About the variety
Citrangequat ‘4 seasons’ comes originally from the USA, and is known there as citrangequat ’10-3-4′, or “Citrangequat Hybrid US 10-3-4”. It’s not clear whether it’s a true citrangequat (citrange-kumquat hybrid), or a citrangequat crossed with some other citrus.
Its growth is very much dwarfed, and the plant has a strong tendency to flower many times a year – hence its name “four seasons”. Sometimes it will not grow at all, but will bloom all the time. The flowers often appear in clusters. They are pleasantly scented, with long petals, which can sometimes be very narrow. The leaves on a mature plant are entirely unifoliolate, and the twigs are almost thornless – Poncirus parentage is not obvious at the first sight. It can be guessed most easily from the fuzzy character of fruitlets (inherited from Poncirus). The fuzziness however disappears as the fruits grow bigger.
Since much of the Poncirus genes seem to have been lost in this hybrid, it can’t be expected to be very hardy. From the limited information available, it seems to be less frost resistant than ‘Thomasville’ citrangequat. I grow it in pots – in my zone 6 climate it wouldn’t survive the winter without protection.
Citrangequat ‘4 seasons’ fruitlets are fuzzy – the trait inherited from Poncirus.
Fruit
The fruit of this hybrid is unexpectedly big for the dwarf plant it grows on. In Spain the variety may be also found under the name Limón Pera – “lemon pear” – and this seem to describe the fruit well. The fruit indeed is pear-shaped, and can be used in a similar way to lemon.
But it’s not a typical lemon. The fruit is aromatic, before being cut it smells of grapefruit. After cutting, additional pine and lemon aromas are revealed. The flesh is soft and juicy. It has a pleasant aroma most similar to pummelo, tastes sour (less sour than lemon) with some sweetness and bitterness. No sticky resin. The bitterness is more in the membranes than in flesh, and is not very strong. The peel is very bitter though. The fruit contains many seeds, at least when cross-pollinated. They appear monoembryonic and zygotic – a trait good for breeding.
The drawback is that getting a ripe fruit from citrangequat ‘4 seasons’ is not easy on a small plant. It seems easier when it is grafted on a bigger rootstock. Another factor favoring fruit set may be cross-pollination.
My original small plant refused to hold fruits to maturity, but when I grafted this citrangequat to a bigger Flying dragon rootstock, and cross-pollinated the flowers, the fruit set successfully.
Another note: this seems to be a rather late ripening variety – I harvested the fruit approximately 10 months after flowering.
Potential uses
Edible fruit
Having a pleasant aroma and being devoid of the sticky resin often found in hybrids with Poncirus genes, this fruit is definitely edible. Too soft to be eaten with a spoon, it can be best used for juice or lemonade. Because it’s less sour than a lemon, the juice is drinkable even without sweetening (but may be still too sharp in taste – perhaps better to add some sugar). After dilluting with water and sweetening, it makes a good lemonade-type drink.
Ornamental
Apart from the culinary uses, ‘4 seasons’ citrangequat makes a good ornamental plant for pot culture. It will flower most of the growing season (the most abundantly in summer – trait inherited from kumquat). The fruits won’t appear always (often all the flowers will drop), but when a fruit is set, it will add to the plant’s ornamental value. As four seasons citrangequat plant grows very slowly, it will likely remain compact-sized for many years.
Breeding
If one wants to breed primarily for frost hardiness, ‘4 seasons’ citrangequat wouldn’t be his first choice. But this variety has another traits potentially useful in breeding: dwarf growth habit with abundant flowering, and big, edible fruit. Zygotic seeds are beneficial, and it also produces huge quantities of pollen. Additionally, its hybrids could be hoped to flower faster from seed – although this hasn’t been confirmed yet.
4 seasons citrangequat still has some genes from Poncirus. The influence of Poncirus is sometimes more visible in its hybrids than in the citrangequat itself. For instance, while ‘4 seasons’ is entirely unifoliolate as a mature plant, some of its hybrid seedlings will occassionally produce a bi- or trifoliolate leaf. I think getting progeny with improved hardiness isn’t impossible.
Summary
While many of the existing Poncirus hybrids are planted primarily for the improved frost hardiness, but at the same time have drawbacks such as not fully edible fruit, high thorniness, etc. – in my opininon, 4 seasons citrangequat is a different type of plant. It could compete with “true” citrus in its ornamental and edible qualities. However, this is not a typical fruit variety. Because of its dwarfness, it would be best suited for pot culture. Additionally, it may be used in breeding projects, both as a seed and as a pollen parent.