Root traits and root distribution patterns in advance sugarcane clones under early drought stress conditions

Abstract

Root system is an important mechanism of drought resistance. The ability of sugarcane genotypes with good root system to enhance nutrients and water uptake for plant growth resulted in high yield. The objectives of this study were to (1) evaluate growth patterns of root parameters and physiological responses and (2) determine the relationships between root traits and physiological traits in 15 advance sugarcane clones under early drought stress and recovery condition. Root traits of 15 sugarcane genotypes were evaluated in rhizobox under greenhouse conditions at Faculty of Agriculture, Khon Kaen University, Thailand. Water deficit was imposed during early growth stage from 16 to 75 days after planting (DAP) followed by re-watering was applied to the crop at field capacity (FC) moisture level from 76 until 90 DAP. Relative water content (RWC) and SPAD chlorophyll meter reading (SCMR) were collected at 60 and 90 DAP. Root length, root volume and biomass were recorded at 90 DAP and then root:shoot ratio and water use efficiency (WUE) were calculated. Root distribution patterns differed among sugarcane genotypes and were classified into 5 groups based on root length. Sugarcane genotypes with high roots length in the upper and lower soil layers are Kps01-4-29, Kps07-17-83 and LK92-11, and root volume and root:shoot ratio of these genotypes was moderate to high. The high rooting genotypes could maintain high RWC and SCMR during drought and re-watering periods and resulted in high biomass and WUE. The information obtained for this study will be useful for sugarcane breeding for drought resistance.