A Novel Method for Phenotyping Root Angle of Cereal Crops

Cereals are the major components of human diet. To meet the food demand by 2050, the rate of yield gain in cereals must be 2.4%, while the current gain is about 1%. Further, abiotic stresses such as drought stress hinder the productivity of cereals. Root system plays a vital role in overall productivity of crops especially under abiotic stresses and in direct seeded resource conservation technologies of cereals. Among the component traits of root architecture, root angle plays important role in determining the deep rooting, which in turn associated with drought stress tolerance. Root angle is a dynamic trait regulated by external as well as internal factors. Wide variability has been reported for root angle in cereals. This genetic variability was not utilized to great extent due to the phenotyping bottlenecks. Although, many methods are available, these methods are expensive, complicated and time consuming. So, an easy cheap and robust method was needed to screen large number of genotypes. Here we have developed a novel method to measure root angle which is easy, robust, cheaper, and does not require special training and equipments. Using this method, we phenotyped 29 rice genotypes and 55 wheat genotypes under field conditions. The result indicates that medium root angles (30^o -60^o) have highest variability among genotypes. The developed method captured the variability accurately and wide variability was found among genotypes for root angle in both rice and wheat.