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The potential of hot water dipping (HWD) at 41±1°C for 20 min or at 50±1°C for 5 min and pre-storage conditioning (6 days at 16-18°C and 45-65% RH) treatments to control chilling injury (CI) and decay of W. Navel and Valencia Late oranges during cold quarantine at 1°C and 85-90% RH for 20 days, subsequent storage at 10°C and 85-90% RH for 20 days (as a transit period) and an additional 20 days of simulated marketing period (SMP) at 20±2°C and 40-65% RH was investigated over 2 harvest seasons (2006/2007 & 2007/2008). Untreated fruits were used as control. We studied their effects on various other postharvest quality parameters such as weight loss, juice %, soluble solids content (SSC), total acidity (TA), ascorbic acid (VC), and reducing sugars, free phenols, peroxidase (POX) and catalase (CAT) activities, and ascorbic acid oxidase (ASAO). After SMP, HWD treatments reduced the incidence of CI in W. Navel (4.2-13% versus 29-33% in control and 12-21% in conditioning treatments) and Valencia (0-27% against 60-63% in control and 60-67% in conditioning treatments). HWD treatments effectively prevented the incidence of decay in both cultivars in all storage stages, while conditioning one reduced it in W. Navel to 17-13%, against 25% in the control, although in Valencia, a very little insignificant decay % was found (3-7%). HWD treatments reduced the rate of weight loss in both cultivars, while conditioning one reduced it in Valencia, only. In addition, HWD treatments mostly increased VC content, especially in W. Navel, while reduced ASAO activity. HWD treatments increased free phenols content in both cultivars, as compared with control and conditioning treatments, although the last increased it as compared with control. HWD at 41°C for 20 min was more effective than at 50°C for 5 min in this respect. All treatments significantly increased POX and CAT activities, whether in fruit peel or juice of both cultivars as compared with control. HWD at 41°C for 20 min treatment was more effective in this respect. Generally, the reduction in chilling injury % was paralleled to higher POX and CAT activities in fruit peel and juice, and free phenols in juice, this may explain how and why the treatments reduced CI incidence. Overall, it is concluded that short postharvest HWD treatment is preferable, since it effectively induced tolerance to cold temperatures in W. Navel and Valencia Late oranges without impairing any other postharvest qualities.

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Vegetative growth, yield and fruit quality of "Hernandina" clementine (as newly introduced cultivar in Egypt) grafted on Sour orange (the most common rootstock), Cleopatra mandarin, Carrizo citrange and "Swingle" citrumelo were evaluated in a private farm at "Wady El-Mullak" region, Ismailia Governorate during 2004/2005 and 2005/2006 seasons."Hernandina" clementine trees budded on Carrizo citrange showed higher vegetative growth parameters (canopy circumference and diameter, tree volume) than those on Sour orange, "Swingle" citrumelo and Cleopatra mandarin rootstocks, except the tree height which was similar to those on other rootstocks (except Sour orange which was significantly lower). The highest affinity was found with Sour orange, followed by Cleopatra mandarin and Carrizo citrange without significant differences among them, while the lowest affinity was found with "Swingle" citrumelo.Trees on Carrizo citrange produced higher yield than those on Sour orange, Cleopatra mandarin and "Swingle" citrumelo rootstocks. The trees grafted on Carrizo citrange had the highest average yield of the two seasons (29.51%, 24.55% and 13.55% over those on Cleopatra mandarin, Sour orange and "Swingle" citrumelo, respectively). Trees on Cleopatra mandarin showed a significant higher alternate bearing index (24.87%) as compared with those on other rootstocks.Juice SSC, acidity, SSC/acid ratio and ascorbic acid contents were significantly affected by rootstock. The fruits from trees budded on Carrizo citrange showed the highest SSC, while those budded on Sour orange had the lowest SSC and highest acidity. The lowest maturity index was achieved by fruits from trees grafted on Sour orange as compared with those on the other rootstocks; however, the highest maturity index was clear in fruits from trees on Carrizo citrange and "Swingle" citrumelo rootstocks.Considering the tree growth rate, scion/stock affinity, yield and fruit quality; Carrizo citrange and Cleopatra mandarin can be considered as the most promising rootstocks for 'Hernandina' clementine under the Egyptian conditions.

