Rooting of blackberry (Rubus fruticosus L.) hardwood cuttings as influenced by cutting time and cutting length

This study was carried out during 2021-2022, in the Department of Horticulture, College of Agricultural Engineering Sciences, University of Sulaimani, Sulaymaniyah, Kurdistan Region-Iraq, to find out the effects of cutting time (T1: Mid-Nov., T2: Mid-Dec., T3: Mid-Jan., and T4: Mid-Feb.), cutting length (L1: 10 cm and L2: 20 cm), and their interactions on rooting and some growth parameters of blackberry Rubus fruticosus L. hardwood cuttings. The local blackberry cuttings were transplanted in a low tunnel greenhouse at Zarrayen, Sulaymaniyah governorate. Plastic pots of 28 cm radius x 26 cm height, containing a substrate (peat moss: perlite: builder’s sand with a 1:1:1 v/v ratio) were used, and 6 cuttings were planted as a replicate out of three replicates. The experimental design was laid out in a factorial complete randomized design (CRD), the data were subjected to the Analysis of Variance (ANOVA), and the means were separated by Duncan’s multiple range test (P≤0.05). After 90 days, the results showed that T1 was significantly superior in rooting (95.83%), shoot dry weight (2.03 g), shoot length (24.68 cm), and average leaf area (2.22 cm2). L2 cuttings recorded the highest significant values of rooting (96.87%), shoot dry weight (1.83 g), root dry weight (0.56 g), shoot length (25.49 cm), number of lateral branches per cutting (18.52), and average leaf area (2.19 cm2). The interaction (T1+L2) was significantly superior in rooting (98.61%), shoot dry weight (3.02 g), shoot length (28.41 cm), root length (51.04 cm), and average leaf area (2.47 cm2)