Category: Breeding

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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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Bottlegourd to the rescue

Zucchini yellow mosaic virus (ZYMV) does not, alas, restrict itself to zucchini, or even courgettes. It attacks most cucurbits, including cucumbers, melons, pumpkins, squash, bottlegourds and watermelons. One of those, however, the bottlegourd Lagenaria siceraria may also hold the antidote to ZYMV. Scientists at the Agricultural Research Service of the USDA grew seeds of 190 different accessions from a USDA genebank and inoculated the seedlings with virus.

To their surprise, 36 accessions of the 190 screened—33 from India alone—were completely resistant to ZYMV infection, and another 64 accessions were partially resistant. They also found that ZYMV resistance is heritable in crosses between different bottlegourd accessions, enabling the development of bottlegourd varieties with enhanced virus resistance.

Breeding resistance from Lagenaria into other cucurbits may be difficult, although if they can isolate the gene(s) responsible other options become possible. And even they may not be needed. Growers can graft watermelons, for example, onto bottlegourd rootstocks and benefit from the resistance that way.

Wl020 p.s. I shouldn’t get snitty, of course, but Wikipedia’s entry on bottlegourd in China is bizarre in the extreme. I’m not going to wonder what a “remedy for health” is, though it sounds to me a lot like a disease. I am going to wonder why there is absolutely no mention of the presence absolutely everywhere of a jillion small bottlegourds as good luck charms. The Buddha used one to carry “life’s essentials”.