Genotype-environment Interaction Of Main Agronomic Traits And Energy-related Components In Sweet Sorghum

Breeding new varieties with high yield and quality in sweet sorghum is very important for reducing the cost of ethanol production. Knowledge of the genetic variation, and genotype-environment interaction will help sweet sorghum breeders improve relevant traits through selective breeding and genetic engineering. This study was conducted to understand the genotypic variation and environmental effects of main agronomic traits and energy related components of sweet sorghum.81 sweet sorghum[Sorghum bicolor(L.)Moench] cultivars were grown over two years at three locations. Genetic variance and genotype-environment interaction of main agronomic characteristics and energy related components in sweet sorghum were compared and clustered. The main results are obtained as follows.1. A new method of estimating sugar content of stem in sweet sorghum was established, which could be used to determine the energy related components in a large scale. Samples were randomly selected, and heads, leaves and sheathes were removed. The juice and bagasse were collected after crushing. The juice sample was centrifuged at low temperature, then measured by HPLC.The sugar content in stem (Ss) was estimated with sugar content of juice (Sj) as a formula:Ss=J×Sj+B×Sj×Wb/Wj, where J is juice extraction (%), B is bagsse extraction (%), Wj is moisture of juice extracted (%), Wb is moisture content of bagsse (%). Bagsse sample was dried to constant weight in 80℃, the moisture content was calculated, hemicellulose, cellulose and lignin content were analysed as Van Soest. Sum of hemicellulose, cellulose and lignin content (F%) in stem was estimated as a formula: F(%)=B×Fb×(1-Wb), where B is bagsse extraction (%), Fb fibre component content in dried bagsse(%), Wb is moisture content of bagsse (%).2. Genetic variation and genotype-environment interaction in main agronomic traits were determined. Genetic variation of period of duration, plant height, stem diameter, internodes number, fresh weight per plant, stem fresh weight per plant, grain weight per spike, Brix and moisture content were significant at 1% level. The variability of period of duration is 82 d-144 d, the coefficient of variation is 9.47%; The variability of plant height is 167.1 cm-386.2 cm, the coefficient of variation is 13.95%; The variability of stem diameter is 14.13 cm-25.82 cm, the coefficient of variation is 11.45%; The variability of internodes number is 7.2-20.8, the coefficient of variation is 24.03%; The variability of fresh weight per plant is 0.501 kg-1.715 kg, the coefficient of variation is 22.75%; The variability of grain weight per spike is 0.024 kg-0.081 kg, the coefficient of variation is 23.48%; The variability of Brix content is 12.5%-22.10%, the coefficient of variation is 11.54%; The variability of moisture is 38.48%-87.37%, the coefficient of variation is 14.03%; The variability of stem fresh weight per plant is 0.236 kg-1.384 kg, the coefficient of variation is 33.62%.Genotype-environment interaction of plant height, stem diameter, internodes number, fresh weight per plant, stem fresh weight per plant, Brix and moisture were significant at 1% level.3. Genetic variation and genotype-environment interaction in energy related components were determined. Genetic variation of glucose, fructose, sucrose, total sugar, hemicellulose, cellulose, lignin content were significant at 1% level. The variability of glucose content is 0.59%-3.43% in fresh stem, the coefficient of variation is 42.13%; The variability of fructose content is 0.33%-2.77%, the coefficient of variation is 36.43%; The variability of sucrose content is 1.11%-11.28%, the coefficient of variation is 41.65%; The variability of total sugar content is4.48%-13.01%, the coefficient of variation is 21.77%; The variability of hemicellulose content is 3.69%-9.54%, the coefficient of variation is 19.47%; The variability of cellulose content is 3.46%-9.48%, the coefficient of variation is 17.08%; The variability of lignin content is 0.35%-1.75%, the coefficient of variation is 28.04%; The variability of sugar yield is 0.015 kg-0.186 kg, the coefficient of variation is 31.34%; The variability of fibre yield is 0.027 kg-0.148 kg, the coefficient of variation is 33.44%.The effects of different locations were significant at 1% for glucose, total sugar, hemicellulose content. The content of fructose, sucrose, cellulose and lignin had no significance variation between Beijing and Hebei. The interaction of genotype and location was significant.4.10 genotypes were recommended for breeding use according to their main agronomic traits and energy related components. It contains BJK236, Keller, Tianxuan116, Tianxuan174, Tianxuan20, Jitian3, XTL-1, Sart, Bailley, Wary.