The effect of the physiological analogues of auxin, the compounds TA-12 and TA-14, on the apex development, growth, winterhardiness and productivity formation of the winter oilseed rape var. ‘Casino’ was studied. Field experiments were carried out in 2002–2004 at the experimental station of the Lithuanian Institute of Agriculture, Dotnuva-Akademija. The results showed a positive effect of the compounds TA-12 (2·10^-3 M) and TA-14 (4·10^-3 M) on the autumnal development of oilseed rape plants and their preparation for overwintering: they stimulated the conversion of the apex vegetative phase into a generative one, promoted flower formation and further development, intensified monosaccharide accumulation in the root collum, and improved the winterhardiness of this culture. In test variants, the number of perished plants was lower than in the control. Data of our research demonstrated the functional involvement of sugars in the cold acclimation process of oilseed rape.

Application of compounds TA-12 (417 g ha^-1) and TA-14 (369 g ha^-1) to plants in autumn at the 4^th–5^th leaf formation stage not only enhanced winterhardiness but also influenced the further growth in spring and formation of yield components. Under the effect of the compounds TA-12 and TA-14 the number of siliguae on the main and lateral branches racemes and their seed mass increased. All these factors contributed to an extra seed yield by 0.45 and TA-14 by 0.64 t ha^-1, respectively, the control yield being 3.53 t ha^-1.