Mutation breeding

About: Mutation breeding is a research topic. Over the lifetime, 531 publications have been published within this topic receiving 6730 citations. The topic is also known as: variation breeding.

Use of neutron irradiations in the brookhaven mutations program

Abstract: Many plant species were irradiated with x rays, thermal and fast neutrons, andd gamma radiation during the past 10 yr of the cooperative mutations program and adjunct mutation breeding program. Four major concepts and/ or approaches related to the use of mutagenic agents in plant breeding that have evolved are discussed. It was concluded that outcrossing between treated and nontreated populations must be reckoned with, and consequently the two populations should be separated before a true measure of mutation induction can be ascertained; chromosome rearrangement studies are useful, with particular emphasis on inducing disease resistance; work concerned with tissue reorgandization and rearrangement as related to chimera production and basic understanding of tissue ontogeny, particularly with fruit crops andd horticultural crops is promising; and the effectiveness of responses of plant tissues to neutrons and other mutagenic agents is extremely variable and more basic work is needed before the full potentialities of mutation breeding as a tool in crop improvement can be appreciated. (auth)

Frequency, Spectrum, and Stability of Leaf Mutants Induced by Diverse γ-Ray Treatments in Two Cymbidium Hybrids.

Abstract: Ionizing radiation combined with in vitro tissue culture has been used for development of new cultivars in diverse crops. The effects of ionizing radiation on mutation induction have been analyzed on several orchid species, including Cymbidium. Limited information is available on the comparison of mutation frequency and spectrum based on phenotypes in Cymbidium species. In addition, the stability of induced chimera mutants in Cymbidium is unknown. In this study, we analyzed the radiation sensitivity, mutation frequency, and spectrum of mutants induced by diverse γ-ray treatments, and analyzed the stability of induced chimera mutants in the Cymbidium hybrid cultivars RB003 and RB012. The optimal γ-irradiation conditions of each cultivar differed as follows: RB003, mutation frequency of 4.06% (under 35 Gy/4 h); RB012, 1.51% (20 Gy/1 h). Re-irradiation of γ-rays broadened the mutation spectrum observed in RB012. The stability of leaf-color chimera mutants was higher than that of leaf-shape chimeras, and stability was dependent on the chimera type and location of a mutation in the cell layers of the shoot apical meristem. These results indicated that short-term γ-irradiation was more effective to induce mutations in Cymbidium. Information on the stability of chimera mutants will be useful for mutation breeding of diverse ornamental plants.

Genetic Diversity in Protoplast- and Cell-Derived Plants of Potato

Abstract: In the past decades, potato breeding research has been mainly focussed on the introduction of genes for disease resistance. Reduction of the ploidy level from tetraploid to diploid (Hougas and Peloquin 1957) and even to monoploid (Jacobsen 1978 a) opened the way to transfer such important resistance genes more easily from diploid wild species into cultivated potato. Despite all breeding activities, old varieties like Bintje in the Netherlands (Anonymous 1984) and Russet Burbank in the USA (Shepard et al. 1980), are still used and they cover a relatively large part of the area cultivated with potato. Because of the use of fungicides, nematocides and the production of healthy seed potatoes, these varieties, highly susceptible to pests, have survived all alterations of cultivation and have, therefore, stayed attractive for the farmer. Negative characters of these varieties have not been removed by classical mutation breeding (Shepard et al. 1980).

Problems and Prospects of Banana Breeding in India

Abstract: Banana breeding programme in India involves maintenance of various genetic resources of banana, of which triploids constitute the maximum share over diploids or tetraploids. RAPD studies conducted in these clones exhibit many distinct genotypes. During a hybridization programme, although many crosses were made, seed set and seed germination were relatively poor in many crosses. Male fertility in banana hybrids could be assessed by pollen output per anther; pollen viability and pollen size, which vary from cross to cross, and also from ploidy to ploidy. Ploidy levels in hybrids are estimated by phenotypic appearance (scoring technique) and confirmed either by stomatal density, size and number of chloroplast per guard cell pair or root tip mitosis. However, flow cytometry appears to be the most reliable method in many disputed cases. Generation of parthenocarpic hybrids depends largely upon selection and utilization of parents with parthenocarpic pedigree in a breeding programme. Evaluation of hybrids and parents indicated the nature of inheritance with respect to plant height and suckering habit but no definite trend could be ascribed to the traits of bunch orientation. Diploid x Diploid breeding approach has led to identification of a superior triploid hybrid, NPH 02-01, while Triploid (with AB)xDiploid approach has led to the development of a promising diploid hybrid H.212 and a triploid hybrid H.96/7 (ABB). Similarly, the Triploid x Diploid breeding programme resulted in development of many potential tetraploids that need further improvement. Innovative breeding approaches through in vitro mutation breeding and in vitro polyploidazation resulted in the development of many potentially useful variants. Breeding for resistance against biotic stresses such as Fusarium wilt and nematodes holds promise in banana, and, biochemical mechanisms for resistance in resistant genotypes/hybrids have been elucidated.