Evaluation of Selected Mediterranean Wine Grape Cultivars and Clones in Lake and Mendocino Counties

During the year 2000, phenological and harvest data were taken from three Mediterranean Winegrape Cultivar Test Plots in Lake and Mendocino Counties. Results indicate that there are tremendous differences in budbreak, yield and harvest dates between the cultivars and locations.

In Lake County, all cultivars reached ripeness (23.5 brix) in the Red Hills plot, whereas only the earliest cultivars reached ripeness in the Highland Springs plot. This can be explained partially by the warmer climate of Red Hills, but also by the smaller crop size and lighter soils in that plot compared to larger crops and heavier, cooler soils found in Highland Springs. In general, the ripening sequence is as follows: Pinotage, Barbera, Dolcetto, Grenache, Nebbiolo, Cabernet sauvignon, Sangiovese, Cinsault, Syrah,. Harvest occurred from Sept.15, to Oct. 27th, 2000. At Highland Springs, only Pinotage fully ripened during the 2000 harvest.

At the UC Hopland Research and Extension Center, there is a greater number of cultivars being tested. Ripening sequence this year was Pinot gris, Viognier, Tempranillo, Cinsault, Grenache, Syrah, Sangiovese, Dolcetto, Viognier (?Bonny Doon? clone), Fiano, Freisa, Mourvedre, Nebbiolo, Corvina, and Aglianico. Canailo nero, Montepulciano and Marsanne failed to adequately ripen, and were lost due to rain damage. A research progress report of the UC HREC data is being prepared for a California Agriculture magazine issue featuring the 50th anniversary of the UC Hopland Research and Extension Center.

In nearly all cases, quality of the fruit was quite high, showing adequate sugar (23.5 brix), good acidity, and very little rot. For the combined trials, 22 lots of wine are being fermented. It is clear that there are many cultivar options for quality winemaking in Lake and Mendocino Counties.

We were not able to plant a clonal trial of Syrah during this season. Vines will be planted in 2001. Evaluations of 5 Syrah clones were made from commercial plantings at McDowell Valley Vineyards. Clones include Syrah noir (?Hermitage? clone), Shiraz (UC clone #1), McDowell clone, CTPS #877, and CTPS #174. Significant differences in cluster size, shape and yield per vines were noted, as well as must chemistry. Separate lots of wine were vinified, and there are definite organoleptic differences between the clones. While not statistically valid, these observations are still helpful in assessing differences between the Syrah clones. Information from this survey will be presented at the ASEV Syrah Symposium in San Diego in June, 2001.

PDF: Evaluation of Selected Mediterranean Wine Grape Cultivars and Clones in Lake and Mendocino Counties