Fig. 2: GS3.1 is a QTL that controls the grain size by influencing cell expansion.

a Mature grains of NIL-GS3.1^HJX and NIL-GS3.1^HP. Scale bar =1 cm. Comparison of 1000-grain weight (b), grain length (c), grain width (d), tiller number (e), spikelet number (f), yield per plant (g) and yield per panicle (h) between NIL-GS3.1^HJX and NIL-GS3.1^HP (n = 30 plants). i Comparison of plot yield between NIL-GS3.1^HJX and NIL-GS3.1^HP (n = 3 plots, about 2 square meters per plot). j Time-course of the change in caryopsis wet weight and dry weight for NIL-GS3.1^HJX and NIL-GS3.1^HP (n = 3 plants, ≥20 caryopses per plant). k Scanning electron micrographs of the outer epidermal cells of spikelet hulls just before heading. Scale bar =1 mm. The red rectangle border shows the area for measuring the cell length. Comparison of the outer epidermal cell length (l) and cell number in the grain-length direction (m) between NIL-GS3.1^HJX and NIL-GS3.1^HP (n = 24 spikelet hulls, 10 cells per spikelet hull for cell length measuring). n Micrographs of the cross-section of spikelet hulls just before heading in the grain width direction. Scale bar = 1 mm. The red rectangle border shows the area used for measuring the cell width. Comparison of the outer epidermal cell width (o) and cell number in the grain-width direction (p) between NIL-GS3.1^HJX and NIL-GS3.1^HP (n ≥ 3 spikelet hulls, n = 45 cells). The values in b–h, j, l, m, o, p represent the mean ± s.d. *P < 0.05 and **P < 0.01 indicate significant differences compared with NIL-GS3.1^HJX in two-tailed Student’s t-tests. The values in i represent the mean ± s.d.. *P < 0.1 indicate significant differences compared to NIL-GS3.1^HJX in two-tailed Student’s t tests. The source data underlying Fig. 2b–j, l, m, o and p are provided as Source data file.