for breaking of
dormancy (Samish and Lavee, 1982). The insufficient chillingdue to in-
creased temperature may leads to development of one or more associated
symptoms including delayed foliation, reduced fruit set, increased button-
ing and reduced fruit quality. The dormancy symptoms may persist when
winter is neither long nor not cold adequately to break the dormancy and
such situation is referred as 'Delayed foliation' when temperate fruits do
not complete their rest period because of mild winter conditions (Black,
1952; Ruck, 1975). Hauagge and Cummins (1991) reported that in addi-
tion to chill unit's accumulation, there are important interactions among
cultivars and environmental factors that are responsible for terminating
bud dormancy. In hill regions, plants grown with a winter dormancy re-
quirement, an active growing period in summer, plant phenology is main-
ly driven by temperature. After the dormancy break the development of
plants strongly depends on air temperature. With higher temperature the
biochemical reactions are accelerated up to a threshold where enzyme sys-
tems are destroyed and cells die (Chmielewski et al., 2004). Over last 20
years, the mean temperature elevated between 1.45 °C and 2.32 °Cwhich
is adversely affecting vernalization of temperate fruit crops (Ahmed et al.,
2011). The northern hilly region of India showed a general rise in tempera-
ture by approximately 0.65 °C to 2.3 °C North-western Himalayas about
0.5 °Csince last century (Bhutiyani and Kale, 2002). A shift in area of
these crops has already been witnessed in temperate zones of India. Higher
temperature also increased demand for irrigation water, which is eventu-
ally affecting the productivity of fruit crops especially being cultivated in
rain-fed regions.
The warmer temperature during dormant season induce early flowering
in plants,which become vulnerable to spring frost. In Himachal Pradesh,
the earlier plantation was primarily focused on varieties of delicious group.
During various stages of growing season, it has been noticed that these
varieties are adversely affected with changing climatic patterns (Bhatia,
2010). Above normal temperatures during flowering season affected fruit
setting due todrying of flowers. Similarly, in fruits grown under subtropical
