Fig. 1. Design of a novel hybrid rice seed production system enabling mechanical mixed harvesting and purity assurance. P/TGMS, Photoperiod/thermo-sensitive genic male sterility; Be, Bentazon herbicide; Im, Imidazolinone herbicide. RBSI, Resistant to bentazon and sensitive to imidazolinone; SBRI, Sensitive to bentazon and resistant to imidazolinone; RBRI, Resistant to both bentazon and imidazolinone. C (dominant) and c (recessive) alleles for resistance to bentazon. A (dominant) and a (recessive) alleles for resistance to imidazolinone. The red ‘×’ represents hybridization and ‘⊗’ represents self‐pollination. ‘♀’ and ‘♂’ represent female and male parents, respectively.

Fig. 2. Breeding process of indica rice line AP9311, phenotype of AP9311, and editing CYP81A6 gene by CRISP/Cas9-mediated method to generate sensetive bentazon lines. A, Breeding process of indica rice line AP9311. B and C, Phenotype of AP9311 plants in paddy field and potted soil. Scale bar, 20 cm. D and E, Seeds and grains of AP9311. F, Gene structure of CYP81A6 (Os03g0760200) and three sgRNA sites used in gene editing. Target-site DNA sequences of each sgRNA in WT (AP9311) and the mutations in three mutants (cyp-1, cyp-2, and cyp-3). The blue nucleotides represent target sequences and the red nucleotides represent PAM (protospacer adjacent motif). Inserted nucleotides are shown in green lowercase letter(s), and deleted nucleotides are marked with ‘‒’. Numbers with ‘-’ and ‘+’ represent the number of deleted and inserted nucleotides, respectively. WT, Wild type; UTR, Untranslated region. G, Phenotypes of AP9311 and its mutants cyp-1, cyp-2, and cyp-3 after application of bentazon (50 mg/mL). H, Herbicide spraying experiment. CK means not treated by herbicides. Im and Be represent treatment with imazamox and bentazon, respectively. Scale bars, 2 cm.