AGRIVITA, Journal of Agricultural Science
Vol 48, No 3 (2026): October 2026 (IN PRESS)

Thermal Unit Approach for Determining Flower and Fruit Development Phases in 70 Accessions of the Angola Collection of the International Oil Palm Research Institute, at Adolina Seed Garden, PTPN IV

Sujadi, S. (Unknown)
Sofia, Diana (Unknown)
Rosmayati, R. (Unknown)
Siregar, Luthfi Azis M. Azis M. (Unknown)
Rahutomo, Suroso (Unknown)



Article Info

Publish Date
01 Sep 2026

Abstract

Phenology is the study of periodic plant development influenced by environmental conditions. The thermal unit approach is a common concept to measure the effect of temperature on phenology. This study aimed to identify bunch phenology in 70 Angola accessions of the IOPRI collection using the thermal unit concept. The research was conducted at the Angola Germplasm Collection Garden, Adolina Seed Garden, North Sumatra from January 2017 to December 2022. Observations of bunch development were made on 70 trees every 10 days. Climate observations were made using the Automatic Weather Station Davis Vantage Pro II, including rainfall, air temperature, humidity, and wind speed.The study results revealed that among 70 Angola accessions, the thermal unit (oC days) required from the first leaf appearance to physiologically ripe bunches ranged from 4.980 to 6.450 oC days, with a time span of 409 to 530 days. Among these accessions, Accession AGO054/33-2 stood out as the one with the shortest development period, requiring only 409 days from the first leaf to physiologically ripe fruit. Accession AGO54/33-2 also showed lower heat accumulation compared to other Angola accessions, while Accession AGO105/18-27 required the highest heat accumulation. Statistical analysis indicated significant differences in thermal unit values among the accessions.

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Journal Info

Abbrev

AGRIVITA

Publisher

Subject

Agriculture, Biological Sciences & Forestry

Description

AGRIVITA Journal of Agricultural Science is a peer-reviewed, scientific journal published by Faculty of Agriculture Universitas Brawijaya Indonesia in collaboration with Indonesian Agronomy Association (PERAGI). The aims of the journal are to publish and disseminate high quality, original research ...