[en] Seeds from six varieties of Gossypium hirusutum and from one variety of Gossypium barbadense were cultured in plastic containers (20 x 60 x 30 cm) with compost (Terfgroup, Netherlands). Germination readings were taken 14 days after culture, where plants with first true leaf was chosen for readings. The highest percentages of germinations were 83.3 (C6040) and 80 % (Rakka 5). Seeds of Rakka 5 were subjected to gamma radiation (⁶⁰Co) with radiation activity of 4 kci using the Gamma cell (Isolvated, made in Russia) at the Radiation Technology department at the AECS. The following doses were used in a rate of 1.8548 k Gry/h: 100,150, 200, 250, 300, 350,400 and 500 Gry. On the other hand, seeds of C6040 were subjected to 100,150,200, 250 and 300 Gry. The results indicated the effects of gamma radiation doses on germination rate, plant height, distance between cotyledons leaves and first true leaf and flowering time.(author)

[en] The aim of this study is to investigate the effects of seeds exposure to high doses of ultraviolet radiations (UVRs) on the germination of the cotton variety Deir Al-Zour 22 (stored old seeds) under natural and abiotic (salinity and drought) stresses. Seed samples were irradiated by ultraviolet radiation using a radiation platform that consisted of high pressure mercury arc lamp, an aluminum mirror and a sample supporting stage, which permits to choose a suitable exposure level. Moreover, the effect of seeds irradiation duration on germination was studied. As a result of the observed stimulatory effect, both 8 and 12 minute exposure periods were selected for further analysis. The results indicated an increased tolerance level of germinated cotton plants under abiotic stresses such as low temperatures, salinity and drought after UV radiation. Data also showed an increase in gene expression of VPP and DHN genes following the UV radiation exposure. This suggests a potential increase in DHN and H+-PPase proteins which capture and accumulates free radicals in plant cells vacuoles, along with their role in osmotic regulation which leads to plant tolerance to stresses (author).

[en] Flowering behavior and fiber quality traits were analyzed of six Gossypium hirsutum L. varieties and one G. barbadense variety that were cultivated in two environmentally different locations. Records of days after planting (DAP) at first floral bud emergence, DAP at first floral opening, plant height at first flower and nodes above white flower (NAWF) were analyzed statistically to study flowering behavior in both locations. Fiber traits were tested and records of micronaire, fiber length, strength, cohesion, elongation, ginning percentage, and weight of seed cotton were statistically analyzed to look for significant differences and correlations. Earliness and a decline in fiber strength, and fiber cohesion were obtained in varieties cultivated in Soujeh accompanied with an increase in ginning percentages. Uniquely, fiber elongation showed no significant differences in varieties between the two environments in both seasons. Our results indicated that stability in some fiber traits such as, micronaire, fiber length, strength and cohesion was a variety specific. Evidently, fiber elongation in our work was not affected by cultivation managements and environmental conditions which suggest the solid genetic bases that control this trait. (author)

[en] The effects of variety, growth regulators, sucrose, and low doses of gamma irradiation on the production of potato (Solanum tuberosum L.) microtubers in vitro were investigated. Nodal segments from virus free explants of 3 potato varieties were placed on six different media and irradiated with 4 doses of gamma radiation (2.5, 5, 10, 15 Gy).Potato varieties used in the study differed in their ability to produce microtubers. Variety Diamant was the best in microtuber production followed by Draga and Spunta. Kinetin played a significant role in inducing tuberization in vitro especially at a concentration of 4 mg^-1. Tuberization was also enhanced by sucrose especially when its level was increased from 3% to 6%. Irradiating the explants with 2.5 Gy of gamma radiation leads to a significant increase in number of microtubers (34% increase over the control). Weight of microtubers was not significantly influenced by low doses of gamma irradiation or media components. Draga microtubers were the largest followed by Diamant and Spunta. Microtubers resembled mature tubers in shape (Spunta was elongated and Draga and Diamant were round). Size of microtubers was crucial for sprouting in vivo. It is suggested that only microtubers larger than 250 mg (5 mm in diameter) can be used to produce minitubers in vivo. Since 2.5 Gy is a low dose, it can be used to enhance tuberization in vitro without fear of genetic changes in the used varieties. (author)

[en] Seeds from six varieties of Gossypium hirusutum and from one variety of Gossypium barbadense were cultured in plastic containers (20 x 60 x 30 cm) with compost (Terfgroup, Netherlands). Germination readings were taken 14 days after culture, where plants with first true leaf was chosen for readings. The highest percentages of germinations were 83.3 (C6040) and 80 % (Rakka 5). Seeds of Rakka 5 were subjected to gamma radiation (60^Co) with radiation activity of 4 kci using the Gamma cell (Isolvated, made in Russia) at the Radiation Technology department at the AECS. The following doses were used in a rate of 1.8548 KGry/h: 100,150, 200, 250, 300, 350,400 and 500 Gry. On the other hand, seeds of C6040 were subjected to 100,150,200, 250 and 300 Gry. The results indicated the effects of gamma radiation doses on germination rate, plant height, distance between cotyledons leaves and first true leaf and flowering time.(author)

[en] The effect of low doses of gamma irradiation and potato (Solanum tuberosum L.) cultivar on the production of microtubers in vitro were investigated. Nodal segments from virus free explants of three potato cultivars (cv.) were placed on tuberization inducing medium and irradiated with 4 doses of gamma radiation (2.5, 5, 10, 15 Gy). Cv. Diamant produced the highest number of microtubers followed by Draga and Spunta. Irradiation of the explants with 2.5 Gy of gamma radiation led to a significant increase in the number of microtubers (38% increase over the control). Average weight of microtubers was not significantly influenced by low doses of gamma irradiation. Draga microtubers were the largest followed by Diamant and Spunta. Microtubes resembled mature tubers in shape (Spunta was oval and Draga and Diamant were spherical). Size of microtubers was crucial for sprouting in vivo. It is suggested that only microtubers larger than 5 mm in diameter (250 mg) be used to produce minitubers in vivo. Since 205 Gy is a low irradiation dose, it can be used to enhance tuberization in vitro without fear of genetic changes in the used cultivars. (Author)

[en] The flowering behavior and fiber quality traits were analyzed of six Gossypium hirsutum L. varieties and one G. barbadense variety that were cultivated in two environmentally different locations. Records of days after planting (DAP) at first floral bud emergence, DAP at first floral opening, plant height at first flower and nodes above white flower (NAWF) were analyzed statistically to study flowering behavior in both locations. Fiber traits were tested and records of micronaire, fiber length, strength, cohesion, elongation, ginning percentage, and weight of seed cotton were statistically analyzed to look for significant differences and correlations. Earliness and a decline in fiber strength, and fiber cohesion were obtained in varieties cultivated in Soujeh accompanied with an increase in ginning percentages. Uniquely, fiber elongation showed no significant differences in varieties between the two environments in both seasons. Our results indicated that stability in some fiber traits such as, micronaire, fiber length, strength and cohesion was a variety specific. Evidently, fiber elongation in our work was not affected by cultivation managements and environmental conditions which suggest the solid genetic bases that control this trait.(author)