Plant mutation breeding in agriculture.

Abstract

A mutation is a sudden heritable change in the DNA in a living cell, not caused by genetic segregation or genetic recombination. Mutation breeding is the purposeful application of mutations in plant breeding. Unlike hybridization and selection, mutation breeding has the advantage of improving a defect in an otherwise elite cultivar, without losing its agronomic and quality characteristics. Mutation breeding is the only straightforward alternative for improving seedless crops. Since the first release of mutant cultivars that resulted from basic mutation research in Europe, mutation breeding has found a niche in plant breeding because of these advantages. Methodologies for mutation induction have been improved in main crops for both physical and chemical mutagens, and selection methodologies for mutant populations have been described. New mutagenic agents such as ion-beam radiation and cosmic rays are being investigated and a hitherto undescribed wide spectrum of mutations has been observed. Nevertheless, alkylating agents and ionizing radiation are still popular. The development of robust in vitro techniques for many crop species has contributed to improving the efficiency of mutation breeding. The ability to handle large mutagenized populations in a confined space, faster progeny turnover in vegetatively propagated species and the ability to screen for several biotic and abiotic stress factors in the culture environment make in vitro approaches very efficient. Mutant screening has undergone revolutionary changes in the past decade with reverse genetic approaches taking precedence. Therefore, integration of mutation techniques with molecular approaches is providing exciting opportunities for modern plant breeding.

Applications of Ionizing Radiation in Mutation Breeding

“…Ionizing radiation could cause several DNA damages randomly; therefore, several mutations (from point mutation to chromosome aberrations) could be induced. Over 3000 mutant varieties of major crops have been reported to be developed by ionizing radiation [2,16].…”

“…Therefore, they have also been exploited by man in the agricultural processes of species domestication and crop improvement. As a new approach, manipulation of the cultivars through alternative techniques such as mutation breeding and Biotechnology are useful for especially some fully sterile plants [2].…”

“…However, some mutagenic agents are known to induce mutations as an alternative to low incidences of spontaneous mutations to increase genetic variability by increasing the frequency of mutations. Using of mutagens propose the possibility of inducing desired characters that cannot be found in nature, in a variety or lost during the evolution [2].…”

Induced Mutations and Crop Improvement

“…Increase in the crop yields attributed to altered plant architecture to suit modern agronomic practices is also a result of induced or incorporated mutant genes into the old cultivars (Pathirana 2011 uted with abiotic stress tolerance ( http://mvgs. iaea.org ).…”

The Use of Gamma Irradiation in Plant Mutation Breeding

“…After that, a few researchers reported spontaneous variation in plants between 1590 and 1968 [6]. However, the first publications of induced mutations (through X-rays) for the plant breeding was published 89 years ago by Muller and Stadler [7,8]. As a result of these studies, mutation breeding as a new approach was added to other plant breeding methods.…”