| A note on effect of gamma irradiation in wheat
R.K. CHOWDHURY* Haryana Agricultural University Regional Research Station, Bawal, 123501, India. The induced mutations have been used in various crop plants to improve various characteristics. MIKE (1975) has given a list of crop cultivars evolved through induced mutagenesis. GAUL (1964) described plant breeding as the controlled evolution. By mutations, plants can be genetically improved. However, future importance of mutation breeding depends on whether it succeeds in securing better control of the whole complicated process of "Obtaining mutants" starting with mutation induction to selection. Generally, all type of mutagens reduce seed germination and increase seeding lethality (CAMPOS et al. 1960 and other). It has been attributed to be the killing effect of the mutagen. In some crop plants increase in germination has also been reported at lower doses (FUJII & MATSUMURA 1966 and others). In the present study, dry seeds of six well adapted varieties having 12 percent moisture were exposed to different doses of gamma irradiation as elsewhere reported by CHOWDHURY (1982) to see the effect of gamma irradiation on germination and survival and also to isolate desirable mutants in the succeeding generations. Percent germination and survival were calculated for each variety/dose taking control as 100 percent. The relative increase/decrease in seed garmination and survival percentages in each dose/variety have been given in Table 1 and plotted in Figure 1. It is clear from this table that the germination was reduced in all the doses compared to their control. The germination was, however, increased in 10 KR dose of WH 147 and Sonalika to 6.3 and 2.7 per cent respectively. There was a symmetric reduction in germination in all the varieties towards higher doses of gamma rays (Fig. 1). Meximum reduction was observed in HD 2009 followed by C 306 and WH 157. Variety WH 147 was least effected. It was interesting to note that the maximum increase in seed germination at 10 KR level was noticed in variety WH 147 where the seed germination in control was lowest (88.7 per cent) compared to other varieties. This shows that the lower doses of gamma rays may increase seed germination particularly in those genotypes where seed germination is low. However, in other genotypes, gamma irradiation may have deterimental effect on germination even at lower doses. The different genotypes showed different response towards gamma irradiation. The dose effects were highly significant. Also, the dose x genotype interaction was significant. |
| * Present address: Economic Botanist (Wheat), Haryana Agricultural University, Hissar, 125004 (India). |
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