About my discovery of spontaneous crosses, with orange pollen, between Ocimum basilicum and Ocimum kilimandscharicum

These are clearly natural hybrids involving Ocimum basilicum and Ocimum kilimandscharicum.

Why not involving Ocimum bisabolenum? Because there is no testimony about the possibility of interspecific crosses, with the temperate Tulsi from Ethiopia , in 40 years of professional organic seed production… but there are with Ocimum kilimandscharicum.

The first conclusion to be drawn from this is to avoid cultivating these two species simultaneously for pure seed production.

The second conclusion is that such crosses, if fertile, can confer to Ocimum basilicum cultivars greater resistance to cold – and perhaps even greater resistance to basil blight.

Flowers from a spontaneous cross – a natural hybrid – between Ocimum basilicum and Ocimum kilimandscharicum. Photo by Xochi.

Xochi. September 26th 2024

Contact: Xochipelli@protonmail.com

This year, 2024, I didn’t sow any Basils and simply moved, or transplanted into large pots, the seedlings that volunteered during the summer in the garden. These seedlings come from seeds produced from 30 varieties, or species, of Ocimum – which self-seeded in 2022 or were broadcasted in the spring of 2024.

Thus, this year, I replanted around 50 seedlings of Ocimum bisabolenum, 1 seedling of Ocimum americanum var. americanum “Malawi Camphor”, 2 seedlings of Ocimum kilimandscharicum and, finally, 3 seedlings of Ocimum basilicum – or presumed to be.

Some forty Ocimum bisabolenum seedlings were replanted during the last days of August.

Regarding the 3 Ocimum basilicum seedlings or presumed to be. The first gave a magnificent “Fino Verde” Basil plant.

Plant, with orange pollen, from a spontaneous cross – a natural hybrid – between Ocimum basilicum and Ocimum kilimandscharicum. Photo by Xochi.
Ocimum basilicum. Photo by Xochi

As for the other two, they surprised me by expressing themselves with orange pollen… whereas the color of Ocimum basilicum pollen is, strictly speaking, white – at least, there’s no reference on the Web to the contrary.

As a reminder. Only intra-specific crosses are prevalent in the Ocimum genus. Spontaneous interspecific crosses are extremely rare.

Ocimum kilimandscharicum. Photo by Xochi

Clearly, in my garden, these are two manifestations of natural hybrids involving Ocimum basilicum and Ocimum kilimandscharicum. Indeed, this would not be the first case – not to mention sterile cultivars such as “African Blue”, “Magic Mountain F1” and “Magic White F1” – since the Lucknow agronomy center, in India, has developed new, cold-resistant lines from natural hybrids involving these two species, growing in their gardens around 2010.

Source: “Generation of novelties in the genus Ocimum as a result of natural hybridization: A morphological, genetical and chemical appraisal”.

In my garden, the first natural hybrid, in the ground, is a large plant – which I’m going to try to replant… because it grew right in the middle of a very packed driveway covered with olive bark. As for the second, it’s in a pot.

Flower morphology. In the first hybrid, in the open ground, the corolla core, style and stamens are purplish. Style and stamen length are between those of Ocimum kilimandscharicum and Ocimum basilicum.

In the second hybrid, in pots, the corolla is relatively white, with a slight mauve tinge. The pistil is purple, but the stamens are white. Style and stamen length are more in line with those of Ocimum kilimandscharicum.