Grape plants developed by Agritope Inc. may be the solutionfor the thousands of acres of California wineries devastated bythe root-destroying bug phylloxora.

A subsidiary of Beaverton, Ore.-based Epitope Inc., Agritopeused its micropropagation and micrograft techniques for rapidproduction of resistant rootstock to develop more than 30rootstock and scion varieties.

Al Farrow, Agritope's president and chief executive, believesthat Agritope is the first company to hit upon a viable solutionfor phylloxera. He told BioWorld that six undisclosed majorCalifornia growers are using Agritope rootstocks as part of thecompany's grower evaluation program.

With no chemical method of controlling the vine-killing louse,replanting some 12,000 infested acres in California's Sonomaand Napa counties represents a costly and time-consumingprocedure.

According to Farrow, until now there hasn't been a demand foralternative resistant rootstocks, aside from AXR1, with whichmost California vineyards are planted.

"The word about Phylloxera didn't get out quick enough here(in California), and now the problem is getting enough resistantrootstock to replant," Farrow said.

Agritope's grape plants, named Vitrovine, are produced viamicropropagation using a nodal culture method. Nodal tissuefound along the length of the stem can generate a whole plantand are used to produce new grape shoots. Each node grown inculture is used to produce a shoot with three to four "daughter"nodes, which may be divided into individual nodes for furthermultiplication.

Advantages of Agritope's technique include the ability toproduce a large number of grape shoots, as each multiplicationcycle requires only about four weeks. Also, the plant's geneticmakeup is not altered, so all clones remain true to type.

The company's micrograft technique eliminates the traditionaltwo-year maturation process required for grafting the youngscion material to rootstock.

Having to produce consistent varietal characteristics andmillions of disease-free plants in the same time that it takes togrow 100 plants by traditional methods is putting heavydemands on Agritope's micropropagated rootstocks, bothcommercially and for research, Farrow said.

"Some companies have already placed orders with us for the1992-93 growing season, at a cost anywhere between 50 centsand $6 per rootstock," said Farrow.

John De Benedictus of the University of California, Davis,phylloxera task force set up in 1989 to investigate the plague,said replanting vineyards with Phylloxera-resistant rootstock iscurrently the only method to offset vine losses. He estimatedthe cost of restocking Napa and Sonoma vineyards at between$18,000 to $24,000 per acre.

Although he has confidence in Agritope's technology, ChuckWagner, general manager at Caymus Vineyards in Napa, saidAgritope's prices may be too high. "I don't think the marketwill bear costs as high as $6, especially when you considerwe're planting over 1,000 vines per acre."

Wagner said 600 experimental vines planted at Caymus lastyear are doing very well, and his only apprehension is that theidea is new. "Farmer's like to see what their neighbor is doingfirst,"said Wagner. "There's no doubt that Agritope's rootstockworks, but cost is a question."

Pete Optaz, vineyard manager at Chateau St. Jean of Kenwood,Calif., said that Agritope's technology offers options for growersto maintain diverse plant varieties. "I think Agritope presentsitself as a solution (to phylloxera)," he said. "They're the oneswilling to present themselves as the first to use in-vitropropagation."

Optaz does not think the current problem is as great as someanalysts do. Supply of grapes in the short term is notsignificant, said Optaz, because of a current market glut of winegrapes. Some estimates have placed grape shortfalls as high as40 percent, which Optaz agreed would be a serious problem.But he estimates a shortfall of no more than 10 percent to 15percent.

Agritope has a patent pending for the method ofmicropropagation with grapes, but Farrow could not givedetails as to when the patent was filed or other related patentsthat the company has pending.

Farrow said the company's future plans include a projectfocusing on two approaches to destroy the bug.

Farrow said that one of Agritope's method uses geneticallyengineered plants resistant to all phylloxera biotypes of thelouse so that even if it mutated, a plant's resistancecharacteristic would not be affected. He declined to discuss thesecond approach, but said that it would not use geneticengineering techniques.

-- Michelle Slade Associate Editor

(c) 1997 American Health Consultants. All rights reserved.