Mathematical Model of Vegetative Growth of Porang (Amorphophallus muelleri) with Different Seed Quality

Abstract

Porang (Amorphophallus muelleri) is a tuber plant used in the industrial production of glucomannan. Porang can be cultivated with bulbil (katak tubers) and spontaneously harvested vegetatively. Under certain harvest and storage conditions, infected bulbils can reduce seed quality, viability, and growth. This study developed a mathematical model to predict the vegetative growth of porang with different bulbil seed qualities. The physical properties and plant growth parameters of 90 seeds of non-infected and infected bulbil were measured and divided into the calibration set comprised of 60 samples. The validation set included the remaining 30 samples. Polynomial models were used to predict plant height which was developed based on the calibration set. In contrast, model evaluation was used Root Mean Square Error (RMSE), Mean Absolute Error (MAE), and Means Absolute Percentage Error (MAPE) were used to compare the calibration and validation set with the prediction data of plant height. The mathematical growth model using the polynomial model yielded the coefficient of determination (R 2 ) of 0.9811 and 0.9824, with RMSE 0.4680 and 2.1504, MAE 0.0111 and 0.6694, and MAPE 0.8661 and 5.3096, for the calibration and validation sets of noninfected seed, respectively. Infected bulbil produced R 2 of 0.9931 and 0.9926, with RMSE 0.5641 and 4.7765, MAE 0.0549 and 1.5163, and MAPE 3.4109 and 4.5561, for the calibration and validation sets, respectively. The R 2 and the validation model showed that the mathematical model was feasible to predict the growth of non-infected and infected porang bulbil to assess the vegetative growth of porang seeds of different qualities.

Effect of Varying Color LED Lights on Porang (Amorphophallus muelleri) Bulbil Seed Germination and Porang Plant Vegetative Growth Phase

“…The 71% combination LED treatment is closest to the control treatment's 79% humidity. According to other reports, this study's microclimate temperature and humidity are appropriate for the optimal condition; porang plants thrive at 25-35 o C and 50-80% RH [22].…”

“…The analysis structures of multiple linear and polynomial regression models are identical. Each rank or order in a polynomial model modifies the initial variable, transforming a free variable into a non-free variable [22].…”

“…The model was evaluated using root mean square error (RMSE), mean absolute error (MAE), mean absolute percentage error (MAPE), and coefficient of determination (R 2 ). The polynomial equation and model evaluation are listed in equations ( 6) - (10); n is the number of samples, ý is the predicted value of the plant height at the i-point, and y represents the actual plant height at the i-point [22].…”