Impact of Cutting Place Using Seradix 3 Powder and Planting Growth Media on Ability Growth of Some Root Characteristics for Populus euphratica L.

Poplar is the most economically important tree species in Iraq and other countries in Asia. Identification cutting places for root traits and selecting suitable planting media may be linked to the application of growth regulator (Seradix 3 powder) which could enhance the growth potential roots of the cuttings in breeding programme. However, there is limited information available on the combined effects on specific root characteristics of poplar seedlings. To this end, two types of cuttings (basal and intermediate) were treated with Seradix 3 (0.8% IBA) powder and a control (no hormone), and three planting media (sand, loam, and mixed (sand and loam 1:1)) were included in this study, which began in mid-December 2018 until the end of March 2019 in a greenhouse at the Department of Horticultural/Faculty of Agriculture/Tikrit University. The study was designed as a factorial experiment according to the randomized complete block design (RCBD) in three replications; the means were compared according to Duncan’s multiple range test (P≤0.05). Rooting percentage, root length, number of first-order (lateral roots), fresh and dry weight of root systems were recorded at the end of this study. The results showed that the basal cuttings had significantly higher values compared to intermediate cuttings in all root parameters. Seradix 3 powder revealed a highly significant impact on all evaluated root parameters compared to control. Interaction of (basal cuttings (C1) + Seradix 3 (S1)) revealed gave optimal results and optimal conditions for root development. As well, the combination of (basal cutting (C1) + sand growth media (M1)) provides the most favorable conditions for robust root development. Also, the interactions of (C1 + S1 + M1) gave optimal findings compared to intermediate cuttings treated and control (untreated), these findings might help to improve and develop the growth potential of Populus in breeding programme.