respectively, in accordance with a Mendelian segregation ratio of
3:1 (2 =3.68 < 20.05=3.84). This result suggests that the brittle
culms phenotype is controlled by a single recessive gene, which we
took a map-based cloning approach to isolate. Primary mapping
using 100 F2 mutant individuals located this gene between two
Indel markers ha1 and ha4 on the long arm of chromosome 9
(Fig. 6A and Table 1). Fine mapping using 5 new Indel markers and