Evaluation of Root Characteristics in Grain Sorghum¹

Abstract

Abstract Breeding for drought resistance has been limited by the lack of a simple method of screening. Observations in the field cannot be made regularly, nor can the condition be repeated. A laboratory method of testing for drought resistance was needed. To investigate techniques, 10 cultivars of sorghum, Sorghum bicolor (L.) Moench, were planted in washed sand in plastic plots in a growth chamber. Five plants in each pot were fed a nutrient solution for 3 weeks. When they were harvested, wet root weight, root length, root volume, and root/shoot ratio were determined. The purpose of this study was to evaluate the root characteristics among 10 sorghum cultivars known to vary for drought resistance. Significant varietal differences for all characters were found. In general the most drought‐resistant cultivars had heavier root weight, greater root volume, and higher root/shoot ratios. This technique shows promise for identifying drought‐resistant lines, but it involved a considerable amount of time and labor. Root weight would probably be the most indicative and easiest characteristic to determine.