Characterization and fine mapping of () mutant in sorghum [ (L.) Moench].

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The sorghum inflorescence is consisted of sessile (SS) and pedicellate spikelets (PS). Commonly, only SS could produce seeds and each spikelet produces one single seed. Here, we identified a sorghum mutant, named (), which can produce twin seeds in each pair of glumes. We characterized the developmental process of inflorescence in and Jinliang 5 (Jin5, a single-seeded variety) using scanning electron microscope (SEM). The results showed that at the stamen and pistil differentiation stage, could develop two sets of stamens and carpels in one sessile floret, which resulted in twin-seeded phenotype in . Two F mapping populations derived from the cross between Jin5 and , and BTx622B and , were constructed, respectively. The genetic analysis showed that trait was controlled by a single dominant gene. Through bulk segregation analysis with whole-genome sequencing (BSA-seq) and linkage analysis, locus was delimited into a region of around 210-kb on chromosome 6, between the markers and , which contained 32 putative genes. Further analysis indicated that or may be responsible for the twin-seeded phenotype. This result will be useful for map-based cloning of the gene and for marker-assisted breeding for increased grain number per panicle in sorghum.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11032-024-01511-7.