Rose rootstocks position and auxins affect grafting take of ‘Inca’

Abstract

Inadequate grafting take of some of the rose cultivars may cause economic losses. The study was conducted to determine the effects of cutting position (top, middle and bottom) of Rosa hybrida rootstocks (‘Natal Briar’ and ‘Rosa Progress’) and auxins (0 %, 0.4 % IBA and 0.2 % NAA) on rooting and grafting take of rose cultivar ‘Inca’. Changes in endogenous carbohydrate content during rooting were measured on days 0, 3 and 7 after sticking. The experiment was factorial in a completely randomized design. Interaction between cutting position and rootstock was significant (P ≤ 0.05) for most of the parameters measured. The shoot height, root number, percent rooting and grafting take increased towards the basal position in ‘Rosa Progress’. In ‘Natal Briar’, the shoot and root growth parameters increased towards the top though non significant except grafting take that significantly increased towards the basal position. The auxin treated cuttings recorded significantly (P ≤ 0.05) higher grafting take and rooting percentage than the control. 0.4 % IBA exhibited higher shoot height, leaf number and root number than 0.2 % NAA. The rootstock ‘Natal Briar’ recorded significantly (P ≤ 0.05) higher rooting percentage and grafting take than ‘Rosa Progress’. Middle and top position cuttings of ‘Rosa Progress’ and ‘Natal Briar’ recorded higher carbohydrate content, respectively than bottom position cuttings. Bottom position recorded higher sucrose content on day 3 than days 0 and 7 after planting in ‘Rosa Progress’. ‘Natal Briar’ exhibited significantly (P ≤ 0.05) higher carbohydrate content than ‘Rosa Progress’. The increase in growth with top position cuttings of ‘Natal Briar’ could be attributed to high carbohydrate content. The high growth responses in bottom position cuttings of ‘Rosa Progress’ could be attributed to high sucrose content on day 3 after planting. The stem cuttings of rootstocks for top grafting rose cultivar ‘Inca’ should be taken from bottom position cuttings of both rootstocks, and auxins should be applied to increase rooting and grafting take.