Super spud!
humble potato is up there in the number one glory spot as America's
favourite vegetable. But this all time fave is a vulnerable sort,
with tuber defects a regular affliction. Researchers at the US
Department of Agriculture claim to have come up with a healthy
solution - calcium.
Baked, creamed, hashed, fried or sauteed - however it comes, the humble potato is up there in the number one glory spot as America's favourite vegetable. But this all time fave is a vulnerable sort, with tuber defects a regular affliction. Researchers at the US Department of Agriculture claim to have come up with a healthy solution - calcium.
Jiwan Palta, a physiologist at the University of Wisconsin-Madison (UW) and geneticist John Bamberg at the US Agricultural Research Service, claim that increased concentrations of calcium in potato tissue have been shown to reduce the severity of tuber defects such as internal brown spot and hollow heart. Increased levels of tuber calcium have also been correlated with improvements in tuber yield, grade, and storage quality.
"Potato tubers are naturally deficient in calcium," said Palta. "They grow underground-usually in sandy, irrigated soil-and have about one-fifth the calcium found in the aboveground stem of the plant."
Palta explained that the plant's main root system draws water and a water-soluble form of calcium from the soil and sends them where they are needed most-the plant stem and leaves. Because the potato tuber is surrounded by moist soil, it transpires less and accumulates much less calcium.
"Applying 100 to 200 pounds of water-soluble calcium per acre during bulking vastly improves tuber quality," continued Palta. "In general, we've found that the average calcium concentration in tubers increases 50 to 100 per cent, and the incidence of internal defects dramatically declines."
With this knowledge in hand Palta and Bamberg set out to investigate whether certain species were better than others at accumulating the mineral.
"We identified two wild species that are excellent calcium accumulators: S. gourlayi and S. microdontum," said Bamberg. S. gourlayi ranked first for calcium accumulation in the control environment, accumulating more than double that of S. tuberosum, the only cultivated potato species.
"Both these wild species are in the same taxonomic series as cultivated potato species, so they can be crossed with S. tuberosum, " added Bamberg.
After making their initial findings, Bamberg and Palta began screening potato plants for extremes of calcium-accumulation capacity. As a result, they were able to identify potato germplasm with very high and very low calcium-accumulation capacity.
So what's next on the agenda? The scientists will now start to transfer the genes for super-high tuber calcium accumulation from the wild species to the cultivar breeding pool. The superspud is born!
