Reproductive biology of Habranthus tubispathus

Abstract

Habranthus tubispathus is a bulbous species native to the sub humid and semiarid Pampean regions of Argentina, with a high aesthetic ornamental value for sustainable landscaping. In order to initiate breeding programs, the reproductive biology of the species was investigated. Self- and cross-pollinations were done on plants collected from a natural population. Fruits set were recorded in both self- and cross-pollinated plants, as well as in open-pollinated plants from the natural population. The fructification ratio, the reproductive success (RS) and the compatibility index were obtained. Also, observations of pollen tube growth in pistils of both types of pollination were evaluated. Self- and cross-pollinated plants set fruits. The fruit setting was lower in self-pollinated plants (59.4%) as compared to cross-pollinated ones (91%), which showed similar setting as open-pollinated plants (93%). Accordingly, RS values were 0.26 and 0.37 for self-pollinated and cross-pollinated plants, respectively. The growth of the pollen tubes (more than 100 tubes reaching the ovary) and the quantity of seeds per fruit (53) did not differ among self and cross-pollinated plants. Another evidence of H. tubispathus outbreeding is the presence of herkogamy in flowers, despite that this species exhibits partially self-compatible with the compatibility index value of 0.65.