Agriculture Reference
In-Depth Information
from humid tropical to desert (Levy and Syvertsen, 1981). Few attempts
in the past, have been made to characterize climate under which citrus is
grown world over. Based on mean annual temperature and consequently
the diurnal changes, Reuther (1973) divided climate of world citrus into
three distinct thermal environments, namely, subtropical zone with low
diurnal variation varying between 4.7°C and 10.8°C in cooler and hotter
months, respectively covering Ocho island in Hiroshima representing hu-
mid climate, with well distributed rainfall; tropical zone characterized by
absence of seasonal change in temperature represented by Colombia with
mean maximum temperature of 32.8C in the coolest month and 34.6°C
in the hottest month; and subtropical zone with moderate diurnal variation
represented by San Joaquin valley of California having semiarid climate
with diurnal variation up to 12°C and 22°C in coolest and hottest month,
respectively.
While, according to Yelenosky (1977), climatically five citrus growing
regions of the world are delineated as: moist marine areas, such as south-
ern Japan, the black sea coast, Adriatic sea coast of Yugoslavia, parts of
Turkey, and New Zealand; subtropical, Mediterranean climate is typified
Spain, Israel, Italy, Turkey, parts of Australia, Lebanon, Greece, and the
coastal areas of California; subtropical, arid areas such as the U.S. des-
ert regions of southern California, Arizona and possibly the Rio Grande
valley of Texas; subtropical, moist areas include Florida (USA) parts of
China, India, South Africa, Brazil, and Argentina; and tropical, moist ar-
eas such as Hawaii, parts of Mexico, Central America, and others include
those where temperature lower than 18.3°C rarely occur, and rainfall is
usually heavy.
Of late, analysis on climate requirement undertaken by Jackson and
Looney (1999) revealed that ideal growth of citrus cultivars such as sweet
orange takes place between 13 and 40°C. While, lemons are more toler-
ant to cool summer temperatures than sweet orange, and do not grow well
under tropical climate. Grapefruits prefer tropical and warm tropical cli-
mate. However, not many cultivar specific climatic norms are available.
Earlier Pehrson (1976) presented than annual maturity ratios (TSS:acid) of
navel oranges for 22 years and the mean monthly temperatures for years
in which maturity advanced or delayed, each average over five years. Ad-
vanced maturity is associated during the year of high spring temperature
(number of degree, days over 23°C).
