Wetenschap - 3 november 2012

Breakthrough in developing salt-tolerant crops

PhD researcher Nguyen Viet Long has discovered gene packs in barley which make this crop salt tolerant. This knowledge can also be applied to wheat and rice. Long obtained his doctorate yesterday.


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Salinization is affecting more and more agricultural soils in the world, preventing crops from growing well. If the water in the soil is more salty than the moisture in the plant, the plant cannot take in as much water as it needs, and all kinds of processes in the plant can go haywire. Of the major farm crops, barley is the most salt tolerant.
Long tested many barley varieties in various salt concentrations and then searched for genetic differences among these varieties. In this way, he discovered 11 areas in the barley genome which regulate salt tolerance. Further DNA analysis showed that two areas in the genome assert the most influence. A gene pack in chromosome 4 ensures that the salt in the plant does not reach its leaves and cannot disrupt photosynthesis. A gene set in chromosome 6 regulates the intake of brackish water by the plant so as to minimize disruptions in water regulation in the plant.
This knowledge will enable breeders to start developing salt tolerant barley varieties. The importance of this must not be underestimated, says Long's supervisor Gerard van der Linden, because barley is the world's fifth major staple crop, after rice, wheat, maize and potatoes. In Europe, barley is used mainly for the production of beer and whisky.
Of equal importance is the fact that barley is a type of model crop in the research into salt-tolerant crops. The knowledge acquired by Long will make it easier for researchers and breeders to search for genes in, for example, wheat and rice so that these crops too can be made tolerant in brackish soils. This is important, for example, in Long's homeland, Vietnam, where rice cultivation in the Mekong Delta is being plagued by salinization.
The gene set found by Long in chromosome 4 of barley has also been found lately by other researchers in wheat. But Long is the first to make the discovery in chromosome 6, in which other plant scientists have a great deal of interest. Long expects the first salt-tolerant barley crop to be marketed in five years' time. This may take longer for other crops. Salt tolerance is a complex characteristic, says Van der Linden, which always involves a combination of genes in many chromosomes.
Nguyen Viet Long obtained his PhD on 2 November under Professor Richard Visser of Plant Breeding.