**2.2 Measurement of agronomic traits and hardness index**

Before harvesting, ten plants of each genotype were randomly selected in each plot to determine spikelet number per plant, flag leaf length and flag leaf width, as well as flag leaf area calculated from the product of leaf length and maximum leaf width × 0.75. Grains per spike, grain weight per plant and grain weight per spike were determined after harvesting. Kernel hardness, grain diameter and thousand-kernel weight were measured on 300-kernel samples of each genotype using the Perten Single Kernel Characterization System (SKCS) 4100, following the manufacturer's operation procedure (Perten Instruments North America Inc., Springfield, IL). Mean, standard deviation, and distribution of SKCS hardness data were used to classify the genotypes tested into soft, mixed, and hard types.
