367 THE IMPACT OF DIFFERENT METHODS USED FOR IMPROVING FLOWER BIND UPON THE YIELD OF SOME TOMATO HYBRIDS CULTIVATED ON MINERAL WOOL SUBSTRATE IN INDUSTRIAL GREENHOUSES Alexandra BECHERESCU 1 , Gheorghiţa HOZA 2 , Maria DINU 3 , Olimpia IORDĂNESCU 1 , Ioan SĂRAC 1 , Daniel POPA 1 1 Banat University of Agricultural Sciences and Veterinary Medicine „King Michael I of Romania” from Timisoara, 119, Calea Aradului, Timișoara, Romania 2 University of Agronomic Sciences and Veterinary Medicine of Bucharest, 59 Mărăşti Blvd, District 1, 011464, Bucharest, Romania 3 University of Craiova, 13 A.I. Cuza Street, Craiova, Romania Corresponding author email: hozagh@yahoo.com Abstract Obtaining high and superior qualitative tomato yields, in conditions of forced culture system, being economically profitable, depends on modernizing the culture technology. In classical Venlo industrial greenhouses, modernization is possible till the technical limit allowed by their construction type. Among the technological links that can be modernized, and to which we refer in this study, are the following: cultivation of performant hybrids with high quantitative and qualitative potential (Noralee F1 and Marissa F1); fertilization during vegetation with modern chemicals, completely soluble (Yara and Haifa Chemicals), applied using drip irrigation system; using mineral wool as culture substrate (Grodan) and applying new and efficient methods for improving flower bind (pollination with bumblebees - Biobest or Natupol). This article presents the impact of all these modernized technological links upon the quantitative and qualitative tomatoes yields. Tomato-Stim determined large tomato yields, but the best results upon the yield quantity and quality were obtained from those tomato plants where natural pollination was improved by the use of bumblebees. Most of the results showed that the quality of the obtained yields (namely Extra+I st quality) finds itself in a reversed proportionality with the production quantity per hectare. The influence of both graduation of the fertigation systems are substantiated in the very close quantitative production and from a statistic point of view were not covered, as there were no significant production differences. Results lead us to recommend the cultivation of Noralee F1 hybrid, the use of any of the fertilizers Yara and Haifa Chemicals via fertigation and the use of bumblebees (Biobest or Natupol) to improve the tomato flower binding and to obtain superior quality fruits. Key words: bumblebees fertigation, quality. INTRODUCTION Modernizing the culture technology for vegetable cultivated in a protected or forced system, consists in improving some techno- logical links (improving flower bind degree, using modern fertilizers, performant hybrids etc.) so that the effect would be and efficient yield, considering its productivity, quality and economic efficiency (Horgoş A. et al., 2002). Today, tomatoes is widely cultivated throughout the world and adapted into many cultivars (Olmstead and Palmer, 1997). The replacement of soil, as natural culture substrate, in greenhouses with an artificial culture substrate, in this case mineral wool, represents an important technological link in the modernization process as it determines the improvement of other technological links, which are irrigation and fertilization at the same time by using the drip-irrigation system (fertigation). (Horgoş A. et al., 2005). Bumblebees are important pollinators for tomato crops. Foragers are capable of assessing the pollen reward of the flowers, the first flower visit is the most effective concerning pollen removal and, consequently, pollination, and small foragers are as efficient in pollinating tomato flowers as are big ones. In line with some earlier studies (Buchmann and Cane 1989; Harder, 1990; Shelly et al., 2000) provide clear evidence that bees are indeed Scientifc Papers. Series B, Horticulture. Vol. LXII, 2018 Print ISSN 2285-5653, CD-ROM ISSN 2285-5661, Online ISSN 2286-1580, ISSN-L 2285-5653