Synergistic Effects of Low Tunnel Polyethylene Covering and Silicon Spraying on Growth and Yield of Two Radish Varieties under Cold Stress

A field experiment was conducted on one of the private sector farms in Albuhidari area located in Al-Najaf governorate, Iraq, during the autumn season of 2021. The current research aimed to investigate the influence of polyethylene covering integrated with potassium silicate (K₂SiO₃) spray on the growth and yield of radishes. A split split-plot system was implemented based on RCBD with three replicates. The field plots were divided into two groups (non-covered plots and covered with low tunnel polyethylene sheets) designated as the main plots. While the two varieties of local radish (white and red) were assigned as subplots, and three concentrations of (K₂SiO₃) (0, 400, 600 mg.L^-1) were assigned as sub-subplots. ANOVA results demonstrated that the main effect of each factor improved radish studied indicators for plant height, number of leaves per plant, leaf dry matter%, root dry matter%, and the root yield per plant. The polyethylene covering provided a physical barrier against cold stress, while the silicon treatments at high concentrations enhanced the plants’ tolerance to low temperatures and improved overall plant growth. Bi-interaction effects were almost significant for some indicators. Moreover, the triple interaction (polyethylene covering + red variety + spray with (K₂SiO₃) @ 600 mg.L^-1) was superior in all indicators except for root dry matter%. The results indicate that polyethylene covering combined with silicon treatments have a significant protective effect on white and red radish plants.