GT Biplot Analysis for Silage Potential, Nutritive Value, Gas and Methane Production of Stay-Green Grain Sorghum Shoots

Abstract

© 2017, Pontificia Universidad Catolica de Chile, Facultad de Agronomia e Ingenieria Forestal. All rights reserved. This study was conducted to investigate the possible silage of stay-green sorghum genotypes using GT biplot analysis. Following the grain harvest, 41 sorghum genotypes were chopped to make silage. Biochemical analyses were performed after 60 d of silage. The results revealed that green herbage yields varied between 13.40–65.96 t ha-1, pH between 3.92–4.25, dry matter ratios between 24.26–35.83%, crude protein ratios between 3.44–7.03%, acid detergent fiber (ADF) ratios between 27.46-52.01%, neutral detergent fiber (NDF) ratios between 40.80–69.12%, crude ash ratios between 5.89– 15.14%, lactic acid contents between 1.657–4.914%, and propionic acid contents between 0.000–0.247%. Methane production values varied between 14.15–21.80%, gas production between 18.51–47.36 mL, metabolic energy (ME) between 6.68–11.67 MJ kg-1DM, and organic matter digestibility (OMD) between 47.20–89.93%. According to GT biplot analysis, there were positive correlations among ADF, NDF and DM; among methane, ME, OMD and gas-methane production; and among acetic, butyric and propionic acids, pH, ash and protein contents. There were negative correlations among gas production, ADF, and NDF and among herbage yield, crude protein, organic acids, pH and crude ash. Among the genotypes, Sugargraze was prominent with herbage yield, while genotypes G4 and G3 were prominent with crude protein. Considering all parameters, genotype G20 seemed to be the ideal genotype. Although some silage samples had low silage and nutritional characteristics, others yielded values close to or even higher than full sorghum silage. These varieties can constitute a quality roughage source for livestock in winter. Further breeding research on stay-green genotypes may provide significant contributions to plant and livestock production activities.