Fig. 3.

Frequency distribution of the root hair density of contrasting root hair genotypes grown in the field in sandy loam and clay loam soils for two subsequent years: 2017 (A–D) and 2018 (E–L). Samples were classified into five categories based on the approximate number of root hairs per millimetre: bald, 0–7 root hairs mm^–1; sparse, 7–15 root hairs mm^–1; moderate, 15–35 root hairs mm^–1; thick: 35–50 root hairs mm^–1; and dense: ≥50 root hairs mm^–1. Two sampling campaigns were done in 2017 at 24 and 56 d from sowing; and four sampling campaigns were done in 2018 at 19, 33, 49 and 61 d from sowing. Identical letters indicate no significant differences as tested using one-way ANOVA followed by a post-hoc Tukey’s test. NRH represents the no root hair genotype; BRH, the bud root hair genotype; SRH, the short root hair genotype; and WT, the wild type, all in the ‘Optic’ background, together with ‘Sassy’.