Abstract
The horticultural adaptability and performance of 'Parent Washington Navel' (Citrus sinensis (L.) Osbeck) orange trees were evaluated for seven years on nine commercial rootstocks in the Najran area of Saudi Arabia. Fruit yield, fruit size, peel thickness, percentage juice, soluble solids and acid were measured. Trees on Volkamer lemon (VL), Citrus macrophylla (CM) and rough lemon (RL) were the most productive, whereas trees on Swingle citrumelo (SC) and Cleopatra mandarin (Cleo) were the least productive. Trees on sour orange (SO), Carrizo citrange (CC), Citrus Taiwanica (CT), and Amblycarpa (Amb) were intermediate in fruit production. The largest fruit were from trees on VL, CM and RL, while the smallest fruit were on trees budded on Cleo and SO. Peel thickness was the highest in fruit collected from trees on RL and the lowest in fruit collected from those on Cleo and SO. Fruit from trees on Cleo had the highest juice content while those from trees on RL had the lowest juice content. Fruit from trees on CC and SO accumulated the highest soluble solids and fruit from trees on CM, CT, RL, and VL accumulated the lowest soluble solids. Overall, trees on vigorous rootstocks (VL, CM, RL) performed better and were more productive and more profitable than trees on other rootstocks. Trees on SC and Cleo performed the poorest.
