Development of techniques for accelerated propagation of perspective citrus rootstocks for protected ground using green cuttings

Relevance. Currently, citrus crops occupy a leading position in the world in terms of production. An alternative to industrial cultivation of citrus fruits in open ground can be intensive cultivation technologies in protected ground, for which it is important to develop methods for accelerated production of planting material. Therefore, the aim of our research was to identify the optimal components of the mixture of IBA and IAA wetting powder for the accelerated propagation of green cuttings of promising citrus rootstocks grown year-round in protected ground conditions. Methods. Green cuttings of citrus rootstocks citrumelo (C. trifoliate (L.) Raf × C. paradise Mcf), citrus volkameriana (C. volkameriana Ten. & Pasq), and citrus macrophylla (C. macrophylla Wester) were treated with experimental mixtures of root formation stimulants IBA (indolyl-3-butyric acid) and IAA (indole-3-acetic acid) corresponding to the experimental variants ( IBA 0.5 % (control); IAA 1.0 %; IBA 0.5 % + IAA 0.5 %; IBA 0.5% + IAA 1.0 %; IBA 1.0 % + IAA 0.5 %; IBA 1.0 % + IAA 1.0 %) and planted in cassettes with substrate, after which they were rooted in a film tunnel with a fogging unit, at a humidity of 85-90 % and a temperature of +20...+25 °C. Results. During propagation of the rootstocks under study, a species-specific reaction to the techniques being developed was observed. For the treatment of green cuttings before planting for rooting, it is effective to use a wettable powder with different component compositions of IBA and IAA for each rootstock: for C. trifoliata × C. paradisi, a mixture of IBA 1.0 % + IAA 1.0 %; C. volkameriana – a mixture of IBA 1.0 % + IAA 0.5 %, for C. macrophylla a mixture of IBA 0.5 % + IAA 0.5 %. Conclusion. Based on the results obtained, the use of optimal components of the composition allows not only to achieve maximum rooting rates of green cuttings (66.7-100 %), but also to obtain reliable differences in the number and total length of roots.