Effects of Different Embryo Development Stages and GA3 Doses on Germination in Clementine Mandarin × Carrizo Citrange Immature Embryos

Abstract

Citrus rootstock breeding is important to improve their resistance to diseases, pests and adverse environmental conditions. The majority of citrus species have nuceller embryony. Although Clementine mandarin is monoembryonic, in some cases (intercrossing etc.) abortive seed formation can be seen frequently. In this study, Clementine mandarin × Carrizo citrange were crossed. In the study, interspecies hybridization (Citrus × Poncirus) was used. Embryo rescue technique was used to prevent the loss of hybrid individuals due to abortive seed formation. The seeds were gathered from the crossed plants 80, 100, and 120 days after pollination. The immature embryos were removed from the seeds and these embryos were transferred to control, 0.5, and 1.0 mg l-1 GA3 containing medium to germination. The highest germination rate with 100% was observed from 1.0 mg l-1 GA3 containing media harvested 120 days after pollination. Additionally, the highest rate of trifoliate seedlings was obtained from embryos gathered after 120 days of the pollination.