The role of mutation breeding on plant improvement in Mexico

In Mexico promotion of radioinduced mutation breeding started in 1974. Further research on advanced mutant lines allowed to obtain new varieties. 'Centauro' and 'Bajio Plus', are wheat varieties with increased yield and tolerance to lodging, derived from 'Salamanca' seeds irradiated at 500 Gy, obtained by Colegio de Postgraduados. Regarding to soybean, Instituto Nacional de Investigaciones Forestales y Agropecuarias, obtained two varieties, 'Hector' and 'Esperanza' by irradiation of seeds from variety 'Suaqui 86' at 150 Gy. These new varieties exhibit an increased yield and reduction in dehiscence and lodging, being tolerant to white fly. 'SalCer' is another new soybean variety obtained by CESAEGRO through irradiation of seeds from line ISAEGBM2 at 200 Gy. Its improved traits are higher yields and increased height to first pod. Currently, in various institutions, several crops are under improvement through mutation breeding, such as Mexican lemon, aiming to increase fruit size and to reduce number of seeds; mango, trying to improve fruit quality and uniform maturity; avocado, looking for reduced height of trees, and agave, trying to select individuals tolerant to stem soft rot. Regarding to ornamental species, several studies are in process to induce variability on genus Dahlia, Euphorbia, Tigridia, Sprekelia and Ficus. Also a model has been developed to induce variability on endangered species by mutation and biotechnological tools. For example Mammilaria sanangelensis, has been rescued and variation has been induced through irradiation and in vitro culture. To provide alternative crops for peasants inhabiting marginal areas, a mutation breeding program at ININ allowed to select low saponin mutants of quinua by irradiation of seeds from cultivar Barandales at 200 and 250 Gy. Also focus has been placed on improvement of ancient crops, such as 'Huauzontle' and 'Chia roja' (Chenopodium berlandieri ssp. nuttalliae), amaranth and beans. Evaluation of putative mutants of these crops is currently underway. (author)