[en] The paper attempts to summarize relevant information on microbiological safety of irradiated foods in the light of previous reports of expert committees and current literature references. After a brief overview of the relative radiation resistance of food-borne microorganisms the importance of microbial load for dose requirement, and the role of post-irradiation conditions, it addresses the following questions: Could selective changes in the microflora caused by non-sterilizing radiation doses make known pathogens more likely to occur, or bring into prominence unfamiliar pathogens? Is it probable that ''mutational'' (including adaptive) changes might make pathogens more virulent, more harmful, or more difficult to recognize, and could new pathogens arise in this way? Is it possible that development of radiation resistant strains might render the antimicrobial irradiation processes ineffective? The present survey of relevant scientific evidence related to these questions reaffirms the basic conclusion of earlier reviews that microbiological safety of irradiated food is fully comparable with that of foods preserved by other acceptable preservation methods. Similar to other preservation processes, gains in microbiological or keeping quality attained by food irradiation can be and must be safeguarded by proper control in the food irradiation facilities and by proper care of the product before and after processing. (author). 99 refs

[en] Genetic variability is required for the plant breeder to select better traits. Mutation induction by radiation and other mutagens is a means of altering genes and creating genetic variability for the breeder. A list is given of the number of mutant varieties of vegetables, fruits and ornamental flowers. Data given in the tables show that using induced mutations, 227 improved varieties of agricultural crops have been developed and released to farmers in 35 different countries. The IAEA has been involved in fostering mutation breeding since its foundation through training and direct research support. The Joint FAO/IAEA Division has published the Mutation Breeding Newsletter for plant breeders all over the world to keep abreast with developments in this field

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[en] Shoot tips of taro cv. 'Bentul' plantlets grown in tissue culture and irradiated at 10 Gy produced many variants. The variations included different lamina traits (shape, orientation, undulations, outline of sinus, color), vein junction color, off shoot number, stolon number, plant height, leaf number, petiole color, leaf blight resistance, corm weight, and taste. The predominant lamina characters induced from gamma-irradiated shoot tip of 'Bentul' Taro were a flat shape with dropping edges, a semi-horizontal orientation with entire undulations, a narrow (< 45 deg.) outline of the sinus, green color, whitish green vein junctions, and dark green petioles with purple tips. This was coupled with 1 off shoot and 1 stolon per plant, 31-40 cm tall plants with 4 leaves, a large tolerance to leaf blight disease, 101-150 g corm weights, and an acrid taste. Three variants (B 43, B 63, B 133) with the best characters were selected. They were early maturing (6 months old) with a heavy corm weight (351-400 g), very tolerant to leaf blight disease (little symptom), and had a good taste (sweet and no acrid). (author)

[en] The objective of this study was to induce mutation in Warty Brassia (Brassia verrucosa Lindl.) through in vitro mutagenesis by treating the bud clusters with gamma irradiation, aiming to select the valuable varieties of Warty Brassia. The following contents were conducted: detecting of genetic polymorphism of the variants by applying RAPD analysis; evaluating the growth of variation forms of Warty Brassia obtaining after irradiation in the nursery stage; selecting desired variations. The results revealed that 9 variants were examined genetic diversity, 8 variants there were genetic differences among 8 variants and original variety. There were differences in the growth potential among morphological variants under nursery condition. The mutants having large pseudobulb, dark green leaves and the mutants having pseudobulb round in shape, short leaves promise to develop mutants strains. Types of mutation were selected and multiply rapidly from generation M_1V_1 - M_1V_3, they retained 100% morphological features of their parents. The study is being conducting to assess the flower color and shape of the mutants derived from Warty Brassia. (author)

[en] A Co-ordinated Research Programme on the Improvement of Vegetatively Propagated Crops and Tree Crops Through Induced Mutations was sponsored by the IAEA between 1972 and 1980. It was based on the recommendations of an FAO/IAEA panel of experts who met in September 1972 and concluded that mutation induction was an appropriate tool for improving genetically crop plants that are not easily improved by cross breeding. Research has been carried out to develop techniques for induction, selection and utilization of mutants in various vegetatively propagated crops. The programme has included a wide variety of plant species in tropical and temperate climates, such as sugarcane, potato, cassava, mulberry, citrus, bananas, apple, cherry, peach, grape, forage grasses, as well as a group of ornamental plants. The present book contains the reports presented by the project leaders at the final Research Co-ordination Meeting organized by the Joint FAO/IAEA Division of Isotope and Radiation Applications of Atomic Energy for Food and Agricultural Development, and held in Coimbatore, India, from 11-15 February, 1980. It also includes a review of the programme with conclusions and recommendations

[en] Sudden, heritable changes in the genetic material, DNA, are known as mutations. Selection of naturally occurring mutations in wild, ancestral species helped humans in the domestication and further improvement of today's crop plants. Although Charles Darwin was unaware in 1859 of variation and mutations in living organisms, his theory of evolution by natural selection assumed variability. Much later, it was established that mutations are the source of biodiversity, and the driving force for evolution. Gregor Mendel in 1865 also used several mutants in his experiments with garden pea to formulate the laws of inheritance. The term mutation itself was used for the first time by Hugo de Vries in 1901 in his mutation theory. Plant breeding based on the science of genetics, as practiced over the past 100 years, exploited the available genetic variability in the primary gene pool of crop plants, and sometimes in related species. This approach enlarged the yield potential of crops several fold. It also a) improved the stability of yield by incorporating resistance to various biotic and abiotic stresses; b) improved quality of the produce; and c) altered the adaptability of crop species, providing opportunities to grow new crops for food security outside their traditional range. Genetically improved seed (or other planting material) is the most significant input for developing sustainable cropping systems for food security and economic growth. Half of the increased productivity of today's crop plants comes from genetic improvements. The other half is contributed by inputs and management practices

[en] Soaked seeds of an exotic variety 5toneville-231 (Gossypium hirsutum L) were treated with gamma rays at 30 kR from ⁶⁰CO source having dose rate of 40 kR per hour and planted in the field as M₁ genera fion during 1984. From the segregating generations, a high yielding mutant was selected and named as NIAB-92. The plant of NIAB-92 is a semi-haily, compact sympodial type of medium stature. It has 0-2 fruit bearing monopodial branches and more number of shorter sympodial branches as compared to the parent, Stoneville-231 and commercial cotton variety NIAB-78. The mutant is early maturing and matures twenty days earlier than the parent 5toneville-231. It has higher yield potential along with desirable fibre properties such as G.O.T.(%), fibre length, fibre fineness and fibre strength. In the comparative yield trials the mutant NIAB-92 significantly out yielded both the prevalent commercial cotton varieties i.e., NIAB- 78 and S-12. At NIAB it gave 15.3 % and 19.1 % higher yield than NIAB-78 and 5-12, respectively, while at farmers fields the increase in yield was 8.8 % and 14.1 % as compared with NIAB-78 and 5-12. The mutant has also shown resistance against leaf curl virus disease. (author)

[en] Cassava is of great economic significance in Zambia due to its increasing role as a food security crop in drought prone areas of the country.Studies to improve the quality of the cassava tuber and the quality and quantity of the planting material using in vitro techniques is being conducted in several areas of Zambia. The preliminary results are encouraging from the field trials conducted so far