Flower bud on Nagami × Procimequat seedling

[Marcin]

This is a hybrid seedling of Nagami kumquat pollinated by Procimequat. It's a bit over 2 years old now and will be flowering soon. What's interesting is that the flower bud appeared on a low node.

[till]

Super. It will be triploid, will it?

[Marcin]

Till, it's hard to tell. I guess it's diploid, because its leaves and twigs are not very thick. Some other seedlings from this combination have thicker leaves and twigs, and might be polyploid.

[ilya11]

Congratulations! Its probably a common feature for kumquat hybrids to have first flowers on lower branches. At least Thomasville seedlings are also doing this.

[Marcin]

Thanks Ilya.
The flower opened today, it seems it has a developed pistil. So I hope there will be a fruit.

[mikkel]

Congrats Marcin! This is very interesting.

[Marcin]

Thanks Mikkel.
There is a chance for fruit. I moved the plant inside to protect it from slugs.

[mikkel]

Hello Marcin, are there any news about this hybrid?

[Marcin]

Hi Mikkel. The seedling you are asking about has fruited grafted on Swingle rootstock. I called it Progami 1. Two more seedlings of the same origin flowered last season and fruited on own root (Progami 2 and 3). This is their comparison.

Progami 1 - slow growing on own root, vigorous when grafted. Moderate flowering but fruit set is poor. The fruit is oval, smooth. The taste is bitter, and aroma resembles a green carrot (or simply, a procimequat) - not edible. Ripening time approx. 5.5 - 6 months. Seedy, appears monoembryonic. It was one of the hardiest out of ~40 seedlings in an early test.

Progami 2 - this one has been growing well on own root. Small flowers are produced abundantly during summer, and fruit set is very good. The fruit is slightly longer than broad, golden-orange to orange in color when ripe. It is sour-sweet, the aroma is orange or kumquat-like at first, then some aftertastes are detected. I find the taste better than of no. 1 and 3, but still I can eat only a few at once and don't feel like eating more. Ripening time approx. 4.5 - 5 months. Some fruits have no seeds, some have one or more. 100% monoembryonic and produces variable seedlings.

Progami 3 - mediocre growing on own root. Fruiting is not as rich as of no.2. The fruit is orange in color, more diverse in size compared to no. 1 and 2., often with a depression at the end. It is bitter-sweet-sour, the aroma is pungent, peppery. The strong bitterness makes it inedible. Ripened very fast, in approx. 4 - 4.5 months (about 2 weeks earlier than no. 2 and 4+ weeks earlier than no. 1). Many of the seeds are undeveloped, which makes it difficult to find a sufficient amount to plant. Appears monoembryonic.

Note. The ripening time was measured on the basis of fruit coloration in room temp. (min. 13 C, max. 22 C), under led lamps. After moving the plants to a cooler room with little light, the fruit coloration slowed down significantly.

[Marcin]

I find Progami 2 the most suitable for further breeding. With cross-pollination but also probably self-pollination it has produced a few dozens of seedlings, mostly healthy and with a good degree of variability.

In the photo all but one seedlings are from Progami 2.

[jibro]

Interesting that even complex hybrids with Hong Kong kumquat C. hindsii still have a short juvenile period, according to this study C. hindsii has the shortest juvenile period of all citrus, only 8 months...

www.researchgate.net/publication/332545703_Genome_sequencing_and_CRISPR_Cas9_gene_editing_of_an_early_flowering_Mini-Citrus_Fortunella_hindsii

[Marcin]

I hope among the seedlings there will be some flowering even faster than the Progami, still possessing the zygotic embryony trait and maybe also with improved fruit quality.
By the way, it is interesting that while the Procimequat I used in breeding is highly nucellar and polyembryonic, I haven't noticed any polyembryonic seed in any of the three Progami selections.