Figure 5

Means for morphometric variables. A) Mean ovule curvature, ovule area, and percentage ovule area occupied by integument, nucellus and germline (meiocyte or young embryo sac) for 115 diploid S. bicolor genotypes (population mean, ±SD) and for four groups of these genotypes partitioned by k-means clustering based on frequency of aposporous embryo sac (AES) formation (AES cluster, ±SE). Measurements were taken at the dyad through early tetrad (M) and the 1-nucleate embryo sac (ES1) stages. k-means clusters representing genotypes with the fewest, few, more and most AES consisted of 89, 15, 8 and 3 genotypes, respectively (see Additional file 6 for ANOVA results). B) Mean ovule curvature for 300 F₂ S. bicolor genotypes (±SD) and for four groups of the F₂ (±SE) partitioned by k-means clustering based on frequency AES formation. Measurements were taken at the M, ES1, and early 8-nucleate embryo sac (ES8) stages. k-means clusters representing F₂ with the fewest, few, more and most AES consisted of 177, 89, 25 and 9 genotypes, respectively (see Additional file 7 for ANOVA results). C) Population (±SD) and cluster group (±SE) means based on 119 S. bicolor recombinant inbred lines (RIL). RIL were partitioned by k-means clustering based on frequency of AI or AES per genotype (top graphs). k-means clusters representing RIL with few, more and most AI or AES consisted of 81, 30 and 8 RIL or 76, 37 and 6 RIL, respectively. RIL were also partitioned by k-means clustering based on ovule curvature at the M and ES1 stages (bottom graphs). k-means clusters representing RIL with low, moderate and high ovule curvature angles at M or ES1 consisted of 49, 49 and 21 RIL or 19, 49 and 51 RIL, respectively (see Additional file 8 for ANOVA results).