Effects of row spacing on leaf area index (LAI) of two spike types of wheat under high plant density over a two-year period (2011 and 2012).

<p>R₀, R₁, R₂ and R₃ refer to 5-cm row spacing, 15-cm row spacing, 25-cm row spacing and 35-cm row spacing, respectively. The data are means ± standard error (SE; n = 3). Different small letters in each group indicate significant differences at <i>P</i><0.05.