What Is A Persistent Caprifig?

In a simple nutshell: Persistent caprifigs have a valued genetic quality to potentially produce common fig type offspring. But for those who wish to dive deeper…

According to W.B. Storey (1975), there is a dominant mutant allele (P) for persistent syconia and ovule abortion. This allele is egg lethal so it can only be carried in the sperm. In other words, it cannot be passed on from a persistent female tree. The homozygous genotype PP is not possible. A recessive wild type allele (+) results in caducous syconia and normal ovule development. It can be carried by the egg and sperm. Therefore the only possible genotypes for caprifigs and female trees are P+ and ++. Persistent caprifigs and persistent female trees must be heterozygous (P+). Mature pollinated syconia on heterozygous female trees having the allele for persistence (P) may contain hollow drupelets (cenocarps) as well as normal seed-bearing druplets. Although I don’t have a specific reference, I don’t see why the persistent allele (P) could not occur in wild populations of F. carica. This allele does not appear advantageous to the female fig, although if wasp-bearing caprifigs are nearby the syconia are capable of producing seeds.

This is a complicated subject when discussing the biology of Ficus carica. In general, unpollinated parthenocarpic cultivars with the persistent gene must be propagated by cuttings because the druplets in their syconia are hollow cenocarps without seeds. These cultivars have been grown and selected for flavorful “figs” and, like many other excellent fruit cultivars, must be propagated asexually in order to obtain clones. Cultivars such as the ‘Verte’ are valuable because they are absolutely delicious and do not require wasp pollination in order to set fruit. If these parthenocarpic cultivars are pollinated by a nearby caprifig they can produce seed-bearing druplets in addition to hollow druplets (cenocarps). The remains of female F. carica syconia have been discovered in archaeological sites of the Jordon Valley that date back 11,400 years. They are clearly persistent, parthenocarpic syconia containing hollow druplets (cenocarps). When M.E. Kislev concluded they were planted by cuttings and possibly represented the first known domesticated plants, perhaps he assumed that the trait for persistent syconia was unique to seedless fig cultivars. According to Storey (1975), this gene can occur in both female trees and caprifigs. It is passed to female progeny in the sperm of caprifig pollen parents. Female parthenocarpic trees with the persistent gene can produce seeds if they are pollinated by fig wasps. The ancient syconia of the Jordon Valley with hollow cenocarps could have come from unpollinated female trees that grew from seeds.

Ficus carica With Persistent vs. Caducous (Early Deciduous) Syconia

For more detailed information on caprifigs, see Caprifigs and Caprification by Ira J. Condit.