The stepwise regression analysis method for estimating sorghum production in Karangmojo

Sorghum is a multifunctional crop that can be utilized as a source of food, feed, and bioenergy. Sorghum is a plant that can adapt to land with optimal conditions, dry land with
minimal nutrients and tolerant to pests and diseases. Sorghum has been widely cultivated in
Indonesia, one in Gunungkidul, Yogyakarta. Sorghum production is influenced by several
agronomic characteristics. The purpose of the study was to determine agronomic variables that
affect sorghum production. The research was conducted in Karangmojo, Gunungkidul, Special
Region of Yogyakarta, from October 2022 to March 2023. Sorghum varieties were local varieties
as well as national superior varieties which are usually planted by local farmers. A total of 10
variables were analysed for their significance level on sorghum yield. The collected data were
then processed using a multiple linear regression model (stepwise) using SPSS 16.0. The results
showed that of the 10 agronomic variables observed, two variables contributed to the sorghum
production, namely panicle weight and days to harvesting. The regression model from stepwise
results is y = 8.884 + 0.036x3 – 0.062x10, with R2 = 0.754. This result indicates that the two
independent variables are the main variables in determining sorghum production in Karangmojo