Influence of High Temperature on Root System Architecture Traits in Sunflower (Helianthus Annuus L.) Genotypes

Roots grown in plant growth chambers annexed with image analysis could be potent for screening root traits to understand their morphology and architecture prior to field experimentation.The experiment was carried out to study the effect of increasing temperature (25, 30, 32.5, 35, 37.5 and 40°C) on germination and root parameters of 10 inbred lines and 4 hybrids of sunflower during a seven day period.The objective of the study was to investigate the effect of increasing temperature on root traits so that the breeding programme may be benefited.The root traits studied include root length, projected area, surface area, root volume, root average diameter, root dry weight of sunflower lines.Sampling was done and the data was recorded by using win RHIZO software.Analysis of data revealed that there was a significant difference between genotypes and treatments for the characters under study.The average root diameter was highest at 40°C.Primary root growth, projected area, surface root area and root dry weight averaged over all genotypes was greatest in the 30 -32.5°C temperature range whereas, root volume was high at 30°C and maximum germination percentage was observed at 25°C.Hybrids DRSH-1 and CSFH-12205 and CMS Lines -127B, 70B, 42B, AKSF-6-3B showed better germination and root traits at high temperatures (HT).The relationship between sunflower root growth and temperature may be of value in determining planting dates and the root traits studied could be indicators of high temperature tolerance.