R. Fotouhi Ghazvini, Y. Hammidoghli, Y. Ebrahimi,
Volume 5, Issue 2 (7-2001)
Abstract
In order to produce Tristeza virus-free plants from Satsuma mandarin (Citrus unshiu) cultivars (Ishikawa, Sugiyama and Myogawa), unfertilized ovules of plants suspected of CTV (Citrus Tristeza virus), from Mazandaran Mahdasht orchard were cultured on 4 media.
Embryogenesis of nucellus tissue of ovules from Ishikawa and Sugiyama cultivars on MS medium were 31% and 25% and on MT medium from Ishikawa was 40.5%. Unfertilized ovules of Myogawa did not germinate on all media.
Nucellar embryos of Ishikawa and Sugiyama developed on MT+GA3+ME were 83% and 95%, respectively. Embryo differentiation, leaf and plantlet formation were observed on MT+GA3+ADE+ME medium. In the stage of two leaves, the plantlets’ growth under 1500 lux illumination was twice its growth under 800 lux illumination. Budding of in vitro plantlets from both cultivars on susceptible to Tristeza and virus-free seedlings of Key Lime did not show any infection by Tristeza.
M. J. Moghbeli Hanzaii, E. Tafazoli,
Volume 6, Issue 3 (10-2002)
Abstract
Alternate bearing is a key factor in limiting citrus production. Chemical controls have proved to be the most effective solution to this problem. Two different experiments were conducted to study the effects of different growth regulators (GA3, NAA, Ethephon) and urea on alternate bearing control in Kinnow mandarin (Citrus reticulata). In the first experiment, GA3 at concentrations of 0, 25, 50, 75 and 100 mgl-1 were applied 3 times during late autumn and early winter 1993 on off trees. Flowers reduced as a result of GA3 application in the following spring but increased in the second spring. Best results obtained with 50 and 75 mgl-1. In the 2nd experiment thinning agents: NAA (0, 100, 200 and 300 mgl-1), ethephon (0, 100, 200, 300 mgl-1) and urea (0, 4, 8 and 12%) were sprayed to the trees on on-year, when the fruitlets were about 0.75-1 cm in diameter. The results indicated that urea had no effect however, both NAA and ethephon were effective on thinning of fruits and control of fruiting. Ethephon at 200 and 300 mgl-1, and NAA at 400 mgl-1 gave the best results.
S. Rastegar , M. Rahemi,
Volume 11, Issue 42 (1-2008)
Abstract
Navel oranges and Clementine mandarin are classified as early cultivars and when fruits are left on the trees, fruit firmness and juice content will decrease. Plant growth regulators have been used to improve fruit quality. Gibberellic acid (GA3) and 2,4-D isopropyl ester sprays were used to increase juice content ,peel firmness and delay senescence in Navel oranges and Clementine mandarin. Factorial experiments were arranged in a complete randomized block design with three replications and each block consisted of three trees. Chemicals were sprayed on the branches (north and south of each tree) with 10 liter sprayer to the point of run-off during fall of 2004 and 2005 ,in a commercial orchard in Jahrom in the south east of Fars province, Iran . In both years of study, GA3 at 100,150 and 200 mgl-l and isopropyl ester 2,4-D at 8,12 and 24 mgl-1 were sprayed on September 30 (diameter of Navel 64 mm and diameter of Clementine 46 mm), October 14 (diameter of Navel 69 mm and diameter of Clementine 48 mm ) and November 7 (diameter of Navel 70 mm and diameter of Clementine 50 mm) and fruits of Navel oranges and Clementine mandarin were harvested 45 and 35 days after last the spray treatment, respectively . The results of experiment revealed that Navel oranges responded better with second application (Oct.14, diameter 69 mm ) and Clementine mandarin with the first application (Sept.30, diameter 46 mm ). Juice content and fruit firmness at harvest increased. GA3 increased juice content even better than 2,4-D isopropyl ester but delayed senescence, 2,4-D was more effective in increasing fruit sizing in both cultivars. GA3 at 150 and 200 mgl-1 and 2,4-D at 24 mgl-1 when compared with the untreated resulted in highest juice content of fruits.
