Scirpidiella's Plants: Hybrid of Hardy Tamarillo’s (Cyphomandra corymbiflora x fragrans)

From a few years I am growing 2 rare half-hardy tamarillo species: Hardy Tamarillo Cyphomandra corymbiflora and Guava Tamarillo C. fragrans = C. diploconos. I have already described the in 2 other posts in February and September 2018 yr. Last year I tried to cross both species to obtain a hybrid which has been described by prof. Lynn Bohs as easy to creating and fully fertile [Crossing Studies in Cyphomandra (Solanaceae) and Their Systematic and Evolutionary Significancs. American Journal of Botany,Vol. 78, No. 12 (Dec., 1991)].

Cyphomandra corymbiflora x fragrans (F1) - young seedling

Bellow I am going to describe my experiences with crossing (hand pollinating the flowers etc.) these 2 species and sowing their hybrid seeds (with photos). I can say that both species are self-incompatible and the flowers are naturally pollinated by bumblebees (at least in Europe), but with very small success in my experience (maybe due to small amount of these insects in my area). I ready that crossing female C. corymbiflora and male C. fragrans gives fertile seeds (and next healthy viable hybrids) but adverse combination (female C. fragrans and male C. cormbiflora) is not succeed.

Hand pollinating: I made a mistake and I first started to pollinating already opened flowers (which could be pollinated by bees before) but after first pollination I covered whole inflorescence in organza bag, so next fruits (which I pollinated later) was certain hybrid. Probability that any of these hand pollinated (crossing) fruits is not hybrid, is very low. I had very large success with hybrid hand pollination, because almost all (I estimate it for about 60-70%) pollinated flowers (C. corymbiflora x C. fragrans) developed info fruits (finally I harvested over 20 hybrid fruits). In comparison I harvested only a few (about 5) fruits from flowers pollinated by bumblebees (from 3 trees of C. corymbiflora) after whole long flowering season in 2018 yr. The hand pollinating was made in August (C. cormbiflora flowered from May/June, but C. fragrans created first flowers as late as in early August, so crossing was possible only in this time). I had much more success with hybrid pollination than pollination of C. corymbiflora by pollen of other C. corymbiflora (because it is very difficult to get pollen from flowers of C. corymbiflora, because it creates very little amount of it in its anthers, but the C. fragrans has flowers fully of pollen, so its preparing from them is much easier). I will show how I made pollination on the photos bellow. The fruits ripened about 4 months later, in November and December. In this time plants were stored (since September) in cool cellar in about 5-10C = 41-50F degree first (and next, in end of this period, even only about 2C = 35F degree). So fruits had not very good temperature to ripe well and they fall down half-ripe. Next I stored them in paper bag with ripe apples (which are emitting an ethylene) to they become overripe (within 2-3 weeks after dropping the fruits and harvest). I harvested numerous hybrid seeds but they were worse developed (something smaller) than clean C. corymbiflora and their germination rate was low (about 5%, maybe more). The seedlings are small yet, but they are growing healthy. I will make next update-post when they grow up. I am very curious of appearance of this hybrid. It is said to have intermediate features between its parents. Now there is visible that young seedlings have hairy leaves (similar as female parent – C. corymbiflora).

Cyphomandra fragrans - flowers (young ones are purple, older ones are yellowish)

Harvesting a pollen to hand pollination - 1 step

Harvesting a pollen to hand pollination - 2 step (removing anthers)

Harvesting a pollen to hand pollination - 3 step

Taking a pollen to brush

Hand pollination of flowers Cyphomandra corymbiflora by pollen of C. fragrans

Young fruits a few days after the pollination

Older fruits

A success of hand pollination was high

... in comparison to pollinating to bee pollinating (which was low succeed)

Fruits obtained after crossing pollination Cyphomandra corymbiflora x C. fragrans - just ofter harvesting (still green)

The fruits after overripening

There are visible well developed seeds (paler?) as well as degenerated ones (darker)

Overripe fruits (the fruits after crossing) were distinctly yellowish

The fruits of clean Cyphomandra corymbiflora after overripening (still clean green outside, not yellowish)

The seeds removed from fruits obtained after crossing pollination Cyphomandra corymbiflora x C. fragrans (viable -paler as well as degenerated -darker)

The young seedlings of hybrid of hardy tamarillo's Cyphomandra corymbiflora x fragrans (F1)

I harvested also a few fruits from C. fragrans tree. They were oppen pollinated (I am not sure if hybrid or apomictic – because it is self-incompatible species and I have only 1 tree). The fruits were green when they fall down on January 2019, and they have not became yellow after overrripening (as fruits which I obtained from Brazil a few years ago, which were clean yellow). The thick of fruits was very thick, strong and flesh was acid, but almost without aroma (cool cellar is not the best to ripening the fruits, I think). Inside were several dozen of seeds, but almost all were probably unviable (they have not fall down in water), only 5 seeds were probably viable. I am going to sow them.