Agricultural Biodiversity Weblog

January 29, 2015January 29, 2015

Wild potato diversity halved

David Spooner and co-workers have written a comprehensive overview of the systematics and genetics of wild and cultivated potato species (Solanum section Petota) ¹. This nicely illustrated and very accessible paper is essential reading for anyone interested in potato diversity — or indeed the study of plant diversity in general.

A remarkable aspect of wild potato systematics is the way the number of recognized species has fluctuated over time. In 1956, Hawkes recognized 106 species, but in his 1990 treatment of the group this had increased to 232. This will likely be the highest number we’ll see, because it has come down drastically since, and Spooner et al.’s paper puts it at 107 — almost exactly where it was back in 1956. This does not mean that we are back to the same set of taxa though. Many new species were described after 1956, notably by Carlos Ochoa, who named about 25% of the 107 species. ²

The graph below shows the number of species over time, based on published compilations, and the name of the authors ³ .

It is not easy to determine where a wild potato species begins and where it ends. Many species look very similar, and there is “lack of strong biological isolating mechanisms and the resulting interspecific hybridization and introgression, allopolyploidy, a mixture of sexual and asexual reproduction, and recent species divergence.” A smaller number of species is not necessarily better, but, in the case of wild potatoes, Spooner et al. think it will help us move away from “a taxonomy that is unnatural, unworkable, and perpetuates variant identification” to a system that hopefully enables better conservation and use of these plants.

It also creates a mess, though, because previous analyses based on species level diversity, for example to set collection and conservation priorities, may need to be revised. Spooner et al. update some of the analysis of geographic pattern in wild potato species richness described previously.

The reduction in the number of species is in large part due to new insights from David Spooner’s incessant work on this group, through molecular and morphological studies, and observations during collecting expeditions. His kind of naturalist is a species that is also declining in numbers, or so it seems. That is not a good thing, as there is a lot of work to do.

January 26, 2015January 18, 2015

Brainfood: Organic convergence, Wine yeast diversity, Cassava genome, Potato wild relatives, PREDICTS predicts, Seed cryo, Community seedbanks, Maize OPV evolution, Conservation conflict, Biofortification

Organic and Non-Organic Farming: Is Convergence Possible? Yes, but conversion is more likely.
The vintage effect overcomes the terroir effect: a three years survey on the wine yeast biodiversity in Franciacorta and Oltrepò Pavese, two Northern Italian vine-growing areas. Year more important than place as determinant of yeast diversity.
Cassava genome from a wild ancestor to cultivated varieties. The genes that have been selected are the ones you’d think. And here’s the thing actually being used.
Taxonomy and Genetic Differentiation among Wild and Cultivated Germplasm of Solanum sect. Petota. The genes that have been selected are the ones you’d think. Oh, and the taxonomy is fine.
The PREDICTS database: a global database of how local terrestrial biodiversity responds to human impacts. Could prove useful. But it doesn’t look like the data is available yet.
C-2001: Survival of short-lived desiccation tolerant seeds during long-term storage in liquid nitrogen: Implications for the management and conservation of plant germplasm collections. It’s not always great.
Ensuring food security in the small islands of Maluku: A community genebank approach. Won’t be easy.
Evaluation of Evolution and Diversity of Maize Open-Pollinated Varieties Cultivated under Contrasted Environmental and Farmers’ Selection Pressures: A Phenotypical Approach. Maize OPVs changed a bit in farmers’ fields over 3 years, but not in how they looked.
Conservation planning in agricultural landscapes: hotspots of conflict between agriculture and nature. Threatened mammals and cropland areas where yield gap is highest are, not surprisingly, mostly found together in sub-Saharan Africa. I wonder if the same could be said for threatened crop wild relatives?
Biofortification for Selecting and Developing Crop Cultivars Denser in Iron and Zinc. Current strategy is QTL detection followed by MAS, but much more downstream work on processing, extension and acceptance needed.

January 23, 2015

Sweet potato expert passes away

Very sad to hear of the passing a few days ago of Dr Daniel F. Austin. Among other things, he was one of the world’s top experts on the biodiversity of the sweet potato and its wild relatives.

January 22, 2015January 21, 2015

Tracking down Chinese pigs

The most obvious impact has been on the pigs themselves. Until the 1980s farms as large as Mr Ouyang’s were unknown: 95% of Chinese pigs came from smallholdings with fewer than five animals. Today just 20% come from these backyard farms, says Mindi Schneider of the International Institute of Social Studies in The Hague. Some industrial facilities, often owned by the state or by multinationals, produce as many as 100,000 swine a year. These are born and live for ever on slatted metal beds; most never see direct sunlight; very few ever get to breed. The pigs themselves have changed physically, too. Three foreign breeds now account for 95% of them; to preserve its own kinds, China has a national gene bank (basically a giant freezer of pig semen) and a network of indigenous-pig menageries. Nevertheless, scores of ancient variants may soon die out.

That comes from an article in the Christmas edition of The Economist dissecting the consequences of the vertiginous increase in pork consumption in China since the liberalization of agriculture in the 1970s. I tried to find out more about that pig genebank, but it hasn’t been easy. The Country Report for the First Report on the State of the World’s Animal Genetic Resources mentions State Domestic Animal Gene Banks in Beijing and Jiangsu, but adds few details. I suspect the institute in question is CAAS’s Institute of Animal Sciences, but its website does not help much. Wherever it is, the Chinese national pig genebank is going to be busy. DAD-IS lists something like 125 named pig breeds from China, from the Anqing Six White to the Zhejiang Middle Large. One of them — the Wuzhishan — has even had its genome sequenced. On the other hand, it may not be so bad, as according to a 2003 paper, “extensive research on pig genetic diversity in China indicates that these 18 Chinese indigenous breeds may have one common ancestor…”

Incidentally, another agrobiodiversity-themed article in the same issue of the magazine deals with the turkey, and is a nice complement to Jeremy’s two forays into that succulent subject over at Eat This Podcast.

January 21, 2015January 21, 2015

Chefs help conserve peanut butter and jelly sandwiches

I believe we have Nibbled both of these articles, but I think they could stand another few minutes in the limelight. One describes how self-described “farmer-scientist” Dr Brian Ward of Clemson University — with a little help from his friends — is bringing back from near extinction a peanut variety called Carolina Africa Runner:

Luckily, in the 1940s North Carolina State University collected samples of a variety of peanuts during a breeding program, and the Carolina’s germplasm was preserved.

The second article is about maverick Washington State University breeder Dr Stephen Jones’s attempts to come up with better tasting bread.

Several years ago, he started a project called the Bread Lab, a Washington State program that approaches grain breeding with a focus on the eventual culinary end goal. The idea came about because Jones says he was tired of the USDA and Big Ag dictating the traits that he needed to breed for. “They would tell us [a certain wheat variety] doesn’t make a good loaf of bread. Well, what they meant was an industrial, high-speed, mixing, full of junk, white — just lily-white — bread,” Jones says. “And we didn’t want that opinion, so we had nowhere to go.”

~~What~~One of the several things the stories have in common is the involvement of chefs. Now, there must also be one out there interested in heirloom fruits. Then we could bring them all together…