How to prepare Inga seeds for sowing

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Inga seeds come in several colours, the ones shown above are all from the same pod and more or less at the same stage of development

We are planning to trial three or four native species of Inga, the most common of which is the domesticated Inga edulis. Because we want to develop the approach in a way that can be easily be replicated by our partner communities we source seed locally. Inga seeds are known as recalcitrant seeds, that is they have no dormant stage as most seeds do and so cannot be stored for any length of time. So the seeds strategy is to hit the ground running and  it is not uncommon for the seeds to germinate in the pod. It also means that we need to sow the seeds within 48 hours of harvesting them. We start by  collecting fruits, shelling the pods and removing the sugary white aril.

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Members of the Pimpollo community shelling Inga pods. We had over 300 pods containing ca 4000 seeds to shell. It is not as unpleasant task as it may seem as each seed is surrounded by a delicious sweet spongy flesh that kids and adults alike love

Because we are using Inga, in part to harness it’s soil-fertilizing Rhizobium bacteria, we need to make sure that the germinating roots encounter them. To do so we collect nodule-bearing roots from local Inga trees and grind them up in a mixture of water with some soil in a large basin. Then we place the freshly shelled seeds to soak in this overnight. The idea is that the bacteria escape the ruptured nodules and infect the seeds.

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Inga seeds are inoculated by soaking them overnight in macerated Inga roots mixed with water, here a villager from Motacusal is macerating the roots

The seeds themselves vary a lot in size, shape and colour. They are shaped to sit vertically in the soil and the base of the seed has four anchoring projections that keep it upright and protect the emerging roots. The seeds need to be sown vertically, the base down and with the top of the seed sticking out by a few mm from the surface. Once sown we sprinkle a layer of soil over them and water them well. Because the seeds have no dormant stage germination is instant and after just two weeks the seedlings are 10-15 cm tall.

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Once inoculated the Inga seeds are planted in plant-bags, they germinate immediately and should be about 30 cm high within two months

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