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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”.

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Intensifying rice

WWF has a news release today announcing the publication of a study on the System of Rice Intensification (SRI), a set of practices initially developed in Madagascar in the 1980s. ((If you’re wondering why WWF is publishing a report on agriculture: “WWF is focusing on sustainable agriculture efforts for cotton, sugar and rice, some of the most consuming crops for which alternative techniques can result in a strong yield and water savings.”))

The system is based on eight principles which are different to conventional rice cultivation. They include developing nutrient-rich and un-flooded nurseries instead of flooded ones; ensuring wider spacing between rice seedlings; preferring composts or manure to synthetic fertilizers; and managing water carefully to avoid that the plants’ roots are not saturated.

The WWF study says SRI is more water-efficient and productive: in India, yields have apparently risen by 30%, while water use has decreased by 40%. No word on its effects on local agrobiodiversity. Yet. But methane emissions are supposed to go down. Nevertheless, there has been some criticism of SRI in the past.

Continue reading “Intensifying rice”

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Linking archaeology and agrobiodiversity

It was probably a silly thing to say. A couple of days ago I briefly mentioned the models that researchers have built, based on present-day genetic data on Europeans, to understand the rate and pattern of human movement into the continent during the Neolithic. And I made the throw-away comment that I wasn’t aware of similar models for crops. I sort of instantly regretted it, and last night did some googling.

At first I thought perhaps I was right after all. I found a recent (2006) paper whose abstract says:

Thus far, no attempts have been made to track the movement of the founder genetic stocks of the first crop plants from their core area based on the genetic structure of living plants.

Further on, though, the authors say they’ve done just that for wheat. And I also found reference to a “Domestication of Europe” project which sought

to determine the extent to which phylogeographical analysis of modern landraces of barley and wheat, combined with examination of ancient DNA in preserved specimens, can reveal genetic information pertaining to the spread and establishment of cereal cultivation from its points of origin in Southwest Asia into and through Europe.

I think the project must have run from 2003-2006. The Glyn Daniel Laboratory for Archaeogenetics at Cambridge was one of the labs involved, and some of the work, and other related research projects, is described on its website.

So there are people out there trying to link up the archaeology and human genetics of agricultural spread in Europe with the genetics of crops and livestock. Is it too early for a Grand Synthesis?

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Conserving crop wild relatives

A paper just out in Biological Conservation discusses crop wild relatives (CWR) in the UK. ((Creation and use of a national inventory of crop wild relatives. Biological Conservation. In Press, Corrected Proof. Available online 27 September 2007. Nigel Maxted, Maria Scholten, Rosalind Codd and Brian Ford-Lloyd.)) The authors include some of the same British boffins who wrote a global survey of CWR conservation. The paper describes how to develop a comprehensive national plan for the conservation of CWR, using the UK as an example. Unfortunately, it is behind a paywall, but I’ll summarize the main points.

First, of course, you need to know what you’re dealing with. A UK national inventory of CWR was developed as part of the EU-funded PGR Forum project. It contains 15 families, 413 genera, 1955 species (44 endemic) — that’s 65% of the native flora. So then you have to prioritize. For example, 13 of the UK’s CWR species are considered threatened according to IUCN criteria and one is apparently extinct in the wild ( the grass Bromus interruptus). The authors ran an iterative algorithm on the distribution data for about 250 CWR species ((Chosen because of their potential economic value and perceived threat level.)) to identify the smallest number of areas which would contain the largest number of species. Seventeen 10×10 km grid squares were selected within which could be found two thirds of the priority CWR species.

To what extent are these “hotspots” already protected? Interestingly, none of them “did not overlap with existing UK protected areas.” What’s now needed is to confirm the presence of the target species in the protected areas and come up with management plans specifically aimed at the CWR.