MUTAGENIC EFFECTS ON GAMMA RADIATION ON RICE
Co/sup 60/ irradiation of dry grains (Tjeremas variety of indica type of Oryza sativa) was carried out for the development of mutants of agronomic value for breeding with standard varieties. Progenies of selfed normal and aberrant plants were grown for several generations to detect variations. Doses of 20, 25, and 30 kr did not greatly reduce the percentage of germination while 40 and 50 kr killed most of the seeds. Seedling survival was markedly reduced following 30 and 40 kr, while no seedlings survived 50 kr. Seedling height was reduced following 30 and 40 kr, the plants having only 40% and 20%, respectively, the height of the controls, while following 20 and 25 kr, reduction in height was not great. Of 23 R/sub 1/ variations, 7 mutations were isolated and established in R/ sub 4/ and R/sub 5/ generations, namely, albina, xantha, striped, bushy, spreading, slow-grower, and long awn. The chlorophyll-deflciency mutations and long awn have occurred spontaneously as gene mutations in other varieties but spreading and slow-grower have not been reported. The latter mutants and bushy are promising stocks for rice improvement. The only chromosomal aberration found in progenies of treated plants was heterozygous reciprocal translocation, recognizable by rings or chains of 4 chromosomes at metaphase I. A max. of 3 interchange configurations per cell was observed in highly sterile lines, indicating the possible breakage of up to 50.0% of the bivalents of the complement. (H.H.D.)
- Research Organization:
- Univ. of Philippines, Quezon City
- NSA Number:
- NSA-16-032766
- OSTI ID:
- 4769908
- Journal Information:
- Botan. Gaz., Vol. Vol: 123; Other Information: Orig. Receipt Date: 31-DEC-62
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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