ISHS Acta Horticulturae 473: International Symposium on the Importance of Varieties and Clones in the production of Quality Wine
DEVELOPMENT OF RESISTANT ROOTSTOCKS TO CONTROL XIPHINEMA INDEX AND FANLEAF DEGENERATION |
| Authors: | M. Andrew Walker, Y. Jin |
| Keywords: | Vitis, Muscadinia, V. rupestris, M. rotundifolia, DNA markers |
| Abstract:
Fanleaf degeneration caused by grapevine fanleaf virus (GFLV) and vectored by the dagger nematode, Xiphinema index, remains one of the world's most serious grape diseases. The disease affects berry set and can result in yield reductions of 80% or greater. There are few control measures. Nematicides and fumigants have not proven effective and further development of these pesticides is limited by concerns of ground water contamination and environmental toxicity. Development of rootstocks capable of resisting X. index feeding has been underway at the University of California, Davis since the 1970s, and a Vitis vinifera x Muscadinia rotundifolia hybrid, 039–16, was released. This rootstock is limited by its potential phylloxera susceptibility, susceptibility to root-knot nematodes, and induction of high vigor to the scion. Vitis rupestris x M. rotundifolia hybrids were bred with strong resistance to X. index. A revised screening technique found a very high correlation between feeding damage and nematode numbers. Sixty of the 200 seedlings tested were resistant, and a RAPD marker produced by the Operon primer OPA-12 was found to be tightly linked to resistance. Two of these seedlings 8913–02 and 8913–21 are highly resistant to X. index, several very aggressive strains of root-knot nematode, and phylloxera. Field trials with these and other V. rupestris x M. rotundifolia hybrids are in place and are designed to test the durability of their resistance and evaluate their viticultural characteristics. | |
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