Agriculture Reference
In-Depth Information
varieties have strong tendency of alternate bearing after a few years of
commercial fruit production, which is also one of the reasons, which ac-
count for low production during the off-years. These varieties are highly
susceptible to low temperature and frost and hail injury during flowering
which also accounts for low production.
4.2.2 CLIMATIC CONSTRAINTS
Irregular bearing behavior of Starking Delicious is largely influenced by
climatic conditions. The rains and hails during flowering adversely affects
the fruit-set whereas moderate temperature of 20 °C with relatively low
rains during flowering results in good fruit-set. Low temperature during
prebloom or bloom stage can cause sub lethal injury to buds or flowers
resulting in poor fruit-set and crop load. Early flower anthesis and full
bloom were observed in good crop years. Long flowering period is also
indication of good crop prospects.
4.3 IMPACT OF CHANGING CLIMATE CONDITIONS ON
CHILLING UNITS, PHYSIOLOGICAL ATTRIBUTES AND
PRODUCTIVITY OF APPLE IN HIMACHAL HIMALYAS:
BACKWARD LINKAGE
At the University of Horticulture and Forestry Solan comparative investi-
gations have been undertaken to study the influence of winter temperatures
below 7 °C on effective chill units (ECU), growing degree hours Celsius
(GDH°C) requirements and physiological changes associated with the bud
dormancy of Starking Delicious apple under two locations viz., location
A (ideal apple growing conditions with an altitude of 2286 in amsl) and
location B (marginal apple growing conditions with an altitude of 1375 m
amsl). Using the Utah Model, the effective chill unit requirements for lo-
cation A and B were 1208 and 1130, respectively, whereas, the GDH°C re-
quirements from rest completion to full bloom for the respective locations
were 8893 and 9376. The quantitative analysis of physiological compo-
nents indicated varying pattern during the course of dormancy. The effects
of various chilling units on bud break and biochemical attributes in young
potted apple plants were studied under controlled conditions. It has been
