Influence of Gamma Irradiation on Seedless Citrus Production: Pollen Germination and Fruit Quality

Gamma irradiation is widely used to obtain seedless citrus fruits. Herein, different new clones obtained by bud irradiation of several seedy citrus cultivars grown in the Mediterranean were studied to assess seedlessness, pollen germination, fruit characteristics and quality attributes. Findings indicate that irradiation altered aspects other than seedlessness, such as pollen germination, and some of the clones presented fruits with different weight, size, acidity and maturity index. Fruit quality and nutritional bio-components also were affected. Our results indicated high contents in natural antioxidants as vitamin C and phenolic compounds in these citrus varieties, and provide a qualitative and quantitative survey of the fruit taste and organoleptic quality. High-performance liquid chromatographic methods were used to identify and quantify these bioactive compounds. These aspects are important for the consumer that demands the prevention of health problems through nutrition and certain fruit quality traits, including fruit size, internal quality, good rind colour and easy peeling. All irradiated clones studied presented lower seed numbers and reduced pollen germination compared to the corresponding controls, and some of these clones, which ripen late in the season and whose fruit quality is maintained or improved, are in the process of protection. In conclusion, budwood irradiation is a suitable technique to improve cultivars, produce seedless cultivars, adjust ripening time or raise the content of health-promoting compounds.