Browsing by Author "Southey, J. M."
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- ItemThe effect of grapevine rootstock on the performance of vitis vinifera L. ( cv. colombard) on a relatively saline soil(South African Society for Enology and Viticulture, 1991) Southey, J. M.; Jooste, J . H.The performance of grapevine cv. Colom bard grafted onto 25 rootstocks (1045P, 1103P, 775P, 99R, (RY 13), 99R (RY 2), UOR, 140Ru, 143-B Mgt, 101-14 Mgt, Ramsey, 13-5 EVEX, Constantia Metallica, Jacquez, Grezot 1, 216/3 Castel and US hybrids, 1-6, 3-6, 4-4, 2-1, 24-41, 24-10, 35-1-15, 16-13-23, 16-13-26and12-6-8] on relatively saline soils was investigated for six years. The highest yields were obtained with 13-5 EVEX, Ramsey, 143-B Mgt, 1045P and 140 Ru, whereas the US hybrids generally performed poorly, particularly those with Jacquez in their parentage. At this early stage in the trial a highly positive correlation·between yield and cane mass was found. Although total soluble solids concentration and pH generally declined with increasing yield and cane mass, differences in grape ~omposition appeared to be largely the result of differences in actual maturity.
- ItemPhysiological response of vitis vinifera L. (cv. chenin blanc) grafted onto different rootstocks on a relatively saline soil(South African Society for Enology and Viticulture, 1992) Southey, J. M.; Jooste, J. H.Certain physiological parameters, namely leaf water potential, stomatal resistance and rate of photosynthesis of Chenin blanc grafted onto 10 rootstock cultivars on a relatively saline soil under irrigation in a hot region (V), were measured for two growing seasons. Soil electrical resistance, which varied from 632 to 271 ohms in the shallower soil layers (<500mm) and from 414 to 167 ohms deeper in the soil, decreased during the growing seasons. Although diurnal and seasonal patterns of change of the physiological parameters measured did not differ between rootstock cultivars, significant differences in their magnitudes were apparent. The rootstocks US 16-13-23, 13-5 E.V.E. Jerex were more stressed than 101-14 Mgt, 143-B Mgt and 110 Richter and had lower rates of photosynthesis. Photosynthetic rate was predominantly inversely correlated with stomatal closure. The use of 101-14 Mgt and 143-B Mgt is recommended under relatively saline conditions.