Growth dynamics of tomato seedlings treated with growth enhancers

Uzgoj presadnica rajčice u zimsko-proljetnom periodu traje relativno dugo (od 70 do 90 dana), što uzrokuje visoke troškove grijanja, odnosno proizvodnje. Odabirom odgovarajućeg roka sjetve te primjenom poboljšivača rasta moguće je skratiti period uzgoja. Cilj ovog istraživanja je utvrditi utjecaj odabranih poboljšivača rasta na dinamiku rasta presadnica rajčice u četri različita roka sjetve, u usporedbi s netretiranim presadnicama. Istraživanje je provedeno u grijanom zaštićenom prostoru Zavoda za povrćarstvo Agronomskog fakulteta u Zagrebu. Sjeme rajčice sorte 'Rutgers' sijano je u polistirenske kontejnere sa 104 lončića u četiri roka sjetve (26. veljače te 9., 19. i 30. ožujka 2015.). Odmah nakon pikiranja te još dva puta u razmaku od 10-12 dana presadnice su folijarno tretirane poboljšivačima rasta Bio- Plantella super F i Ekorast, u koncentraciji od 0,15 %. Prilikom svakog tretiranja obavljena su morfometrijska opažanja visine presadnice i broja listova. Po završetku uzgoja presadnica utvrđena je masa podzemnog i nadzemnog dijela biljke te sadržaj suhe tvari u biljnim djelovima. Učinak primijenjenih biostimulatora je varirao ovisno o roku sjetve i promatranom svojstvu. U pojedinim slučajevima je pozitivan učinak izostao tako da su najveće vrijednosti utvrđene kod netretiranih presadnica, ili nisu utvrđene značajne razlike između tretmana i kontrole. Osim biostimulatora, na rast i razvoj presadnica utječu i mikroklimatski uvjeti zaštićenog prostora, što se očituje u trajanju proizvodnog ciklusa. Uzgoj presadnica trajao je od 42 dana za rok sjetve 30. ožujka do 55 dana za rok sjetve 26. veljače. Obzirom na trajanje uzgoja presadnica i pozitivno djelovanje biostimulatora, može se preporučiti rok sjetve 30. ožujka, uz 3 tretiranja presadnica biostimulatorom Bio-Plantella super F tijekom perioda od pikiranja do sadnje, u koncentraciji 0,15 %.Cultivation of tomato seedlings in the winter-spring period takes quite a lot (70-90 days), causing high costs of heating, and production. By selecting the appropriate date of sowing and applying a growth improver the period of breeding can be shortened. The goal of this study was to determine the effect of selected growth enhancers on growth of tomato seedlings in four different sowing dates, compared to untreated seedlings. The study was conducted in a heated greenhouse of the Vegetable Crops Department at the Faculty of Agriculture, University of Zagreb. The seeds of a tomato cv. 'Rutgers' were sown in polystyrene containers with 104 pots on four sowing dates (26 February, 9, 19 and 30 March 2015). Immediately after pricking and twice more in between of 10-12 days seedlings were treated with foliar growth enhancers Bio-Plantella super F and Ekorast, in concentration of 0.15%. During each treatment, morphometric observations regarding the seedlings’ height and number of leaves were performed. After completion of the cultivation of seedlings, the mass of underground and above-ground part of the plant as well as the content of dry matter in the plant parts were determined. The effect of applied bio-stimulant varied depending on the planting date and the observed characteristics. In some cases the positive effect was absent, so the maximum values were therefore determined in untreated seedlings or, on the other hand, it showed to be no significant difference regarding the treatment and control. Besides biostimulant, the growth and the development of seedlings is affected by the microclimate conditions of the greenhouse, which becomes noticable in the duration of the production cycle. Growing of the seedlings lasted for 42 days for the sowing date of 30 March and, in comparison, 55 days for the sowing date of 26 February. In accordance to the time needed for growing seedlings and the positive affect of biostimulants, the sowing date of 30 March can be recommended, combined with three treatments of a biostimulant Bio-Plantella super F (at a concentration of 0.15 %) over a period from pricking to planting