Category: Threats

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Another crop wild relative to the rescue

I’ve just run across a new paper which, apart from being interesting, also gives me the opportunity to apologize for nibbling earlier today an item on Fusarium head blight (FHB) that Jeremy had already discussed at some length about a month ago! The original item had to do with the sequencing of the genome of the fungus which causes FHB, a serious disease of wheat and barley. Two strains were in fact compared, and Jeremy blogged about the differences that were found in the two sequences. He ended his ruminations thus:

You may remember that a joint team of Israeli and US researchers recently reported that a wild relative of wheat, Sharon Goatgrass (Aegilops sharonensis), is loaded with resistance genes that protect it against seven of the most important fungal diseases of wheat. Alas, none of the samples tested was resistant to Fusarium head blight. How about some other wild relative species, though? We shall see.

Well, the Molecular Breeding paper I’ve just been alerted to should make him happy. In it, Xiaorong Shen and Herbert Ohm at Purdue report that they found resistance to FHB in bread wheat lines into which had been introgressed bits of a chromosome of a wild relative, Tall Wheatgrass, or Thinopyrum ponticum. The bits of chromosomes were from different sources, and their introgression into wheat caused different reactions to FHB infection, showing that there’s variation in resistance to the pathogen as well as within the pathogen itself.

GRIN has records for two accessions under this name, both from the Vavilov Institute in Russia, but suggests that name is actually a synonym for Elytrigia pontica, for which there are a total of 18 accessions in the USDA system (another synonym is Triticum ponticum). SINGER has records for two accessions of Elytrigia, but none for the species in question, under none of these synonyms. EURISCO has only one record. Looks as though some more collecting may be in order. The distribution of the species seems to be central and southern Europe, the Caucasus and western Asia.

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Uses for giant earthworms

A comment on the threat to the Banaue rice terraces prompted me to go Googling, and it seems the story has legs. Unlike the giant earthworms, which may or may not be an all-female species related to a worm called Polypheretima elongata. SciDev.net reports on the efforts of an Indian scientist, Ravindra Joshi, to help the villagers to get rid of the giant earthworms and the rats ((There’s a less informative and slightly garbled version in The Daily Telegraph.)).

To tackle the earthworms, Joshi’s team taught the Ifugao a method of ‘worm farming’ that is popular with small-scale entrepreneurs in the lowlands. The Ifugao collect the worms and rear them in a mixture of soil and old newspapers. They then harvest the worms and process them into feeds used by fish farmers.

Elsewhere in the Philippines people eat worm sausages and burgers, but the Ifugao people who built Banaue have a taboo against soil dwelling creatures. There wasn’t such a taboo against eating rats, so Joshi worked with the locals to develop a community system of rice traps that uses a particularly aromatic rice planted early as a trap crop to lure the rats to their death.

There’s another rodent, though, that eats the giant earthworms. So the villagers have learned to distinguish Rattus tanezumi from Chrotomys whiteheadi, eating the former but releasing the latter to eat the giant earthworms.

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Animal diseases reviewed

Thanks to Danny Hunter for pointing to two recent posts at CABI’s blog, one on bovine spongiform encephalopathy (mad cow disease to you and me), the other on bluetongue disease. BSE seems to be running its course and to be more or less under control, even though many mysteries still surround it. Bluetongue, however, is altogether more menacing, because it seems to have reached Britain at least partly as a result of climate change, which has allowed the midges that spread the virus to expand their range. This could be the start of something big. I don’t believe there is any resistance associated with different breeds of cattle, but I could be wrong.