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Estimation of the Degree of Self-incompatibility Reaction during Flower Bud Development and Production of Self-fertilized Seeds by Bud Pollination in Self-incompatible Citrus Cultivars

2004; Kyushu University; Volume: 49; Issue: 2 Linguagem: Inglês

10.5109/4591

2433-488X

Akira Wakana, Binh Xuan Ngo, Isao Fukudome, Kohei Kejiwara,

Greenhouse Technology and Climate Control

Bud pollination in seven self-incompatible Citrus cultivars was carried out to produce self-fertilized seedlings with genotypes homozygous for the self-incompatibility gene.Flower buds of the seven self-incompatible Citrus cultivars, 'Banpeiyu' (C.graudis) , 'Hirado Buntan' (C.graudis), 'Hassaku' (C.hassaku), 'Shishiyuzu' (C.pseudogulgul), 'Clementine' (C.clementina), 'Tosa Buntan' (C.otachiba?ea)and 'Hyuganatsu' (C.tamurawa), were emasculated at various stages of flower bud development, and self-pollinated with their fresh pollen from flower buds collected just before anthesis.Seeded ftuits were obtained from flower buds of 6-8rnrn length for 'Clementine', 7-1 1 un for 'Hyuganatsu', 11-15rnrn for 'Shishiyuzu', 6-14rnm for 'Hassaku', 12-19rrun for 'Hirado Buntan' and 12-22 mrn for 'Banpeiyu'.The optimum length of flower buds for self-fertilized seed production was 6 mm for 'Clementine', 8-12 mm for 'Hassaku', 9-13 mm for 'Hyuganatsu', 1 1-14mm for 'Shishiyuzu', 12-17mm for 'Hirado' and 14-19mrn for 'Banpeiyu'.Flower buds producing the largest number of perfect seeds in each self-pollination were about half the length of those just before anthesis.At or just after this stage of flower bud development, stigmatic exudate production occurred.The largest nurnber of perfect seeds in self-pollinated fruits was almost the same as the average number of perfect seeds in open-or cross-pollinated ftuits in six cultivars except for 'Shishiyuzu' in which self-pollinated fruits contained a few seeds.These results suggested that half-sized flower buds in their development were the most optimum stage for the production of self-fertilized seeds by bud pollination in self-incompatible Citrus cultivars, and that self-incompatibility reaction increased after this stage.It was also suggested that in 'Shishiyuzu' the self-incompatibility reaction is different from that in the other six Citrus cultivars.No difference was found in size between self-fertilized and cross-fertilized seeds.The self-fertilized seeds gerntinated and grew normally without any inbreeding depression.