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Wheat “blends” out-perform monocultures

This is astonishing. Luigi said that a dominant meta-narrative in our circles is that selection and breeding displace diversity. Another is that well-bred monocultures improve yields. There’s always been an opposing point of view, most closely associated with the name of Professor Martin Wolfe. Now no less a leviathan than the United States Department of Agriculture seems to agree.

In a ground-breaking experiment, USDA scientist Christina Cowger made mixtures — blends — of two or more wheat varieties and planted them in experimental plots in North Carolina. The results?

The blends outyielded the pure varieties by an average of 2.3 bushels per acre. … That’s a 3.2-percent yield advantage. Blends and pure varieties did not differ in test weight or quality across environments, and blends were either beneficial or neutral with respect to diseases.

Blends are also more stable from year to year, a fact that may be behind farmers taking matters into their own hands: 10 to 15 per cent of the wheat area of Kansas and Washington states was planted to mixtures over the past four years.

I’m looking forward to seeing the full published paper.

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Separating the cows from the goats

Some lactose intolerant people drink goat’s milk instead of cow’s milk because it is more digestible. Turns out they could be at risk of vitamin A deficiency. Well, not really. But a recent French study that compared farmhouse cheeses made from cow’s milk and goat’s milk discovered that chevres contained no beta carotene, a precursor of vitamin A. Vive la difference.

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Undoing millennia of barley selection

Generations of beer-loving farmers have bred seed dormancy almost entirely out of barley, so that the grains will readily germinate in the malthouse. Unfortunately, that means that malting varieties are sometimes prone to jumping the gun and sprouting before harvest, while the crop is still standing in the field. That means that the grain cannot be used to make beer. Not a good thing.

Fortunately, a PhD student in Australia, a land well known for its love of the amber nectar, has compared the barley genome with that of Arabidopsis and identified some bits which may contain previously unknown dormancy genes. Should a negative effect on pre-harvest sprouting be confirmed in the field – and trials are under way – breeders could use markers for these genes to help them select genotypes which will only sprout where it would do the most good: in the maltings.

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Durum wheat erosion

If there’s a dominant meta-narrative in agricultural biodiversity circles it is that modern breeding programmes relentlessly decrease the genetic diversity of crops, increasing yields and quality but also, as new varieties displace landraces and older varieties in farmers’ fields, depleting the very resource on which they are dependent for continued success. But actually there’s not really that much in the way of hard figures on this process. So a recent paper on what breeding has done to diversity in Italian durum wheat is very much to be welcomed.

The researchers used molecular and biochemical markers to compare genetic diversity among five different groups of durum varieties, ranging from landraces from before 1915, to pure lines derived from landraces in the 30s, to genotypes selected from crosses between local material and CIMMYT lines in the 70s. In general, there was indeed a narrowing of the genetic diversity within these groups over time. In fact, the degree of narrowing was probably underestimated, because only a relatively few of the pre-1915 landraces were still available for analysis. Conserving what is left is all the more important.

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Alternative livelihoods

Do wander over to the latest edition of New Agriculturist, which, among other things, has a great feature giving examples of farmers adopting new crops and other ways of making a living as alternatives to illicit, environmentally damaging or otherwise inappropriate ones.