An on-going San Joaquin Valley wine cultivar clonal evaluation trial was initiated in 1986 and planted into the first trial block in 1987. Location is the University of California Kearney Agricultural Center, Parlier where cultural conditions and practices can be closely monitored. All of the selections are indexed FPMS sources, most of which are registered. None have ever been compared in clonal studies in California. Thus, industry would benefit from performance information on available selections. This study utilizes 15 single-vine replicates in randomized complete blocks for each cultivar. 1992 was the fourth year of comparison for three selections each of French Colombard and Chenin blanc. Each cultivar compares two different selections which are registered (indexed as virus free) but not heat treated. Additionally, each cultivar includes a heat treated selection. Thus, we are studying the possible influence of heat treatment on virus-free material of French Colombard and Chenin blanc. Barbera was in its second year of data taking. This compares an Italian selection, Rauscedo 6 (FPMS Clone 2), with Marshall (FPMS Clone 1). Barbera Clone 1 presently involves much of the present commercial acreage but was later found to contain mild leafroll. French Colombard. Clone 5 was the only selection to show significant differences in 1992, with higher yields due to heavier clusters. The heavier clusters were due to more berries per cluster. This higher yield also contributed to lower fruit soluble solids of about l°Brix as compared to Clones 1 and 2. These results were different from those of past years when Clone 1 and Clone 5 were highest and lowest in yield, respectively. Clone 2 was the best overall selection in previous years but showed no benefits in its performance in 1992. Therefore, two more years of data taking are anticipated in order to better determine long-term differences. Chenin blanc. Clone 5 again produced the smallest berries and clusters of earliest maturity. However, rot also continues to be highest with this selection. Clone 4 continues to appear to be the best selection as it has had the highest yield and lowest rot incidence in the past. It was also more fruitful than Clone 1 in 1992. Clone 4 is a heat treatment of Clone 1. This is an interesting comparison, as the heat treated selection (Clone 4) has more favorable vine yield characteristics than Clone 1. 10-1 Barbera. These two selections were included to compare the widely planted Clone 1 (Marshall) with the only registered and recently introduced Clone 2 (Rauscedo). Because of its virus-free status, Clone 2 would appear to be the recommended choice for future planting. However, its larger berry size and higher yields contribute to later fruit maturity and lower fruit anthocyanin content. Thus, harvests in future years will be made at the same stage of fruit maturation rather than calendar date. This will enable us to more accurately compare fruit composition effects on wine quality. Wines were made from all of the selections in 1992. These results will be reported at a later date when sensory analyses have been completed. Zinfandel was eliminated in 1991 due to inclusion of a misnamed selection. Grenache, Sanqiovese, and Muscat blanc trials were established in 1993 with 3 selections of each cultivar.
/wp-content/uploads/2017/09/AFV-Header-Logo.png 0 0 AVF /wp-content/uploads/2017/09/AFV-Header-Logo.png AVF1992-11-17 11:10:002017-11-17 11:10:45Clonal Testing of Winegrapes in the San Joaquin Valley