Supplementary Table 1 Primers used to amplify cDNA sequence of the Wx gene

Primer name / Primer sequence / Amplified region / Position2)
Forward primer (5'→3') / Reverse primer (5'→3') / From / To
Wx1 / CTTTGTCTATCTCAAGACAC1) / CTGGCAAAGAAGGCTGAAAC / exon 1–exon 5 / 163) / 1061
Wx2 / TGCAGAGATCTTCCACAGCA / CACGCTTGTAGCAATGGAAA / exon 2–exon 4 / 416 / 927
Wx3 / ACCAGTACAAGGACGCTTGGG / ATGAGCTCCTCGGCGTAGTA / exon 3–exon 9 / 832 / 1441
Wx4 / TCCGAGAGGTTCAGGTCATC / CCCGGATACTTCTCCTCCAT / exon 8–exon 11 / 1299 / 1816
Wx5 / CCGCCAAGTACGACGCAAC / CCAGGCCCAGGAGCACAT / exon 9–exon 14 / 1558 / 2205
Wx6 / GAGAAGTATCCGGGCAAGGT / TGGCAATAAGCCACACACAT / exon 11–3' UTR4) / 1803 / 2481

1) This sequence was cited from Bligh et al. (1998)

2) The numbers refer to the nucleotide positions in rice Wx cDNA sequence (X62134)

3) This position is located in the first exon of the Wx gene, but is not included in the rice Wx cDNA sequence (X62134), and it is relative to the sequence order of the gene accession AF031162 (Lemont)

4) UTR indicates non-translated region

Supplementary Table 2 Correlations of the GBSS activities and the AAC of tested SSSLs during grain development in spring and fall seasons

Season / Correlative coefficient
6 DAF / 11 DAF / 16 DAF / 21 DAF / 26 DAF / Mean
Spring / 0.690** / 0.697** / 0.777** / 0.737** / 0.741** / 0.743**
Fall / 0.745** / 0.720** / 0.697** / 0.721** / 0.709** / 0.721**

DAF indicates days after flowering. ** shows the significance at the 0.01 probability level

Supplementary Table 3 Variation in AAC of SSSLs with different Wx alleles between the spring and fall seasons

Season / Air temperature (°C)1) / Wx allele / No. of materials / Mean value of AAC (%)2) / Paired t-test value3)
Max / Min / Spring / Fall
Spring / 33.3 / 26.2 / wx / 2 / 2.15 (0.15) / 2.23 (0.22) / 0.512 ns
Fall / 30.2 / 22.1 / Wxt / 3 / 12.25 (0.37) / 15.75 (0.35) / 5.22E-13***
Wxg1 / 8 / 21.93 (0.52) / 23.57 (0.52) / 1.58E-14***
Wxg2 / 2 / 24.47 (0.57) / 24.98 (0.52) / 0.136 ns
Wxg3 / 2 / 25.81 (0.48) / 26.19 (0.44) / 0.189 ns

1) Data were obtained from the Bureau of Meteorology of Guangdong Province. The maximum (Max) and minimum (Min) air temperatures are the average of maximum and minimum air temperatures, respectively, from heading to havest

2) Standard deviations are shown in parentheses

3) ns means no significance. *** shows the significance at the 0.001 probability level

Supplementary Table 4 Nucleotide polymorphic sites within the rice Wx gene detected in SSSLs with different Wx alleles

SSSL / (CT)n / Intron 1 / Exon 2 / Exon 6 / Exon 9 / Exon 10 / AAC class / Wx allele
W07-11-02-09-01 / 16 / T / d / A / T / C / Glutinous / wx
W17-10-07-05-12 / 17 / T / d / A / C / C / Glutinous / wx
W12-09-28-10-18-10-04 / 17 / T / - / A / C / C / Low / Wxt
W15-12-03-02-02-01 / 17 / T / - / A / C / C / Low / Wxt
W20-15-01-01-10 / 18 / T / - / A / T / C / Low / Wxt
W06-26-21-10-10 / 14 / G / - / C / T / C / Intermediate / Wxg1
W08-09-05-05-09 / 17 / G / - / C / C / C / Intermediate / Wxg1
W10-13-07-05-08-01 / 17 / G / - / C / T / C / Intermediate / Wxg1
W11-02-04-01-02-09 / 17 / G / - / C / T / C / Intermediate / Wxg1
W21-05-16-08-02 / 19 / G / - / C / T / C / Intermediate / Wxg1
W23-19-06-05-12 / 20 / G / - / C / T / C / Intermediate / Wxg1
W24-02-08-01-01-10-04 / 20 / G / - / C / T / C / Intermediate / Wxg1
W27-14-06-04-02 / 20 / G / - / C / T / C / Intermediate / Wxg1
W05-01-02-02-04-03-03 / 12 / G / - / A / C / T / High I / Wxg2
HJX74 / 11 / G / - / A / C / T / High I / Wxg2
W03-20-33-10-01-02 / 10 / G / - / A / C / C / High II / Wxg3
W04-10-02-07-10-03 / 10 / G / - / A / C / C / High II / Wxg3

The nucleotide polymorphisms positions are relative to the rice Wx cDNA sequence (X62134). ‘d’ and ‘-’ show 23-bp duplication and no 23-bp insertion at nucleotide positions 541-563 in exon 2, respectively