This is the conclusion of the STW-sponsored thesis by Richard Finkers from Wageningen University, with which he hopes to earn his doctorate on 3 April 2007. Finkers designed highly efficient methods whereby tomato varieties can be resistant to grey mould. The company De Ruiter Seeds is already applying these methods in its breeding programme.
Finkers started off with wild tomato accessions that were resistant to grey mould. When crossing the resistant wild tomato Solanum habrochaites LYC4 with the susceptible S. lycopersicum cv. Moneymaker, he identified two areas with resistant genes in the DNA.
This, however, did not explain all the variations in resistance. With this in mind, Finkers next made a step-by-step scan of the entire genome of the wild tomato to identify locations that have an effect on resistance. Ten areas were found that accommodated resistance factors against grey mould. DNA-markers were then developed for each area to be able to track the presence of each resistance factor in breeding programmes.
Resistant tomatoes for sale
With help of the DNA-markers, the identified areas can now be intentionally introgressed in the breeding programmes of De Ruiter Seeds, a Dutch company with a global reputation in the field. Using the DNA-markers, it expects to market new tomatoes that are resistant to grey mould in the near future. The new varieties will mean tomato growers will have to devote far less resources � or perhaps none at all � to combating B. cinerea.
An additional benefit of these new tomatoes is that they will be more suitable for closed glasshouse cultivation. This new type of glasshouse has a higher atmospheric humidity that actually increases the chance of grey mould activity. By providing tomato varieties resistant to grey mould, De Ruiter Seeds will fill a worldwide need that has long been around.
The research was partly financed by STW (the Technology and Sciences Association) and De Ruiter Seeds. As the developed knowledge obtained from this research has been patented, and therefore both protected and made accessible.
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