Eduardo Cesar Brugnara

TESTE DE PATERNIDADE E AVALIAÇÕES AGRONÔMICAS DE POSSÍVEIS HÍBRIDOS DE TANGERINEIRA 'SUNKI'

Citrus production is spread all over the world. In Brazil citrus represent the major volume of fruit production. The rootstock is extremely important to establish a good-quality orchard. At the Estacao Experimental Agronomica of the Universidade Federal do Rio Grande do Sul was established placed a hybrid citrus plants orchard, originated from openpollination with ‘Lee’ tangelo [Citrus clementina Hort. ex Tan. x (C. tangerina Hort. ex Tan. x C. paradisi Macf.)] as female parent. Amongst those hybrids, fourteen plants were selected with characteristics alike to those of the rootstock ‘Sunki’ tangerine (Citrus sunki Hort. ex. Tan.) In order to confirm hybrids paternity, single sequence repeat (SSR) markers were used. The molecular analysis allowed to identify eleven hybrids that did not have ‘Sunki’ tangerine as male parent. The hybrids 49, 77 and 92, potencialy hybrids of ‘Sunki’, stood out for higher poliembriony, higher number of emerged seedling per seed and higher number of seeds per fruit in comparison to ‘Sunki’.

Ploidia e fertilidade de pólen em progênies de citros

PLOIDY AND POLLEN FERTILITY IN CITRUS HYBRIDS This work was performed to estimate pollen fertility and determinate the ploidy level of 11 to 12 years old progenies of crosses of ‘Montenegrina ’ mandarin (Citrus deliciosa Ten.) with ‘King’ mandarin (C. nobilis Lour.) and with ‘Caipira’ sweet orange (C. sinensis (L.) Osb.) maintained at Estacao Experimental Agronomica of UFRGS, in Eldorado do Sul, Brazil. The ploidy level was determined by chromosome countings in meiosis cells and pollen fertility evaluated by staining pollen grains with propionic carmine. All evaluated hybrids are diploid and pollen fertility varied from zero to 98%. C27, a hybrid ‘Montenegrina’ x ‘Caipira’, was found is sterile, and C21, from the same cross, showed 10 % fertility. The lowest observed fertility in the progeny ‘Montenegrina’ x ‘King’ was 42 %.