الفهرس 
Effect of radiation on seed germinationOnly 14 pages are availabe for public view
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Abstract
This study was conducted in a private Farm in Centerees village , Ashmoon district, Menofiya Governorate during 2005 /06.2006/07 and 2007/08 seasons to study the effect of different doses of gamma –rays on the vegetative growth and flowering characteristic and oil content as well as growth variation of Matricaria chamomolla L.plant. Dry seeds ware irradiated by gamma- rays. Gamma -rays were generated from the Cobalt (Co60) sources installed in Atomic Energy Establishment at Naser city, Cairo, Egypt. The used doses were 0, 2.5, 5, 10, 20, 30 and 40 kr in the two experimental seasons. Irradiated and non irradiated seeds were sown in seedling trays in the nursery on 15th September 2005 and 2006. Seedlings were transplanted on 1 November 2005 and 2006 in plots in the field. The experimental design used was a randomized complete blocks with three replicates. Every replicate contained 7 treatments in the first and the second seasons. Every treatment contained two ridges every one contained 10 plants. The obtained results in the M1-and M2- generations could be summarized as following:- M1-generation 1- Germination percentage was decreased by increasing gamma– rays doses specially at the high doses of 30 and 40 kr which registered the lowest germination percentage but, the highest germination percentage were recorded at the control and 2.5 kr dose in both seasons. 2- There were a significant differences among the different doses of gamma-rays on plant height in both seasons. The best results in plant height were obtained at 5 and 10 kr doses in the first season and at 10 and 20 kr in the second one compared with the untreated plants as well as other doses. 3- The number of branches per plant increased by decreasing gamma – rays doses in the two growing seasons. The highest value of the number of branches/ plant were achieved at 5 and 10 kr in the first season and at 10, 20 kr in the second season compared with control and other doses. 4- Fresh weight of leaves per plant significantly increased as a result of using gamma–rays irradiation especially at 10 kr compared to control and other doses in the two experimental seasons. 5- The highest dry weight of leaves per plant resulted from the dose of 10 kr in both seasons compared to control and other doses. The lightest dry weight of leaves per plant resulted at the control and 40 kr in the first season and at 30 and 40 kr and control in the second season. 6- Gamma -rays at different doses significantly increased fresh weight of stems per plant The heaviest fresh weight of stems per plant were obtained at the dose of 10 kr in the first season and at 20 kr in the second one compared to control and other doses. 7- The application of the different doses of gamma-rays gave mostly significant increases in the dry weight of stems per plant during the two subsequent seasons compared to untreated plants. The heaviest dry weights of stems per plant were obtained at 5 and 10 kr. Meanwhile the lightest one resulted at the control and 40 kr in the both seasons. 8- The fresh weight of total herb significantly increased with increasing gamma-rays dose and reached to maximum values at 10 kr dose followed by 20 kr dose compared to control and other doses which gave lower values in both seasons. 9- The obtained results indicated that irradiating seeds with the different doses of gamma-rays significantly increased dry weight of total herb in the two growing seasons compared to control. The best results of dry weight of the total herb were obtained at 20 kr dose in the two seasons. 10- Days from sowing to flowering decreased by increasing gamma -rays doses especially at 30 and 40 kr doses which yielded the earliest flowering plants. 11- There were highly significant differences among the different doses of gamma rays on the number of inflorescences per plant in the two experimental seasons. The lowest doses resulted a highly significant increase in the number of inflorescence per plant especially at 10 kr in the first season and 20 kr in the second one compared with control and other doses. 12- The irradiated seeds with gamma- rays at low doses resulted in a significant increment in the fresh weight of inflorescences per plant compared with control and high doses. The highest values resulted from the doses of 10 kr followed by the doses of 5 and 20 kr in the both seasons. 13- Dry weight of inflorescences per plant significantly increased by increasing gamma -rays doses up to 10 kr in both seasons compared to the control and other doses then decreased with increasing the doses of gammarays until reached at lowest dry weight of inflorescences per plant at the doses of 40 kr in both seasons. 14- Essential oil percentage slightly increased by using the different doses of gamma rays as comparing with the control in the two seasons. 15- Irradiated plants with gamma rays at most doses significantly increased oil yield per plant compared with control. The highest doses decreased oil yield per plant especially at 40 kr dose. 16- Oil yield/ feddan were increased by using gamma rays. The highest results were achieved from the dose of 10 kr in the two experimental seasons compared to the control and the other doses. 17- The high doses of gamma-rays at 30 and 40 kr significantly reduced pollen viability in the two experimental seasons compared with the control and low doses of gamma -rays. M2- generation 1- The different doses of gamma-rays increased the plant height except 40 kr dose which give a lowest values of the plant height compared with the control and other doses in both growing seasons. 2- The different doses increased the number of branches per plant, except of 40 kr dose which gave lowest values in this respect compared with the control and other doses in both growing seasons. 3- There were significant increases in the fresh and dry weights of leaves per plant as results of using the low doses of gamma- rays especially at 10 kr in the first season and 5 kr in the second season compared with the control and other doses of gamma- rays. 4- Fresh and dry weights of stems per plant increased by increasing gamma ray doses up to 10 k.r in the first season and 5 kr in the second season compared with the control and other doses of gamma rays. 5- Total fresh and dry weight of herb significantly increased especially at 10 kr in the first season and 5 k.r in the second season compared with control and other doses of gamma- rays. 6- Flowering date slightly decreased as a result of using different doses of gamma -rays and individual selection. There are no significant differences between different doses in the two experimental seasons. 7- There were highly significant increases on the number of inflorescences per plant by increasing gamma- rays dose and reached to their maximum values at 10 and 20 kr in both experimental seasons compared with the control and other doses. The lowest values in this respect yielded from the high dose of 40 kr in the first season and control in the second one. 8- Fresh and dry weights of inflorescences per plant highly significant increased by increasing gamma rays doses up to 10 kr in the first season and 5 kr in the second one compared with control and other doses of gamma-rays. 9- The different doses of gamma-rays gave a slight increased on the oil percentage. The best results achieved at 10 kr in both season compared with control and other doses. 10- There were significant increments in oil yield per plant by using gamma -rays especially at 10 kr in the first season and 5 kr in the second one. The lowest results obtained at high dose of 40 kr and control in both seasons. 11- Gamma- rays at low doses increased oil yield per feddan compared with the control and high doses. The best values obtained at the dose of 10 kr in the first season and 5 kr in the second season. Summary 122 Macro mutation. The dose of 10 and 30 kr of gamma-rays were more efficient by inducing variation followed by 30 and 5 kr under the condition of this investigation. The variation selected in M2- generation were: 1- Shape changes. a- Inflorescences without rays florets, this plants had tall stem length, high number and small inflorescences and moderate fresh and dry weight of leaves and Inflorescences, as well as oil percentage the mutant derived from the dose of 10 kr. b- Compressed stem plants, these plants derived from the dose of 5 kr and had a low diameter of all character. 2- Inflorescence color variations. a- Dark yellow inflorescence were observed at the dose of 10 kr. b- Dark blue ray florets were stated at the dose of 10 kr. 3- Earlier flowering mutant were resulted from 30 kr in the first and the second seasons. 4- Growth habit variations. a- Tall plant derived from the dose of 10 kr in the second season. b- High branches plants derived from the dose of 20 kr in the first and the second seasons.