Phenological Changes of Leaf Nutrients in Vitis labrusca L. Grape Grafted on Different Rootstocks in Heavy Clay Soil Conditions

The present study was conducted to determine the phenological changes in leaf nutrient contents in 10-years Vitis labrusca L. grapes grafted on 140Ru, 5BB and 5C rootstocks. In the experiment, changes of leaf macro and micro element contents from bud burst to post harvest period were investigated in the heavy clay soil conditions. Nutrient contents of leaf blades showed varied depending on the phenological stages and rootstocks (P < 0.01). P, K, Mg and Ca levels of leaf blade exhibited significant differences based on rootstocks and phenological periods between blooming and veraison. While Zn level was obtained sufficient on 5BB of grafted grapevines, it was found to be insufficient in grapevines grafted on 140Ru and 5C rootstocks. In general, grapevines were found insufficient for P, K and Mg nutrients. Total chlorophyll contents of leaves were found at high in the blooming period. Although the highest chlorophyll contents were found in the blooming period, it was determined at the lowest through to harvest. In the study, 5BB rootstock was evaluated to be favorable in terms of nutrient uptake.     

Comparison of the Salt Stress Tolerance of Promising Turkish Winter Squash (Cucurbita maxima Duch.) and Pumpkin (Cucurbita moschata Duch.) Lines and Interspecific Hybrids

The objective of this study was to evaluate several selected Cucurbita genotypes for their salt resistance in a rootstock breeding program for grafted watermelon seedling production. Specifically, changes in the relative water content (RWC), leaf area (LA), total chlorophyll content (TCC) and proline concentration (PC) of a commercial cultivar (G32 code), two promising winter squash (G12 and G13 of Cucurbita maxima Duch.) lines, six pumpkin (G3, G27, G28, G29, G30 and G31 of Cucurbita moschata Duch.) lines, and four C. maxima?×?C. mochata hybrids (G14, G15, G40 and G42), were investigated with a control treatment and four levels of salt stress (4, 8, 12 and 16?dS/m). In this study, Cucurbita cultivars which showed significant differences according to RWC, LA, TCC and PC at least significant difference (LSD) tests (P?<?0.05) and had salinity sensitivity index (SSI) value lower than 20%, were assessed as salt tolerant genotypes. The salt tolerant genotypes were grouped with principal component analysis (PCA) in each salt level. At the end of the study, all genotypes for all characteristics were generally tolerant at 4?dS/m salinity level. The G3, G12, G13, G14, G29 and G42 genotypes were resistant at 8?dS/m salinity, while the G15, G31, G32 and G40 were the most resistant genotypes at 12 and 16?dS/m. In conclusion, the selection of more salt resistant cultivars in rootstock breeding programs should be a priority to maintain growth performance in saline environments.