Physio-Chemical And Histological Studies On Some Navel Orange Cultivars Under Egyptian Condition

Abstract

This study was carried out during ( 2018/2019and 2019/2020) years in a private Orchard at Al Nubaria Region to
study some physio-chemical and productivity of some navel orange cultivars named: Nave-late; Lane-late and
Navelina (Citrus Sinensis L Osbek) budded on X 639 rootstock (Cleopatra mandarin X Poncirus trifoliate).The results
revealed that Lane-late orange cultivar significantly has the highest values of shoot length, shoot diameter and leaf
area. Moreover the highest significant number of leaves per shoot was obtained with Navelina orange cultivar. As
for flowering and fruit set, the highest number of flowers per shoot was obtained for Nave-late orange cultivar, while
Navelina orange cultivar significantly has the highest initial and final fruit set percentage. Leaves of Lane-late orange
cultivar significantly has the highest nitrogen, phosphorus, potassium, iron and manganese, moreover leaves of
Nave-late orange cultivar recorded the highest content of calcium and magnesium, while Nave-late orange cultivar
significantly has the highest leaf content of zinc, copper and boron. Concerning the changes in endogenous total
indoles and phenols for leaves and flowers through flowering and fruit set stages, obtained results showed that it's
affected by type of navel orange cultivar and the physiological stage of organ for both seasons. As far leaf total
indoles content, steadily increased in Navelina and Nave-late orange cultivars leaves and flowers by time till reached
to the highest values in May, then gradually decreased by time till reached to the lowest values during June.
Meanwhile, endogenous indoles of Lane-late orange cultivar take an adverse line, which steadily decreased during
May, then gradually increased till June. With respect to flowers indoles content, all navel orange cultivars have
gradually decreased till reached to a lower concentration during May. As for leaf phenols content, all navel orange
cultivars steadily have increased by time till reached to a higher concentration, during June. Finally, as for flower
phenols content, Navelina orange cultivar steadily increased by time till reached to a higher concentration. In
contrary, Nave-late and Lane-late orange cultivars gradually decreased till reached to a lower concentration, during
May. As for the results of the anatomy studies, which showed that, Navelina Navel orange cultivar, buds started to
change from vegetative flowering and fruit setting earlier about from 2-3 weeks than the other Navel orange
cultivars. Therefore, it can be conclude that, for increasing navel orange area and expanding marketing of fruits, it
can be cultivate Nave-late, Lane-late or Navelina for to its distinct characteristics under Egyptian conditions.