Comparison of the formulations of benzolinone on the yield and quality of potatoes (Solanum tuberosum L.)

Benzolinone is active substance of plant growth regulator Rastim 30 DKV wit h a wide spectrum of biological effects. The influence of two different fin al formulations of benzolinone in the potatoes (Solanum tuberosum L.) varie ties Albina, Svatava and Karin in the small plot trials was studied. Experi mental treatments were realized in Slovak and Czech Republic. The effect of dispersable concentrate (DKV) containing 300 g and emulsiable concentrate (EK) containing 50 g active substance per liter was compared. Split applica tions of formulations consisting of dipping of seed tubers in 0.003 and 0.0 18% benzolinone solutions and of following foliar applications at the stage of flower buds in doses 100 and 600 ml.ha(-1) in 400 to 444 liters of wate r per ha were used. The formulations were evaluated on field emergence rate , number and weight tubers per hill, yield, starch content and nitrate cont ent. Both formulations as DKV as EK have significantly increased number and weight of tuber under the hill mainly tubers of the middle consuming size category (Fig. 1) of three varieties and all localities (Tabs. I to IV). Nu mber of tubers has increased from 11.5 to 34.7% (EK) and from 10.0 to 36.7% (DKV) over the control. Weight of tubers has increased from 7.8 to 32.2% ( EK) and from 4.05 to 44.6% (DKV) over the control. Yield has significantly increased in average from 7.9 to 14.8% only by cv. Albina (Tabs. I, IV, V). Starch content was a little but insignificantly increased (Tabs. I to IV). Nitrate content has significantly decreased only by cv. Albina from 22.0 t o 30.3% under control (Tabs. I, IV, V). Emulsiable formulation inhibited th e field emergence rate and had phytotoxic effect on the leaves (Fig. 2). Th e most sensitive variety was Svatava and the less one Albina. The best biol ogical effect with benzolinone formulations on the quantitative and qualita tive parameters was reached without fertilization (Tab. IV). On the base of these results was proposed Rastim 30 DKV into state verification tests in order to extend its registration for potatoes.