Stem Carbohydrate and Lignin Concentrations in Sorghum Hybrids at Seven Growth Stages

McBee, George G.; Miller, Fred R.

Stem Carbohydrate and Lignin Concentrations in Sorghum Hybrids at Seven Growth Stages

1993

McBee, George G. | Miller, Fred R.

Grain yield and quality of vegetative material from sorghum [Sorghum bicolor (L.) Moench] are affected by carbohydrate and lignin partitioning within the plant and translocation of nonstructural carbohydrates (NSC) to the kernels. This field study was conducted during two growing seasons to determine concentrations of NSC, hemicellulose (HC), cellulose~ and lignin in four sorghum hybrids at seven growth stages from panicle differentiation through 45 days post anthesis (DPA) of plants. Stem NSC increased to 148 g kg⁻¹ in ATx378 × RTxT000, 208 in ATx378 × RTx430, and 268 in ATx623 × SC599- 11E from PD to ≈15 DPA, decreased to 47, 85, and 183 between 23 and 32 DPA (kernel blacklayer) and then increased to 280, 340, and 380 at 45 DPA. Stem NSC increased at most stages in ATx623 × Hegari from panicle differentiation to a maximum of 450 g kg⁻¹ at 32 DPA. Hemicellulose decreased and cellulose increased from panicle differentiation to preboot, but concentrations remained relatively stable from anthesis to 45 DPA, with ranges of 425 to 475 g HC kg⁻¹ neutral detergent fiber (NDF) and 440 to 490 g cellulose kg⁻¹NDF. Lignin increased from panicle differentiation to 15 DPA and then stabilized, with concentrations ranging from 75 to 105 g kg⁻¹ NDF. The concentration patterns indicate plant breeders can increase stem NSC in hybrids during kernel filling with careful selection of R.lines and that quality of vegetative material intended for forage or CH₄ production can be influenced by harvest at selected growth stages. Contribution of the Texas Agric. Exp. Stn.

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