12 September 1997

Programme to

banish blight

POTATO varieties with good resistance to foliar and tuber blight are expected from a breeding programme due to start in 1998.

Potato breeder Jack Dunnett of Caithness Potatoes believes he has found the parent lines needed to combine this characteristic with resistances to common scab and pallida nematode in varieties suitable for modern markets.

"I know how to do it and have the breeding lines, but it will take time to develop true blight resistant varieties," he says. I planned to get under way next year, but the high fungal pressure of this season provided further impetus to get on with it."

The resistance, which is unlike the Pentland Dell type, is similar to that in Valor. NIAB currently gives Valor a foliar blight resistance rating of 6 and a 7 for tuber blight, compared with Caras 5 and 7, and Dells 6 and 5.

The prospect of improved blight resistance is welcomed by agronomist David Nelson of Branston Potatoes. "At the moment even the most resistant types, such as Cara, only have partial resistance," he says. "This is useful as in a low pressure season it could lead to greatly reduced fungicide use. But in a season like 1997 anything less than a full spray programme would have been asking for trouble.n

David Nelson of Lincs-based Branston Produce looks forward to better potato blight resistance in varieties of the future.