Seeds of Sour orange (SO) and Carrizo citrange (CC) rootstocks were treated by soaking for 24 h in tap water, Ca ++ NO3 at 0.2%, KNO3 at 0.2%, Goëmar (biostimulant) BM86 at 0.3 and 0.5%, Goëmar MZ63 at 0.5%, GA3 at 50 ppm or control (directly sowing) in a trial to improve the emergence and growth of seedlings aiming to produce good transplants. The seeds were sown under plastic house during February of 2006 and 2007 seasons. SO seeds had higher emergence percentage, emerged faster and gave lower number of seedlings/seed than those of C.C. Moreover, seedling of S.O was higher at 70 days after sowing, but after 6 months those of CC were the highest in stem length and diameter, and the lowest in fresh and dry weight. On the other hand, the leaves of CC had higher N content in both seasons and lower P content in the first season only, compared to SO. Treatments with Goëmar BM860.3% increased the emergence % (90.8 & 92.8%) as compared with all other ones, followed by GA3 (85.0 & 88.5%), tap water (86.5 & 88.0%) and KNO3 (84.7 & 85.8%). No significant differences were found in the emergence % among Ca ++ NO3, Goëmar BM86 (0.5%), Goëmar MZ63 (0.5%) and the control treatments. The average number of days required to complete the seedling emergence was reduced by soaking the seeds in tap water before sowing (emergence rate were 34.9 & 36.3 days, in both seasons, respectively). After 6 months from sowing, Goëmar MZ63 (0.5%) treatment produced seedlings with stem length (31.2 & 36.5 cm) higher than those of control one (28.4 & 33.7 cm). Seedling fresh and dray weights increased with tap water treatment compared to the control and GA3 ones. On the other hand, leaf N content increased with Ca ++ NO3 and Goëmar MZ63 (0.5%), while P leaf content was higher with all treatments, except KNO3 and GA3 compared to the control.

Hernandina' clementine, 'Clemenules' clementine and 'Nova' mandarin budded on sour orange rootstock were produced in a screenhouse and planted in the field under drip irrigation system during October 1999 in a private orchard at "Wady El-Mullak" region, Ismailia Governorate (Latitude, 30°36' N; longitude, 32°14' E; Altitude, 10 m above sea level), which is one of the largest citrus production region in Egypt. All cultivars were planted at 2 x 5 m and 5 x 5 m. Annual fruit production, cumulative and average yields per tree and per feddan were estimated during five seasons, starting from 3 rd year after planting (YAP) to 7 th YAP (2006YAP ( /2007. Tree height, canopy diameter and circumference, tree volume, and trunk girth were determined in the 6 th and 7 th YAP.Trees planted at 2 x 5 m were the tallest, but the canopy diameter and circumference, and volume of trees planted at 5 x 5 m were the largest. On the other hand, trees of 'Nova' mandarin had the lowest canopy diameter and circumference, while 'Clemenules' clementine trees had more height and volume.Initial yields per tree (3 rd and 4 th YAP) from planting spacing of 2 x 5 m were higher than those from the wide spacing, but starting from 5 th to 7 th YAP the situation was inverted. Cumulative yield for the first 5 years of production and the average annual yield per tree revealed the superiority of the wide spacing. On the contrary, the yield per feddan (4200 m 2 ) from trees planted at 2 x 5 m was about 454%, 221%, 137%, 76% and 90% greater than those planted at 5 x 5 m in the 3 rd , 4 th , 5 th , 6 th and 7 th YAP, respectively. Cumulative yield per feddan from closely planted trees was 40 t (117%) more than from widely spaced.'Hernandina' clementine produced more yields in the 3 rd and 4 th YAP compared with other cultivars; while 'Clemenules' clementine was the highest in the 5 th YAP. 'Nova' mandarin produced the highest yield in the 7 th YAP, while in 6 th one were statistically similar to those of 'Hernandina', which produced the highest yield. Cumulative and average annual yield per tree indicated that 'Hernandina' and 'Nova' cultivars were more productive than 'Clemenules' under the conditions of this study. On the other hand, 'Clemenules', 'Hernandina' and 'Nova', as new citrus cultivars in Egypt performed satisfactory in a highdensity planting (2 x 5 m) through 7 year after planting, despite of 'Nova' mandarin was the most excellent, followed by 'Hernandina' and 'Clemenules' (cumulative yields were 82, 71 and 68 t/feddan, for the three cultivars, respectively); and could continue until the productivity per feddan decrease compared to normal spacing.

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