Cassava as you’ve never seen it

22 February, 2013 by (comments)

When I heard that CIAT cassava breeder Hernan Ceballos had some “very strange” cassava to show us, I didn’t waste any time in calling to clarify what he meant. He gave little away: “you have to see it.”

Very soon we were in one of CIAT’s vast fields of experimental cassava. I wondered what exactly we’d find: cassava roots with mildly amusing shapes? Multicoloured roots, perhaps? But Hernan wasn’t carrying a harvesting tool; it was the plants themselves that would be strange.

As we walked I hoped I’d be able to oblige Hernan’s conspiratorial charm by instantly recognising what it was about the plants that was strange. Hopefully it would be obvious to the cassava novice and not some hard-to-photograph quirk premised on a scientific technicality.

Hernan Tryptich_lo3

I wasn’t disappointed. Anyone who’s seen a “normal” field of cassava knows that the plants grow a few feet high, a few feet wide, are bushy – perhaps even a bit spindly – with finger-like leaves extending in all directions from the trunk, on the end of slim stalks – or petioles. A whole field of cassava is normally impenetrably dense. After passing trials of what I considered normal-looking cassava, one plot stood out immediately.

Rather than bushy, these were soaring columns of cassava – sturdy, compact, and standing nearly ten feet-high, the leaves growing straight out from the trunk with no petioles whatsoever. For want of a better analogy, they reminded me of Marge Simpson’s towering beehive hair-do, in a rich, racing green. According to Hernan, the CIAT researchers refer to the plants as “Asparagus Cassava.” They weren’t just strange; they were the strangest cassava plants I’d ever seen.

Hernan himself was clearly quite excited. Using cuttings maintained at CIAT’s gene bank, the centre’s cassava scientists had inbred the plants to see what kinds of hidden traits they would express – characteristics that normally lie dormant in their DNA.

The resulting tall, slim plants mean you can quadruple the number of plants per plot, Hernan told us. Assuming the yield per plant of Asparagus Cassava planted at high densities is comparable to conventional varieties at normal densities, you could be looking at a big boost in yields. That would be a boon for smallholders growing cassava for food, he continued, those supplying the ever-growing industrial demand for cassava starch, and due to increased production on the same area of land, would help reduce the workload of women producers in Africa.

The fact that Asparagus Cassava can be planted in neat rows, easily accessible and navigable by farmers also means they could be harvested mechanically, said Hernan. While machine harvesting is not suited to some parts of the cassava-producing world, industrial producers will surely take note.

An additional benefit is for livestock: mechanical harvesting of the Asparagus Cassava leaves – free of the fibrous petioles – would be much easier, and the resulting feed of higher quality.

Hernan is not the kind of scientist to use the phrase “green revolution” lightly in relation to his own research. But during our half-hour excursion to see the “strange” cassava, it kept popping up in relation to the crop’s potential. He told us that with Asparagus Cassava, the CIAT team would like to replicate the success of maize scientists, who increased the crop’s tolerance to “crowding”, enabling planting densities to increase three-fold with major gains in yields.

Few would dispute that a tripling of cassava yields would very likely signify the revolution the crop has been waiting for for so long. When high-density Asparagus Cassava trials begin in May 2013, Hernan will be able to put his hypothesis to the test.

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