This study evaluated the photosynthetic gas exchange of mature oil palm and understory vegetation in a drained tropical peatland plantation located in Riau, Indonesia. Measurements were taken six times a day on the 17th frond of 16-year-old palms and two dominant understory species (Asystasia gangetica and Nephrolepis biserrata) over six periods from February 2020 to March 2022. The photosynthetic rate of oil palm ranged from 18.44 to 43.47 µmol CO2/m2/s, and its stomatal conductance ranged from 0.050 to 0.067 mol H2O/m2/s. The transpiration rate ranged from 577.83 to 1,189.31 µmol H2O/m2/s. Stomatal conductance was strongly linked to transpiration (r = 0.775, p < 0.001). Understory species also showed high photosynthetic rates, with N. biserrata at 25.31–31.49 µmol CO2/m2/s and A. gangetica at 23.53–36.37 µmol CO2/m2/s. Diurnal patterns showed that physiological activity generally increased from morning to noon. These results demonstrate variation in leaf physiology and photosynthetic carbon assimilation in both canopy and understory plants on drained peatlands.
Cassava is an important staple food and an alternative to rice that exhibits relative resilience to both abiotic and biotic stresses. The development of cassava genotypes through mutation breeding has been conducted by a research team from the Department of Agronomy and Horticulture, IPB University. Currently, approximately 10 putative mutant cassava genotypes of M1V14 have been obtained, including G6-2-15-1-1, G6-2-15-5-3, and G6-2-15-3-3, which have high leaf mineral content and substantial tuber yield. This research aimed to evaluate morphological responses and identify growth patterns of cassava mutant genotypes under low-pH conditions with aluminum. By comparing control plants with Al-treated plants. ‘Vamas-1’, ‘Gajah’ (wild type), and putative mutant G6-2-15-1-1, and G6-2-15-5-3 exhibited greater reduction in plant and root growth compared to the putative mutant G6-2-15-3-3. All genotypes showed varying degrees of growth inhibition at the highest Al treatment (6 mM), indicating differences in Al tolerance. Based on the PCA analysis, most root morphological traits and plant biomass were strongly associated with the putative mutant G6-2-15-3-3. In addition, traits such as root diameter, number, length, and biomass were characteristic of ‘Gajah’, whereas the number of shoots, time of shoot emergence, and leaf biomass were characteristic of ‘Vamas-1’. In addition, based on leaf biomass and basal root morphology, the putative mutant G6-2-15-3-3 shows potential as a new superior genotype with high leaf and tuber production, offering additional economic value. The development of this variety could serve as an alternative for farmers in developing countries, especially in Indonesia, to address the challenges posed by acidic soils with high aluminum content.
Cocoa is known to require shade during its growth phase. This research is a structured comparative field study to evaluate the effect of different shade tree species on cocoa root morphology, leaf nutritional status, and certain bean characteristics (100-bean dry weight and protein content). The study was conducted on cocoa plants under three species of shade plants and one control without shade, such as Albizia chinensis (sengon), Cocos nucifera (coconut), Cassia spectabilis (ramayana), and without shade. In the research field conditions, the planting ratio is that every 1 shade tree shades 1 cocoa plant sample being evaluated. The parameters observed included total root length at various soil depths, cocoa leaf nutrient content (N, P, K, Ca, Mg, B), dry weight of 100 beans, and protein content of cocoa beans. The results showed that shade tree species significantly influenced the total length of cocoa roots at certain soil depths (0–10 cm and 20–30 cm), and significantly influenced the dry weight of 100 beans and protein content. The C. spectabilis shade tree produced the highest dry weight of 100 beans and the highest protein content under the conditions of this study compared to A. chinensis and C. nucifera. Cocoa grown under C. spectabilis exhibited favorable bean and leaf nutrient characteristics under the conditions of this study. However, a full evaluation of causality requires further research using a multi-site design.
The seed harvesting process for Amorphophallus muelleri Blume is complicated by asynchronous flowering and fruiting. These factors affect the quality of the fruit and seeds, including fruit color, seed viability, and vigor. Pericarp color, as a simple indicator of fruit maturity, can be used to determine the best harvest time. At the M30% fruit maturation stage (30%–49% red pericarp), pericarp colors were more diverse across positions, including dark red, orange, yellow, and greenish yellow. The M50% (50%–74% red pericarp) included red, orange, yellow, and greenish yellow. The pericarp colors at M75% (>75% red pericarp) were more uniform, consisting of red, orange, and yellow. There were no significant differences in seed moisture content among spadix maturity stages, 62.49% (M30%), 63.42% (M50%), and 61.07% (M75%). Maturity stage and position affected the physical and physiological quality of the fruit and seeds. The well-filled and rotten fruits in the spadix increased as fruit maturity advanced. The highest number of empty fruits was found at M30%, while the highest seed dry weight was found at M50%. The proximal position had a higher percentage of empty fruits and a greater dry weight than the distal and middle positions. M75% had the highest average rate of well filled fruit (90.83%) and the lowest average dry weight (8.1 mg per seed). The M50% maturity stage had the highest average dry weight (9.3 mg per seed) and the highest average viability of 93.1%, indicating that the seeds had reached physiological maturity.
Fertilizer recommendations for newly released rice varieties need to be optimized because nutrient requirements may vary among varieties and growing environments. ‘IPB 13S’ is a newly released rice variety developed by IPB University, and information regarding its optimal nitrogen (N), phosphorus (P2O5), and potassium (K2O) requirements is still limited. Therefore, this study aimed to determine the optimal rates of N, P2O5, and K2O fertilizers for ‘IPB 13S’ rice. The study was conducted from May to September 2024 at the Sawah Baru Experimental Farm, Dramaga, Bogor, Indonesia. Three fertilizer experiments (N, P2O5, and K2O) were arranged in a randomized complete block design (RCBD) with five fertilizer levels (0%, 50%, 100%, 150%, and 200% of the regional recommended rate) and three replications. Growth parameters, yield components, grain yield, and nutrient use efficiency were evaluated. Data were analyzed using analysis of variance, orthogonal polynomial analysis, and quadratic regression. The results showed that N, P2O5, and K2O applications significantly affected plant growth, yield components, grain yield, and nutrient use efficiency. Quadratic regression analysis identified optimal fertilizer rates of 170 kg N/ha, 53 kg P2O5/ha, and 71 kg K2O/ha, resulting in the highest predicted grain yield. These findings indicate that variety-specific fertilizer recommendations are needed to optimize grain yield and nutrient use efficiency in the ‘IPB 13S’ rice variety.
