Criteria for the caper seeds collection and selection for commercial use

M.L. Foschi, M. Juan, B. Pascual, N. Pascual-Seva
The fruits of the caper (Capparis spinosa L.) have many seeds, but these shown a low germination percentage, especially in commercial batches. Although this research team has obtained germination percentages up to 95% in own-produced seeds, it has not exceeded 6% in commercial batches (both with GA3 addition), probably due to the different collection and selection criteria. In our prior studies, the mature own-produced seeds were selected by flotation, presenting all of them a dark brown color (DB). However, in commercial batches it is common to find also brown (B) and light brown (LB) seeds. This study analyzes the germination response of seeds extracted from different stages of apparently mature fruits (before dehiscence (type I), immediately after dehiscence (type II), 2-3 days after dehiscence (type III) and dried fruits collected up to 10 days after dehiscence (type IV)) and different seed coat color (DB, B and LB). The percentage of seeds floating in the flotation test increased with the delay in collection (from 7% of type II to 100% of type IV), since the seeds are dehydrated after the fruit dehiscence, decreasing its density. It is remarkable that 95% of type IV seeds were DB, although all of them floated. The viability of the seeds that floated was not affected by the type of fruit, but it was statically related to its coat color (from 3% for LB to 24% for DB). Germination was affected by type of fruit and seed coat color and by their interaction, so that the maximum germination (22%) was obtained with DB seeds extracted from type IV fruits. The low germination obtained in the floating seeds leads to recommend to collect the ripe fruits before or immediately after dehiscence, since they presented the highest proportion (91-93%) of seeds precipitating in flotation test, and they can be considered ripe and of good quality.
Foschi, M.L., Juan, M., Pascual, B. and Pascual-Seva, N. (2023). Criteria for the caper seeds collection and selection for commercial use. Acta Hortic. 1365, 65-72
DOI: 10.17660/ActaHortic.2023.1365.8
Capparis spinosa L., flotation method, seed coat color, seed viability, germination percentage

Acta Horticulturae