| Differential effect of radiation in varieties of bread
wheats R. P. CHANDOLA Govt. Agriculture Research Farm, Durgapura, Jaipur, Rajasthan, India Effects of gamma-radiation on germination studies in six varieties of bread wheats (five hexaploids and one tetraploid) viz. R. S. 31-1, C591, R. S. 9-11, Jaipur Local, Kharchia (6x) and Malvi Ekdania (4x was reported earlier in this journal (CHANDOLA, 1966). An account of further critical observations on survival, seed and pollen fertility in these varieties is being given presently with an additional infromation available on some of these varieties on their behaviour towards X-irradiation and pile neutron treatments in the M1 generations. Pile neutron treatment was secured for the seed material from the Atomic Energy Reactor at Trombay, Bombay and the X-irradiation was done at the Division of Genetiss. Indian Agricultural Research Institute, New Delhi. As these various sources of irradiation could not be compared among themselves in terms of total energy disseminated in each treatment it is considered worthwhile to at least compare the effectiveness of different doses in the same treatment in respect of the various varieties treated. Pollen fertility as measured by stainability in acetocarmine was calculated in some M1 plants belonging to each treatment. Seed fertility was studied from the earheads of the individual plants belonging to the M1 generation by counting the total number of seeds per spike and calculating the average per spikelet. Observations from such five spikes drawn at random were taken to estimate the seed fertility per plant and in case of very low seed fertility in any plant readings from all the spikes were taken. These data are given in Table 1. First column of Table 1 shows number of seeds actually sown in any control or treatment and the number of plants that finally survived, the latter being given in parenthses. From these data apparently, there seems to be a general decline in survival with the increasing dose in the same kind of treatment in any one variety as compared to its corresponding control. There is an identity in survival perecentage of the treatment 10,000r gamma-rays in Jaipur Local and Kharchia varieties of the hexaploid wheats and other varieties show a difference ranging from the lowest percentage in var. Malvi Ekdania (4x) being 73.7% to the highest in var. R. S. 9-11 being 97.8%. The last survival was observed in R. S. 31-1 and maximum in Malvi Ekdania among the 20,000r gamma-ray treatments. Among the 30,000r treatments the minimun survival was shown by var. Malvi Ekadania being 8.1% and var. Jaipur Local which has a survival percentage of 82.4. In the pile neutron treatments of the three varieties(R. S. 31-1, C591 and Malvi Ekdania) the dose 4.5 x 1012np/cm2 showed a rise in the survival percentage than the lowest dose of 1.5x 1012np/cm2 in vars. R. S. 31-1 and Malvi Ekdania being 95% and 74% respectively. In rest of the higher the dose the lower is the survival is the rule in this kind of treatment. In the X-ray treatments of 16,000r of the two varieties R. S. 31-1 and C591 the percentage of survival is reduced as compared to control almost to an identical degree. |
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