S03 - Session P1 - Guidelines for the caper seeds collection and selection for commercial use

Authors: María Laura Foschi *, Mariano Juan, Bernardo Pascual

The fruits of the caper ( Capparis spinosa L.) have many seeds, but these shown a low germination (G), especially in commercial lots. Although G up to 95% have been obtained with GA 3 addition in own-produced seeds, it has not exceeded 6% in commercial lots, probably due to the different collection and selection criteria. The mature own-produced seeds were selected by decantation, presenting all of them a dark brown color (DB). However, in commercial lots it is common to find also premature (brown; B) and immature (strong brown; SB) seeds. This study analyzes the germination of seeds extracted from different stages of apparently mature fruits [prior 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 maturation stages based on the coat color (DB, B and SB). The percentage of seeds floating in the decantation 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. All the seeds of type IV fruits floated, being 95% mature (DB). The viability of the seeds that floated was not affected by the type of fruit, but it was affected by its maturation stage (from 3% for SB to 24% for DB). The G was affected by type of fruit and maturation stage and by their interaction, so that the maximum G (22%) was obtained with DB seeds extracted from type IV fruits. The low G obtained in the floating seeds leads us to recommend collecting the ripe fruits before or immediately after dehiscence, since they presented the highest proportion (91-93%) of seeds that precipitate in the settling test, considered mature and of good quality. (G≈95%).