Influencing of Some Factors on Regreening of “Valencia” Orange Fruits

Abstract

Many factors involved the regreening process of "Valencia" oranges under warm climate. Researchers focused on the difference between day and night temperatures in relation to the regreening process. This study paid a special attention to the branchbearing fruits whether its temperature or its nitrogen content before the regreening process till appearance of regreening. In addition, growth degree hours (GDH), which took into consideration the duration of effective temperature from sunrise to sunset considering the minimum degree as 13°C was also studied. Thus, the main objective of this study was to evaluate the role of the branch-bearing fruit temperature and nitrogen content on the regreening process during 2012 and 2013 seasons. The results proved that regreened "Valencia" fruits were growing on branches with greater nitrogen content, higher temperature and GDH. Furthermore, there were a high correlation between cumulative nitrogen content, temperature of branch-bearing fruits and GDH and the incidence of regreened "Valencia" oranges. Moreover, warm temperature throughout the season especially the period preceding harvest enhanced the uptake of nitrogen which reflected on more regreened "Valencia" oranges.

Performance of Adopted Fruit Species and Cultivars to Egyptian-Desert Agriculture and Their Major Production Problems

“…Moreover, a major loss of yield due to drastic-fruit abscission during flowering, fruit set and even prior to harvest. 6 Furthermore, regreening of Valencia oranges 7 and even the greening at the lower part of navel orange canopy due to warm temperature during the harvest season especially at night which causes higher mobility and activity of nitrogen in the orange tree. Thus, the objectives of this article were to demonstrate the problems associated with desert agriculture of fruits with special emphasize on abiotic ones and to briefly indicate to the possible causes of such problems and physiological disorders.…”