The Evaluation of Growth Indices in Different Irrigation Systems and Weed Control Treatments and Correlation of Quantitative and Qualitative Traits of Sugarcane (Saccharum officinarum)

In order to evaluate the growth indices of sugarcane in different irrigation systems, weed control treatments and correlative associations with quantitative and qualitative traits of sugarcane, an experiment was conducted as split plot based on randomized complete block design (RCBD) with three replications in 2020 at Sugarcane Development Research and Training Institute of Khuzestan, Ahwaz, Iran. The five irrigation systems were surface irrigation, subsurface irrigation with a flow rate of 2.3 L/hour, subsurface irrigation with a flow rate of 3.6 L/hour, sprinkler irrigation and furrow or conventional irrigation as the main plot and weed control treatments were (weed interference (no weeds control) throughout the season (Weedy treatment), weed control in total period of season (weed free treatment) and cultivation (twice) as the subplot. The highest crop growth rate (CGR), dry matter and height were observed in sprinkler and subsurface irrigation with a flow rate of 3.6 L/hour and the lowest in furrow irrigation. Growing degree day (GDD) required to reach 50% of dry matter were determined for sprinkler irrigation (1894), subsurface irrigation with flow rate of 3.6 L/hour (1762), subsurface irrigation with flow rate of 2.3 L/hour (1538), surface irrigation (1494) and furrow irrigation (1474 degrees of growth day). Also, growth indices in weedy treatment was lower than the both treatments weed free and cultivation. Correlation analyses indicated that sugarcane quality traits were not closely associated with growth indices and sugarcane quantitative traits. However, a positive correlation was observed between quantitative traits of sugarcane such as height, internode length, number of internodes, cane yield, sugar yield, dry matter and crop growth rate and a negative correlation was observed between cane yield with stem diameter and weeds biomass. According to the results, both systems of sprinkler irrigation and subsurface irrigation with a flow rate of 3.6 L/hour seem to be suitable for sugarcane production in Khuzestan in the first ratoon.