Generation of promising lines of bean (Phaseolus vulgaris L.) induced by mutations to increase competitiveness of Costa Rica

Biotechnology techniques combined to molecular and nuclear energy (Biotec/EN) can be used for inducing mutations in plants and therefore to develop new lines of crops with new characteristic such disease resistance, better quality or enhanced production. In Costa Rica, there is a National Project on Technical Cooperation of the International Atomic Energy Agency (IAEA) for the improvement of beans. This crop is the main source of protein and folic acid in the diet of Costa Ricans. The fungal disease known as Web blight (Thanatephorus cucumeris), is the main constraint in the production of the crop and there are not any naturally resistant lines. For this reason the main objective of this project is to select resistance lines and contribute to the increased competitiveness of the national production. In addition, the project will provide an effective technology transfer to the agricultural sector in Costa Rica and enhance the quality of life for farmers and the strengthening of alimentary security in the country. Seeds of 'Bribri' and 'Brunca' bean varieties were supplied by the Experimental Station Fabio Baudrit Moreno of the University of Costa Rica. A method has been improved for in vitro culture in the regeneration of the seedlings. The embryonic shoot apex irradiated with 0, 10, 20 and 30 Gy were cultivated in culture medium MS without growth regulators. The plants were evaluated at 15, 30, 60 and 90 days after transplanted. The variables evaluated were: survival rate, percentage of abnormalities, number of leaves, plant size, number of flowers per plant, number of seeds per plant, seed size, fresh weight of seed per plant and flowering days. Lines resistant to Tanathephorus cucumeris through disconnected leaves were evaluated and selected. The currently obtained results are preliminary, because the experiments have not been finished yet. We hoped that this research project will help promote interest in the coordinated use of biotechnology and nuclear energy for peace. (author)