Venus Ebraheem Hasan*(1) ,Ali Essa Elkhateeb(1) and Dr.Hasan Yosef Khojah(2)
(1) General Commission Agriculture Scientific Research- Lattakia
(2) Tishreen University- Agriculture College- Horticulture Department- Syria.
(*Corresponding author: Venus Hasan. E-Mail: venushasan80@gmail.com).
Abstract:
The study was conducted during 2019-2020 at the Agricultural Scientific Research Center in Lattakia.Poncirustrifoliata were used as (Pollen Parent), Cleopatra, and Sour orange as (Seed Parent). For getting F1 seeds; and its seedling tolerance of chilling. These seeds were sown in agricultural pots, then the seedlings were transferred in February to a temperature controlled refrigerator, where they were exposed to cold gradually reaching (2-)°C and then to (10-)°C. As a result, cold stress (2-)°C caused in the death of about 50% of the tested seedlings, and when the temperatures were reduced to (-10)°C, led to damage to the remaining seedlings, and the percentage of damage reached up to (30%) of the plants, but these seedlings regained its life in the next growing season and continued its activity,Some growth indicators were calculated, the average length and diameter of the plant, the hybrids produced by the female Cleopatra gave the best results, especially the hybrids (210, 201, 233 and 220). the height reached 100 cm in the hybrid (210), as for the damage percentage, it ranged between 7% in the hybrid with sour orange 322 to 30% in the hybrid with Cleopatra (210, 204, 200, 203 and 202),Proline index, showed that the accumulation of proline began at stress (2-)°C with significant differences in comparison before and after exposure to cold, and at a temperature of (-10)°C. The accumulation increased at the surviving plants and the amount of accumulation correlates with the severity of stress, as the accumulated amount of proline reached to more than (2.2 mg / g) in the hybrids with Cleopatra (233, 243, 210, 202 and 240), and more than (2.60 mg / g) in the hybrids with sour orange (300, 320 and 322).Regarding the total chlorophyll index, the highest values were in (322) and (202), with significant differences between the amount of chlorophyll at (2-)°C and its quantity at (10-)°C, and it was found when calculating the specified difference among the studied hybrids in terms of total chlorophyll values was the superiority of the hybrids 322, 320 and 202 over the rest of the hybrids.
Key words: proline, chilling Stress, Chlorophyll, Poncirus trifoliate.
Full paper in Arabic: PDF