Articles
CHILLING ACCUMULATION DURING THREE YEARS IN A SUBTROPICAL CLIMATE PROVINCE (NANGARHAR) OF AFGHANISTAN WITH REFERENCE TO TEMPERATE FRUIT TREES GROWING
Article number
1059_12
Pages
107 – 114
Language
English
Abstract
Afghanistan is located in the Central Asia and has several different agro-ecological zones due to long distance from Northern and Southern latitude (about 1,250 km) and the particular orography.
The cultivation of the main temperate fruit trees is placed in the centre of the country where the cold temperatures during the winters are enough to overcome the bud endo-dormancy.
However, in some provinces of the East and South which is located at low altitude, winters are warm and some subtropical species (guava, citrus) grow along with temperate ones (apricot, almond and peach). Up to now in Afghanistan, particularly in the warm areas, no information is available both for the chilling accumulation and the chilling requirement of the local cultivars.
During three years (2007-2010) the hourly daily temperature was recorded, collected and evaluated using modified Richardson formula (PCU), and Dynamic model (CP). The chilling accumulation started in the third week of November and finished in the second week of February.
The accumulation of both data showed variability during the tested years.
The blossom of local temperate fruit trees occurred in February but varied among plant species, such as almond bloom during the first week, peach bloom during the second week and apricot bloom during the fourth week.
The benefits from the evaluation of chilling accumulation in the area are: selecting cultivars to match the chill received on local orchard sites, determining if and when to apply rest breaking chemicals, assessing if cultural management practices to reduce chill requirement are appropriate, forecasting crop performance, and interpreting year to year differences in cultivar performance.
The cultivation of the main temperate fruit trees is placed in the centre of the country where the cold temperatures during the winters are enough to overcome the bud endo-dormancy.
However, in some provinces of the East and South which is located at low altitude, winters are warm and some subtropical species (guava, citrus) grow along with temperate ones (apricot, almond and peach). Up to now in Afghanistan, particularly in the warm areas, no information is available both for the chilling accumulation and the chilling requirement of the local cultivars.
During three years (2007-2010) the hourly daily temperature was recorded, collected and evaluated using modified Richardson formula (PCU), and Dynamic model (CP). The chilling accumulation started in the third week of November and finished in the second week of February.
The accumulation of both data showed variability during the tested years.
The blossom of local temperate fruit trees occurred in February but varied among plant species, such as almond bloom during the first week, peach bloom during the second week and apricot bloom during the fourth week.
The benefits from the evaluation of chilling accumulation in the area are: selecting cultivars to match the chill received on local orchard sites, determining if and when to apply rest breaking chemicals, assessing if cultural management practices to reduce chill requirement are appropriate, forecasting crop performance, and interpreting year to year differences in cultivar performance.
Authors
G.A. Finetto
Keywords
chilling unit (CU), chill portions (CP), growth degree hour (GDH), chilling requirement (CR)
Online Articles (32)