Evaluation of Grain Yield of Multi-Seeded Sorghum Mutants Under Field Conditions.

Sorghum (Sorghum bicolor L. Moench) has highly branched panicles with primary, secondary, and tertiary branches. The flower branch ends with a terminal triplet spikelets, one sessile spikelet that is directly attached to the branch and two pedicellate spikelets that are attached to the branch through a short pedicel, followed by one or more spikelet pairs (one sessile and one pedicellate). In BTx623 and most other known lines, only the sessile spikelets can develop into seeds and the pedicellate spikelets, occasionally develop anthers, will eventually abort. We isolated a series of multi-seeded (msd) mutants, in which all spikelets are fertile. In addition, the mutants displayed increased length and total number of primary and secondary inflorescence branches. The msd mutants has the potential to triple grain number and double grain weight per panicle on single plant basis. To remove background mutations, the msd mutants have been backcrossed to BTx623 for two to five generations. The backcrossed seeds are used to evaluate the yield potential under field conditions to determine if this trait can be used to improve grain yield on acreage basis.