Evaluation of Root Traits at the Seeding Stage Using Rhizobox System

Studying and observing the distribution of roots as the ‘hidden half’ is very complicated because it requires an appropriate method and an understanding of the significant influences of the environment on the root growth. The root system is recognized as having a relationship with the crop productivity, thus can be optimized to increase crop productivity, particularly for growth under low input condition involving unevenly distributed water and nutrient surrounding the rhizosphere. The aim of this study is to evaluate the root growth in the seeding stage and QTL analysis using the Rhizobox system. In this study, ninety-three recombinant inbred lines originated from a cross between Peking and Tamahomare (PT-RILs) were used to identify for the QTL analysis. The seed of the soybean is planted in germination paper in the Rhizobox system for six days. Root parameters are the number of roots, root length, root growth angle (measured from the vertical axis by using software Image J), root width, and root depth. The results showed that for all traits, the PT RILs population exhibited a broad and continuous distribution of values ranging between the values of the parental cultivar. A total of nine putative QTLs were identified for the eight of the nine tested traits. No significant QTLs for root growth angle was detected. The phenotypic variation explained by each QTL range 14-21 %. In terms of root surface area, two major QTL was located on Chr.9 and Chr.19 for root width and root depth. Meanwhile QTLs for root length was located on Chr.8 and Chr.11