1. Fig. S1 The non-metric multi-dimensional scaling of 24 double haploid (DH) lines (colored in grey) in the background of 225 DH lines (colored in blue) of wheat Triticum aestivum varieties, Westonia and Kauz, based on 195 simple sequence repeat (SSR) markers and two Rht1-B1 and Rht2-D1 gene markers (2011). Points that are close together represent samples that are genetically similar, while points that are far apart are genetically divergent. In 2012, 21 DH lines were repeated. *W, Westonia; K, Kauz. Supporting Information Figs S1–S10 & Table S1

2. Fig. S2 Volumetric soil water content (v/v, %) at 10, 30 and 50 cm depth, respectively, in drought experiments at Merredin field station in 2011 and 2012. The average of the days after anthesis of all lines is presented. Closed circles, irrigated conditions; open circles, drought conditions. The vertical bars represent SE. Values with the same letter are statistically not different at P = 0.05.

3. Fig. S3 The average reduction in core phenotypes. Grain weight per main spike (GW), thousand grain weight (TGW) and seed number per main spike (KN) are shown in pooled selected double haploid (DH) lines and their parental lines (wheat Triticum aestivum varieties, Westonia and Kauz) under irrigated (closed bars) and drought (open bars) conditions at Merredin field station in 2011 and 2012. The vertical bars represent SE. Values with the different letter are significantly different at P = 0.05.

4. Fig. S4 The accumulation and degradation of stem WSC components in wheat Triticum aestivum variety, Kauz under drought and irrigated conditions from -4-41 d post anthesis (DPA). KD1-3, Kauz in three replicates under drought; KI1-3,Kauz in three replicates under well-watered conditions. 1, -4 DPA; 2, 3 DPA; 3, 11 DPA; 4, 17 DPA; 5, 25 DPA; 6, 31 DPA; 7, 41 DPA.

5. Fig. S5 The patterns of stem (sheath included) sucrose (a) and glucose (b) concentrations in wheat Triticum aestivum varieties, Westonia and Kauz under irrigated and drought conditions. The vertical bars represent SE. Values with the same letter are statistically not different at P = 0.05. (a) (b)

6. Fig. S6 The correlation of stem (sheath included) bifurcose concentration and 1-FEH enzyme activities between 0-35 DPA (a) and 6-kestose concentrations and 6-FEH activities between 15-45 DPA (b) in wheat Triticum aestivum varieties, Westonia (circles) and Kauz (diamonds), respectively, under irrigated and drought conditions. (a) (b)

7. Fig. S7 The fragments of 1-FEH w3 were amplified from wheat Triticum aestivum varieties, Westonia and Kauz with an upstream primer pair (FEH2F/FEHw3R, a), a downstream primer pair (FEHw3F/FEH2151R, b), and a 3’terminal primer pair (FEH4690F/6BPR, c). Nulli-tetra lines (N6AT6D, N6BT6A, N6DT6B) from wheat T. aestivum varieties, Chinese Spring were used for confirming the fragment location. Chinese Spring was used as a positive control and ck as a negative control. M, standard marker.

8. Fig. S8 The promoter region amplification of 1-FEH w3. (a) 1-FEH genes isolated from bread wheat chromosomes 6A, 6B and 6D (Zhang et al., 2008). The primers used are indicated by arrows ( see also Table S1). (b) Amplification of the promoter region of 1-FEH w1 (6A) from wheat Triticum aestivum variety, Chinese Spring (CS) and nulli (N)-tetra (T) stocks of Chinese Spring (N6AT6D, N6BT6A, N6DT6B). Absence of amplification in N6AT6D indicates that the primer pair was specific for 1-FEH w1 on the 6A chromosomes. (c) Amplification of the promoter region of 1-FEH w3 on 6B using wheat Triticum aestivum L. varieties, Westonia and Kauz and (d) on the nulli-tetra lines of N6AT6D, N6BT6A and N6DT6B. The results indicate that the amplified fragment originates from chromosome 6B. ck, negative control; M, standard marker.

9. Fig. S9 The QTL location of height, thousand grain weight (TGW) and peduncle proportion detected on 6B in the genetic linkage map of the 225 DH population of wheat Triticum aestivum varieties, Westonia/Kauz. Mapped markers are indicated on the right and their corresponding genetic distances (cM) are indicated on the left. Quantitative trait loci (QTL) confidence interval with an F-value over the threshold is by vertical bar.

10. Fig. S10 Evolution of stem (sheath included) 6-kestose concentrations (a) and 6-FEH activities (b) in wheat Triticum aestivum varieties, Westonia and Kauz under irrigated and drought conditions. The vertical bars represent SE. Values with the same letter are statistically not different at P = 0.05.

11. References Zhang J, Huang S, Fosu-Nyarko J, Dell B, McNeil M, Waters I, Moolhuijzen P, Conocono E, Appels R. 2008. The genome structure of the 1-FEH genes in wheat (Triticum aestivum L.): new markers to track stem carbohydrates and grain filling QTLs in breeding. Molecular Breeding 22(3): 339-351.