825 ● October–December 2005 15(4) Influence of Wine Grape Cultivars on Growth and Leaf Blade and Petiole Mineral Nutrients Esmaeil Fallahi 1 , Bahman Shafii 2 , Jeffrey C. Stark 3 , Bahar Fallahi 4 , and Saad L. Hafez 5 ADDITIONAL INDEX WORDS. adaptability, leaf analysis, partitioning, Vitis SUMMARY. Cane growth, leaf blade area, blade and petiole fresh and dry weights and mineral nutrients of six grape (Vitis vinifera) cultivars were evaluated in 2000 and 2001 under climatic conditions of southwestern Idaho. The cultivars were: ‘Barbera 02’, ‘Cabernet Sauvignon 02’, ‘Cabernet Sauvignon 04’, ‘Char- donnay 29’, ‘Merlot 01’, and ‘Sangiovese 04’. No differences were found in cane growth of different cultivars. ‘Sangiovese 04’ and ‘Merlot 01’ had larger leaf area and heavier leaves (both blades and petioles) and higher concentrations of blade nitrogen (N), while ‘Merlot 01’ and ‘Chardonnay 29’ had higher petiole nitrate- N than all other cultivars. ‘Merlot 01’ had relatively the highest potassium (K) concentrations in both blade and petiole tissues. ‘Chardonnay 29’ had lower concentration of calcium (Ca) and ‘Sangiovese 04’ had lower concentrations of magnesium (Mg) in both blade and petiole tissues than other cultivars although differences were not always significant. ‘Barbera 02’ had higher blade iron (Fe) and tended to have higher blade copper (Cu) than other cultivars. However, ’Chardonnay 29’ had higher petiole Fe than ‘Barbera 02’, ‘Cabernet Sauvignon 04’, and ‘Sangiovese 04’. ‘Merlot 01’ had higher blade manganese (Mn) than ‘Sangiovese 04’. W ine grapes have been grown in southwestern Idaho since the early 1960s. In 1999, there were 266 ha of wine grapes in southwestern Idaho (Idaho Agricul- tural Statistics Service, 2003), increas- ing to approximately 445 ha in 2004 (personal knowledge). In spite of many favorable environmental conditions in southwestern Idaho, wine grapes in the region are subjected to the risk of severe winter injury in some years. However, since phylloxera (Phylloxera vitifoliae) has not been found in Idaho, most wine grapevines are established on their own roots. Thus, when severely low winter temperatures damage the upper portions of the vines, they may regrow and a new canopy can be estab- lished. Adaptability and fruit quality of wine grape cultivars in a region should be studied before they are widely planted, and several such studies were conducted for different regions of the U.S. (Adams, 1985; Cahoon, 1996; Fallahi et al., 2004, 2005; Hamman, 1993; Kaps and Odneal, 2001; Mielke, 1980; Pinney, 1989; Sexton, 1987; Wolf and Miller, 2001). A considerable volume of infor- mation is available on the effects of fertilizer applications (Cook, 1966; Robinson, 1999), irrigation and can- opy development (Robinson, 1999), and rootstock (Cook and Lider, 1964; Downton, 1977) on grape leaf mineral concentrations. Vine mineral nutrients in wine grapes not only influence yield and cane growth (Goldspink, 1987; Robinson, 1999; Weir, 1987; Winkler et al., 1974) but also affect wine quality (Amerine and Joslyn, 1970; Somers, 1975). There have been widely varied opinions among viticulturists for many years regarding the developmental stage, type of tissue (blade vs. petiole), and leaf position selected for mineral analysis; to best represent optimum nu- trient status for wine grape growth and fruit quality (Cook, 1966; Robinson, 1999). The French Diagnostic Foliar laboratory at Montpellier relied upon leaf stalk (blade and petiole) tissue, sampled twice from each vineyard, one at bloom time and the other at veraison (Cook, 1966). A similar protocol is still practiced when more precise informa- tion on the foliar mineral status of a vineyard is needed (Pinney, 1989). However, following an early report by Ulrich (1942), petiole tissue alone, sampled at bloom time, is often used for mineral nutrients in California (Christensen, 1984; Cook and Lider, 1964). Also, for determination of ni- trate-N, a petiole sampling at anthesis is recommended in the Australian grape industry (Robinson, 1999). In spite of the considerable com- mercial wine grape production and potential for expansion in the inter- mountain western U.S., there is limited information on the canopy growth, leaf size, and leaf mineral status of cultivars in the region. Therefore, the objective of this research was to study cane growth, leaf size, and leaf mineral nutrients in six wine grape cultivars grown under climatic conditions of southwestern Idaho (intermountain western U.S.). Materials and methods The experimental vineyard, con- sisting of six cultivars of wine grapes, was established at the University of Idaho Parma Research and Extension Center in southwestern Idaho in Spring 1998. The experimental vineyard was oriented at lat. 43°48’00” and long. 116°57’00” with 2305-ft elevation. The site of the experimental vineyard had a long-term average annual pre- cipitation of 10 inches with average minimum temperature of 19.2 °F (in January) and maximum temperature of 1 Professor and Research Leader of Pomology Program, University of Idaho, Parma Research and Extension Center, 29603 U of I Lane, Parma, Idaho 83660. 2 Professor of Plant Science and Director of Statistical Program, University of Idaho. 3 Professor and Division Chair of Horticulture, Plant Physiologist, University of Idaho. 4 Scientific Aid Senior, Pomology Program, University of Idaho. 5 Professor and Director of Nematology Program, University of Idaho. Units To convert U.S. to SI, To convert SI to U.S., multiply by U.S. unit SI unit multiply by 0.3048 ft m 3.2808 3.7854 gal L 0.2642 2.5400 inch(es) cm 0.3937 6.4516 inch 2 cm 2 0.1550 28.3495 oz g 0.0353 28,350 oz mg 3.5274 × 10 –5 1 ppm μg·g –1 1 (°F – 32) ÷ 1.8 °F °C (1.8 × °C) + 32