Showing papers on "Mutation breeding published in 1997"

Mutation effect of high altitude balloon flight on rice and green pepper seeds.

Abstract: Dry seeds of rice and green pepper were carried in the basket of a high altitude balloon to 30-40 km for 8 h. The treated seeds were planted on the ground and characters of these seeds and their progenies, such as development, fruiting, disease resistance were observed. The results showed that the SP2 generation of the treated rice showed strong mutation. A Japonica male fertility restorer rice line was found out. It could be hybridized with sterile line of Indica rice, and their progeny had strong hybrid vigor, high setting percentage and good plumpness of grain. Disease resistance, high-yield, big-fruit and high vitamin C content strains were selected from the progenies of treated green pepper seeds. The above results indicated that the special conditions in high altitude could produce a variety of mutations and most of them are hereditable. Therefore, high altitude balloon flight can be used as a new method of mutation breeding.

Space-Induced Mutations for Crop Improvement

Abstract: The space-induced mutations and their applications to crop improvement are comprehensively reviewed. Space provides a special environment with supervacu-um, microgravity and strong cosmic radiation. Experimental data showed that space environment conditions may affect plant growth and development as well as induce genetic changes of crop seeds. The frequency of chromosomal aberrations were greatly increased in seeds carried into space and later germinated on the ground. More multiple chromosomal aberrations were observed in seeds hit by HZE particles of cosmic radiation in space, while similar aberration increases were found in seeds not hit in flight, and the longer the seeds were kept in space, the higher the frequency of chromosomal aberrations was, implying that the combined effects of both cosmic radiation and microgravity or other space-flight factors were the main causes of genetic changes in space-flight seeds. Good achievements have been made by space-induced mutations in crop improvement, especially in sweet pepper, rice and wheat, some very useful and rare mutants which might make a great breakthrough in crop yield improvement have been obtained. It was concluded that crop space-induced mutation breeding can be an effective way in both breeding new cultivars and creating distinctive genetic resources because of its wide mutation spectrum, high frequency of useful genetic variation as well as short breeding period.