Obtaining spontaneous haploids and polyploids from seeds derived from tangerine-type fruits

Obtaining citrus polyploids, especially from triploid individuals, is of great importance for genetic improvement programs, as they produce seedless fruits. Therefore, the aim of this study was to use flow cytometry analyses to identify polyploid individuals among tangerine-type seedlings originating from seeds germinated in vitro. Fruits were collected from 13 different genotypes in the municipality of Mucugê (state of Bahia, Brazil). The seeds were then removed and classified as developed (seeds with well-formed integument), underdeveloped (seeds with wrinkled integument) and small (seeds of 1/3 to 1/6 of normal size). After the integument was removed, the seeds were disinfected and introduced into a WPM culture medium, in which they remained for 120 days. After this period, the percentage of germinated seeds and growth variables were evaluated, and ploidy analysis was conducted using flow cytometry. The developed seeds displayed a higher germination rate (91.5%) than the others. The small and underdeveloped seeds resulted in a considerable frequency of spontaneous polyploids (11%), and one haploid plant was also obtained from the latter class.