Biological features of reproduction of clonal rootstocks of stone crops by green cuttings

In the intensification of the horticulture industry, the main role is assigned to clonal low-growing rootstocks. Green cuttings are the main method of propagation of clonal rootstocks of stone crops. The basis of green cutting technology is the biological ability of plants to regenerate. The technology of rooting green cuttings is based on the cultivation of whole plants from leafy stem cuttings due to the formation of new adventitious roots. The research was conducted at the Research Institute of Horticulture and Medicinal Plants «Zhigulevskie Sady» in the period from 2021 to 2023. Green cuttings of rootstock forms were planted in a greenhouse with an area of 18 m², coated with cellular polycarbonate. The microclimate in the greenhouse was maintained with the help of an ultrasonic fog-forming unit operating daily from 7 a.m. to 8 p.m. The object of the study was 10 clonal rootstock forms for cherries and cherries, including VSL-2 [Cherry BS-2 (R. frutikosa Pall.) × L-2 (P. lannesiana Wils.)], LC-52 (Lyubskaya × Cerapadus No. 1), TSH-32 (Cerapadus No. 1 × Black Consumer goods), groups of Logri rootstocks (Cherry-cherry Kalitvyanka × Chinese Dwarf cherry (P. pseudocerasus) under the following numbers: 61–72, 61–701, 61–70, 61–12, 61–740, 61–16, 61–718; 5 rootstock molds for plum and apricot – Best, Best-2 (Low Microfiche × Cherry plum (M. besseyi × P. cerasifera), BBA-1 (Felt microfiche (P. tomentosa Thunb.) × Cherry plum (P. cerasifera Ehrh.), VPK-1 [(Low Microfiche × Karzinskaya Plum (M. besseyi × (P. nigra × P. americana)] and Eureka 99 [Vishnesliva Sapa (P. pumila L. × P. salicina Lindl) × cherry plum Excellent student (P. cerasifera Ehrh.)]. To increase the percentage of rooting, cuttings were pretreated with root formation stimulants. Cuttings were soaked in an aqueous solution of Kornevin (0,6 g/l) or Heteroauxin (100 mg/l) for 16–18 hours before planting to increase rooting. Rooting of green cuttings of clonal rootstocks of fruit crops was carried out in a greenhouse at an air temperature of +30…+35°C, almost 100% relative humidity, and a soil temperature of +25…+30°C. Green cuttings were planted in a greenhouse in a substrate according to the scheme 7 × 5 cm to a depth of 2–3 cm. With this planting scheme, up to 280 cuttings were planted per 1 m². The optimal cuttings period, treatment of cuttings with root formation stimulants, creation of a nutrient substrate with good water-physical properties in the greenhouse, uninterrupted operation of the fog-forming plant, carrying out leaf fertilizing ensured high yield, growth and development of rooted plants per unit area. The best result of rooting green cuttings was shown by clonal cherry rootstocks from the Logri family (Horse mane) – 61–72, 61–718, 61–740, 61–16 (85,0%, 87,0%, 89,7% and 90,0% respectively); plums VVA-1 – 80,0% and Best-2 – 82,9%. The lowest percentage of the yield of rooted plants was obtained from cherry rootstocks TSH-32 – 46,4%, plum rootstocks Eureka 99 – 57,1% and VPK-1 – 31,6%.