Fig. 1.
Fig. 1.

Comparison of the shattering among Jiucaiqing, IR26, and chromosome segment substitution lines (CSSLs). (a) Comparison of the shattering with a touch of the hand between Jiucaiqing and IR26 at 35 d after heading; (b) Comparison of the breaking tensile strength (BTS) between Jiucaiqing and IR26 at 0, 7, 14, 21, 28, and 35 d after heading; (c) Comparison of the shattering in CSSLs at 35 d after heading among 2014 and 2015; (d) Comparison of the temperature during seed development among 2014 and 2015. The unit of BTS, gf, is the abbreviation of grams force. Bars indicate the mean values ± standard deviation. Double asterisks (**) represent significant difference of BTS between IR26 and Jiucaiqing at p < 0.01 level.

 


Fig. 2.
Fig. 2.

Chromosomal location of introgressed Jiucaiqing rice segments in chromosome segment substitution lines (CSSLs) and near-isogenic lines (NILs) and quantitative trait loci (QTL) analyses of seed shattering. The presence of a QTL is inferred when there is a significant difference of breaking tensile strength (BTS) between the CSSLs (NIL) and the recurrent parent IR26 at 35 d after heading. (a) Comparison of the shattering between the CSSLs and the recurrent parent IR26; (b–c) Chromosomal location of the introgressed Jiucaiqing rice segments in CSSL 2 and CSSL 14; (d) Frequency of the shattering in BC5F3 population for the QTL qSH1JCQ confirmation on chromosome 1; (e) Chromosomal location of the introgressed Jiucaiqing rice segments in NIL; (f) Comparison of the shattering between NIL and the recurrent parent IR26. Blue bars represent the nonshattering Jiucaiqing genotype region. Green and red bars represent shattering IR26 genotype and heterozygous genotype, respectively. The unit of BTS, gf, is the abbreviation of grams force. Bars indicate the mean values ± standard deviation. Double asterisks (**) represent significant difference of BTS between IR26 and CSSLs (NIL) at p < 0.01 level.

 


Fig. 3.
Fig. 3.

Fine mapping of qSH1JCQ for seed shattering. The qSH1JCQ locus was narrowed down to a 98.4 kb region between markers Jm36 and Jm23 on chromosome 1 using 4230 plants of BC5F4 population. Numbers below the horizontal line are the number of recombinants. Blue bars represent the nonshattering Jiucaiqing genotype region; green and red bars represent shattering IR26 genotype and heterozygous genotype, respectively. Right: The breaking tensile strength (BTS) of grain pedicels at 35 d after heading. The unit of BTS, gf, is the abbreviation of grams force. Bars indicate the mean values ± standard deviation. Double asterisks (**) represent significant difference of BTS between IR26 and BC5F4 plants at p < 0.01 level. Among the 14 genes in this region, gene 7 corresponds to qSH1 (Konishi et al., 2006).

 


Fig. 4.
Fig. 4.

Comparison of the nucleotide sequence at the 12 kb head of qSH1 and the promoter and the open reading frames (ORFs) region of qSH1 among Jiucaiqing, IR26, and Nipponbare. Black boxes indicate coding regions, and white boxes show the 5′ and 3′ untranslated regions. Nucleotides with red color indicate the sequence variation in IR26. Red boxes indicate cis-acting elements, and blue boxes show amino acid. Single asterisk (*) indicates complementary sequences.

 


Fig. 5.
Fig. 5.

(a) Shattering levels and (b–f) expression levels of shattering related genes regulated by the Jiucaiqing allele of qSH1JCQ in various development stages. The breaking tensile strength (BTS) of grain pedicels was tested at 0, 7, 14, 21, 28, and 35 d after heading. The unit of BTS, gf, is the abbreviation of grams force. The transcript levels were determined with quantitative real-time polymerase chain reaction using gene specific primers when 5, 10, 15, and 20 cm panicle length. Transcript levels were calculated relative to the qSH1 when 5 cm panicle length. Bars indicate the mean values ± standard deviation. Single and double asterisks (* and **) represent significant differences between IR26 and NIL at p < 0.05 and p < 0.01 level, respectively.

 


Fig. 6.
Fig. 6.

Comparison of the agronomic traits between IR26 and NIL. (a) Heading date; (b) 1000-grain weight; (c) plant height; (d) panicle length; (e) effective tillers; (f) filled grains per panicle. Bars indicate the mean values ± standard deviation.