Development of Seedless Orange and Grapefruit Cultivars through Seed Irradiation

Abstract

Seed of ‘Pineapple’ orange [ Citrus sinensis (L.) Osbeck] and ‘Duncan’ and ‘Foster’ grapefruit ( C. paradisi Macf.) were exposed to gamma rays at 10, 15, 20, 25, and 30 krad. Seedling emergence was delayed. LD 50 levels were 10-15 krad for ‘Pineapple’, 15 krad for ‘Duncan’, and ≤10 krad for ‘Foster’. The greater sensitivity of ‘Foster’ may have been due in part to higher seed moisture content at treatment. Seedless mutants were obtained following gamma irradiation and fruiting of small numbers of seed and seedlings. The frequency of seedless mutants of ‘Pineapple’ and ‘Duncan’ was highest following treatments of 20-25 krad.