Obtaining citrus hybrids by in vitro culture of embryos from mature seeds and early identification of hybrid seedlings by allele-specific PCR

Two trifoliate oranges (Poncirus trifoliata var. monstrosa and P. trifoliata cv ‘Xiaoganzhi’) were used separately as pollinators to cross with Shantou-Suanju (Citrus sunki Hort. ex. Tan.) for breeding new citrus rootstocks. Embryos from the seeds of mature fruits were rescued and individually cultured in vitro. On average, 9.0–10.0 embryos per seed were harvested from the two crosses. The zygotic seedlings were only derived from large- to …