In the future, plant breeders may be able to develop potato varieties that are better able to withstand long drought spells than the currently grown varieties.
This is the outcome of PhD study carried out by Anitha Kumari in March 2011 at Wageningen University, part of Wageningen UR. Kumari discovered huge differences in the ability of potato plants to recover from drought spells. In addition, she also discovered one specific region in the potato genome that harbors the genes that regulate the response to drought of her potato plants.
Potatoes use water very efficiently. A potato plant produces more calories per litre of groundwater than wheat, for example. However, tuber yield decreases rapidly when water is scarce and plants suffer from drought. Kumari’s results indicate that it would probably be feasible to develop potato plants that not only use water efficiently, but that also recover well enough to produce high yields after a drought spell.
The researcher from Wageningen first carried out a large-scale study on the role of hereditary traits of potato plants in response to drought.
For her research, Kumari used a population derived from two potato plants with a diverse genetic background, originating from two different wild potato species. She planted this population in the greenhouse and left them without water for approximately three weeks to induce drought stress. After rewatering, some of the potato plants recovered well, while others died. This demonstrates that traits that can enhance drought tolerance are available in this population, which can be utilized to develop potatoes that are more tolerant to drought spells.
In her study, Kumari investigated whether the genes in the potato plants had an increased or decreased activity at the beginning of the dry spell. She discovered that more than a thousand genes specifically responded to the dry conditions.
Genetic analysis of the potato plants demonstrated that the differences in the activity of many of these genes rely on one specific area in the DNA of the investigated potatoes. This regulatory region was only active under drought, and not under normal conditions, which led her to conclude that a major controller of the plants’ early response to drought is probably located within this region of the DNA.