CONICET | Buscador de Institutos y Recursos Humanos

Habranthus tubispathus is a geophyte species native from the subhumid and semiarid Pampeana region (Argentina) with a high aesthetic ornamental value for sustainable landscaping. In order to initiate breeding studies, the reproductive biology of the species was investigated. Self-pollination and crosses were done on H. tubispathus plants obtained from a natural population. The quantity of fruits set was recorded in both self and cross-pollinated plants, as well as in free pollinated plants from the natural population. The fructification ratio was calculated as % Fructification= (fruits set/pollinated flowers) x 100. The reproductive efficiency (%RE) was obtained according to the Dafni?s formula, % RE= (number fruits/ number pollinated flowers) x (average number of seeds per fruit/average number of ovules per ovary). The compatibility index (CI) was calculated as the percentage of set fruits by self-pollination/percentage of set fruits by cross-pollination. The species are classified according to the following CI ranking: 0 self-incompatible, 1 self-compatible, and >0 and <1 partially self-compatible. The growth of the pollen tubes in fixed pistils of both types of pollinations was also evaluated. Fruits were obtained in both, self-pollinated and cross-pollinated plants. The fructification ratio was lower in self-pollinated plants (59.4%) compared with cross-pollinated ones (91%), hence with a similar fructification ratio showed by natural pollinated plants (93%). Consistent with this, REs of 0.37 and 0.26 for the cross-pollinated and self-pollinated plants, respectively, were obtained. Nevertheless, the growth of the pollen tubes (more than 100 tubes that reaches the ovary) and the quantity of seeds per fruit (53) were not different in both cases. Another evidence in favor of the preference for the cross pollination of H. tubispathus is the presence of herkogamy approach in flowers, despite the compatibility index was 0.65.

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