Previously, it has been recognized that citrus growing regions have large difference not only in growth and yield of tree but also in physico-chemical characteristics of fruits. Soil, climatic conditions and cultural conditions determine the adaptability of a specific variety for commercial growing in a particular citrus growing region. Climate is the crucial component of the climate-soil-culture complex, which contribute in causing variation in growth, yield and fruit qualities among commercial citrus producing areas. Internal and external quality of citrus fruit quality fluctuate sharply with climate (Goldschmidt, 1997; Reuther, 1988). Among all the elements of climate, temperature found to be the main climatic factor that influence fruit quality (Goldschmidt, 1997; Reuther, 1973).
Temperature: Temperature is the most important environmental factor affecting the citrus fruit quality. The rates of fruit growth and maturation depends upon the temperature prevails during the growing season. In the tropical climate with year round warm temperatures, fruit growth and maturation is more rapid than in the tropical climate with a year round cool temperature (Reuther, 1980). The prevalent temperature and the rate of acid degradation in the juice especially during the latter half of the fruit growth and maturation period, have a constant relationship between them. Under climate of high temperature and high humidity, developing fruits are tender and rapidly senescing fruit which