The total length of the root system was sensitive to changes in traits regulating the number of lateral branches a given root order can produce (the inter-branch distance, the maximum length of root and its apical non-branching distance) and the elongation rate of main axes.
For example Shrestha et al. (2014) report that rhizotron screens rank subgroups in the order aus > tropical japonica > indica ≈ temperate japonica for maximum root length which was in agreement with an earlier report of Lafitte et al. (2001).
Seedling roots were sorted and classified by root order (first sixth order roots).
We extracted information from 24 published papers on QTLs controlling 29 root parameters including root number, maximum root length, root thickness, root/shoot ratio, and root penetration index.
Below-ground growth measurements included maximum root depth and maximum root spread, hereafter referred to as root depth and root spread.
The maximum root zone storage is calculated considering the distribution of land cover and rooting depth.
According to their report, many QTLs for the weight of deep roots, maximum root length, root thickness, and root dry weight were located in the DRO3 region.
QTL for root to shoot ratio (R/S, violet), root number (RN, green) maximum root length (MRL, red), and root thickness (THK, blue).
As expected, mean root diameter increased with increasing root order (Fig. 2b).
The cumulative root length decreased sharply with increasing root order (Fig. 2a).
