Data on root system architecture of water efficient maize as affected by different nitrogen fertilizer rates and plant density

Root system architecture is a resource with untapped potential for agricultural improvements. The presented data describes the root system architecture of water efficient maize lines to different nitrogen fertilizer rates and plant density at two locations in North West Province of South Africa. The experiment was carried out during the 2015/16 and 2016/17 planting seasons. The root system architecture traits brace root angle, brace root number, brace root branch depth, crown root angle, crown root number, crown root branch depth and number of lateral roots were scored with the aid of shovelomics score board. ANOVA was used to analyze the data set and means separated with DMRT (p ≤ 0.05).The regression analysis was used to determine the relationship among nitrogen fertilizer and root architecture system.


Specifications table
Agricultural and Biological Science: Agronomy and Crop Science Specific subject area Plant physiology, plant biology, plant breeding, crop nutrition and soil fertility Type of data Table  Figure How data were acquired Root system architecture were assess using shovelomics score board Data format Raw data Parameters for data collection Root system architecture was assessed at tasseling and physiological maturity stages using two uprooted plants from the based at 30 cm in each plot. The root system architecture traits brace root angle, brace root number, brace root branch depth, crown root angle, crown root number, crown root branch depth and number of lateral roots were scored with the aid of shovelomics score board. Description of data collection

Value of the data
• The data showed the effect of different nitrogen fertilizer rates and plant density on root system architecture • The data revealed the effect of soil types of each location on root system architecture.
• The data indicated the effect of interaction of nitrogen fertilizer rates, plant densities and locations on root system architecture. • The data can be used by plant physiologist, plant breeders, crop nutritionist and general agronomist.

Data description
The data describes the root system architecture of water efficient maize as affected by different nitrogen fertilizer rates and plant density in two locations of North West Province of South Africa. The experiment was carried out during 2015/16 and 2016/17 planting seasons. The meteorological data of experimental locations ( Table 1 ). Tables 2 -4 shows effect of each treatment factors (location, plant density and nitrogen fertilizer rates) on root system architectural trait.   The interaction effect of location, plant densities and nitrogen fertilizer rates on root system architectural trait is presented in Tables 5 and 6 . Table 7 presents relationship between architectural root system traits and grain yield. Fig. 1a -e presents relationship between N rates and root system architectural trait.

Description of study area
The experiment was carried out at the Molelwane, North-West University (NWU) Research Farm (25 °48 1 S, 45 °38 1 E.; 1012 m asl) and Taung Experimental Station (27 30 1 S, 24 30 1 E;  ,555, respectively. The fertilizer application treatment was carried out by applying a third of the each rate as basal treatment at planting using NPK 20:7:3 while two-third and a third of the remaining quantity from each rate was applied as top dressing at 3 and 5 weeks after sowing (WAS) using lime ammonium nitrate (LAN, 28%).Weeding was done manually at 3 and 7 weeks after sowing.

Assessment of root system architecture
Root system architecture was assessed at the tasseling and physiological maturity stages using two uprooted plants from the based at 30 cm in each plot. A manually designed shovelomics score board was used to score the root architecture as described by Trachsel et al. [2] . Root system architectural traits assessed include brace root, crown root and lateral root with focus on the number, branching angle and depth. Root depths were classified as shallow or deep/steep. Root with 0-5 cm depth was classified as shallow while that within 5-10 cm depth was classified as deep/steep as described by Trachsel et al. [2] . Classification of brace and crown angle was 10-50 °as shallow and 50-90 °as deep and steep while assessment of root number was by counting using the standard procedure described by Trachsel et al. [2] . Grain yield of WEMA maize was obtained as described by Adebayo [1] .

Statistical analysis
All data obtained were subjected to analysis of variance (ANOVA) using the GenStat 11th edition. Differences between the treatment means were separated using Duncan Multiple Range Test (DMRT) test at 5% level of probability. Regression was used to estimate relationship between N rates grain yield and root system architectural trait using Excel program.