INFLUENCE OF TEMPERATURE ON EMERGENCE SOME ROOTSTOCKS USED IN ROMANIA AT GRAFTING OF CUCURBITS VEGETABLES.

The research aimed to determine the optimum temperature to a qualitative emergence (early and uniform) of some cucurbit rootstocks. The experience was carried out in 2014, inside the Laboratory of Protected Cultures, in greenhouse specialized in producing from grafted vegetable seedlings of the Research and Development Institute for Processing and Marketing of the Horticultural Products -- Horting, Bucharest. The experience has varied with following factors: rootstock and emergence temperature. The biological material used was formed from five F₁ hybrids: two inter-specific (Cucurbita moschata x C. maxima) rootstocks -- Shintoza and TZ148 and three Lagenaria siceraria rootstocks -- Argentario, Achille and Macis. Rootstocks seeds were sown in alveolar trays (24 ml/cell volume), in nutritive substrate (peat₃ : perlite₁); peat with grain size 0- 10 mm, NPK (1 kg/m³), microelements B, Mg, Cu, Mn, Zn, Fe, S (0.050 kg/m³), calcar (4.7 kg/m³), pH 6, wetting agent 100 ml/m³. After sowing and wetting, temperature was regulated in 3 different variants: 15°C, 20°C, 28°C. The germination temperature was maintained at constant value (day and night) until to plant emergence. The data were subjected to analysis of variance and compared at the 0.01 or 0.05 significance levels. Correlation coefficients were calculated between temperatures and uniformity rates in first emergence day. The statistical analysis showed differences between variants. The temperature has influenced the emergence of the rootstocks (length of time between sowing and emergence and uniformity of plants). All rootstocks had an optimal emergence at 28°C; a maximum uniformity (95%) between 4-4.5 days after sowing. An optimal emergence of the cucurbits rootstocks is an important aspect in the technology for producing of grafted seedlings. This technology is developing in Romania. [ABSTRACT FROM AUTHOR]