RESEARCH ARTICLE

Journal of Oil Palm Research Vol. 33 (1) March 2021, p. 46-55

ESTIMATING THE YIELD LOSS OF OIL PALM DUE TO Ganoderma BASAL STEM ROT DISEASE BY USING BAYESIAN MODEL AVERAGING

ASSIS KAMU*; CHONG KHIM PHIN**; IDRIS ABU SEMAN‡; DARMESAH GABDA* and HO CHONG MUN*

DOI: https://doi.org/10.21894/jopr.2020.0061
Received: 21 December 2019   Accepted: 9 July 2020   Published Online: 11 September 2020
ABSTRACT

It is very crucial to planters to estimate the yield loss due to Ganoderma Basal Stem Rot (BSR) disease in oil palm. However, currently there is a limited mathematical model available that can be used for that purpose. Therefore, this empirical study was conducted to build a mathematical model which can be used for yield loss estimation due to the disease. Three commercial oil palm plots with different production phase (i.e. steep ascent phase, plateau phase, and declining phase) were selected as the study sites. The yield and disease severity of the selected palms in the three study sites were recorded for the duration of twelve months. Model averaging approach using Bayes theorem was used to build the model. This is also known as Bayesian Model Averaging (BMA). The BMA model revealed that planting preparation technique was the most important predictor of oil palm yield loss, followed by disease progress (measured using area under the disease-progress curve, AUDPC), disease severity, number of infected neighbouring palms, and two interaction terms. By using the developed BMA model, it was estimated that the economic loss can be up to 68% compared to the attainable yields of all the infected palms.

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* Faculty of Science and Natural Resources,
Universiti Malaysia Sabah,
UMS Road Kota Kinabalu,
88400 Kota Kinabalu,
Sabah, Malaysia.
E-mail: assis@ums.edu.my

** Sustainable Palm Oil Research Unit (SPOR),
Faculty of Science and Natural Resources,
Universiti Malaysia Sabah,
Jalan UMS,
88400 Kota Kinabalu,
Sabah, Malaysia.

‡ Malaysian Palm Oil Board,
6 Persiaran Institusi,
Bandar Baru Bangi,
43000 Kajang,
Selangor, Malaysia.