Abstract

DARLAN RAMOS, José et al. Stigma receptivity and in vitro citrus pollen grains germination protocol  adjustment. INCI [online]. 2008, vol.33, n.1, pp.51-55. ISSN 0378-1844.

Data about the viability and germination of pollen grains are essential for the success of on-field controlled hybridizing. The purpose of this work was to study the stigmas receptivity period of citrus flowers under different stages and adjust the protocol to the in vitro pollen grain germination. Six essays were carried out with the aim to define the stages for collection and pollinizations, and to establish the pH and ideal sucrose, agar, calcium and boron concentrations, and temperature, for germination. For the Pêra, Natal and Valência sweet orange varieties, manual pollinization can be performed using flowers at the "balloon" stage. For the pollen grains germination of the Natal, Pêra and Valência varieties, the medium should be made of 100g·l^-1 sucrose, 800mg·l^-1 calcium, 200mg·l^-1 boric acid and pH= 6.5, exception made of the Pêra variety, whose germination was better at pH 5.0. A temperature of 25ºC provided the best percentage of germinated pollen grains for all varieties.

Keywords : Citrus ; Meio de Cultura ; Palinologia ; Reagentes .