Category: Breeding

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Climate vulnerability in SE Asia mapped

The International Development Research Centre’s Economy and Environment Program for South-East Asia (EEPSEA) has just published a study on the effects of climate change on SE Asia. The authors first mapped climate hazard, including all kinds of different things, from drought to cyclones to sea level rise. They then compared that with maps of population density and adaptive capacity. That allowed them to identify a number of vulnerability hotspots. And here they are, the most vulnerable areas in each country:

seasia-country-hotspots

All good places in which to start looking for agrobiodiversity to collect for ex situ conservation before it disappears, and in which to test agrobiodiversity for its possible contribution to adaptation.

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Cowpea farmers profit

A press release from the International Institute of Tropical Agriculture (we picked it up at Modern Ghana.com) says that improved varieties of cowpea (Vigna unguiculata) are giving farmers 55% greater profits. The new varieties produce high quality grains and are resistant to the parasitic weed Striga. That’s great, and I have some questions.

What do we know about the heritage and breeding of the new varieties? Are they going to need replacement themselves, as pests and diseases adapt to them?

At least one was trialled in 1998 in California, and found to be possibly the best choice as a cover crop or green manure there. I wonder whether it was taken up?

Most interesting, to my mind, can we please get the full story? A quick poke around the intertubes reveals that one of these varieties — IT89KD-288 — has been around in the wild, as it were, since at least 1993, the year of “its accidental release to one farmer”. What happened? And what does it’s subsequent spread tell us about informal seed systems, farmer preferences, the role of extension services, etc. etc?

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Critically endangered cassava wild relative delays rotting

Here’s something else I learned at this workshop I’m attending on the state of plant genetic resources conservation and use in Latin America:

Dramatically delayed PPD [postharvest physiological deterioration] was found in Manihot walkerae, a wild relative of cassava found in Mexico and USA (state of Texas) (Fregene and Mba 2004). An accession of M. walkerae (MWal 001) was crossed extensively to elite cassava varieties. A single successful genotype was found with delayed PPD. The storage roots of the hybrid remained intact a month after harvest. Backcrosses of this hybrid to elite progenitors of the CIAT cassava gene pools and selfed (S1) populations were made for genetic mapping of the delayed PPD traits.

This came up during a discussion of the importance of collecting and conserving crop wild relatives. I had no idea the Manihot genus went as far north as Texas. Walker’s manioc turns out to be extremely endangered:

Until recently, it was believed that this species was represented in the U. S. by a single plant in the wild, discovered in Hidalgo County in 1990. In 1995, Walker’s manioc was located in three different areas on the Lower Rio Grande National Wildlife Refuge in Starr and Hidalgo Counties.

It is known from only a couple of populations in Mexico. I don’t give much for its chances in the wild. But there is material in the San Antonio Botanical Garden. And some of its genes are now in some cultivated varieties.