Girdling and paclobutrazol have been related with the effects on the photosynthetic capacity and carbohydrate content of plants. The physiological changes caused by these methods distress the growth and development of plants in general. A field experiment was carried out from August 2021 to June 2022 on 5 years of open-field Mangifera indica cv. Harumanis trees grown at Malaysian Agriculture Research and Development Institute (MARDI), Serdang, Selangor. The objective of this experiment was to understand the relationship between girdling, paclobutrazol application, combined methods and untreated trees on plant photosynthetic performances and carbohydrate content in the leaves. The treatments were performed on 1st December 2021, and the measurements of leaf gas exchanges and carbohydrate content were performed 4th weeks later on fully expanded leaves shoot, experiencing similar light exposure. In the study, the combination of girdling and paclobutrazol application resulted in a significant decrease in photosynthetic rate (Pn), stomatal conductance (gs) and transpiration rate (Tr) but significantly increase in intercellular CO2 concentration (Ci) and carbohydrate content.

Aims: This experiment aimed to study the effect of girdling, paclobutrazol application, combined methods, and untreated trees on physiological response, vegetative and reproductive growth, and fruiting. Place and Duration of Study: This study was carried out from August 2021 to June 2022 at MARDI, Serdang, Selangor, using five years of open-field Mangifera indica cv. Harumanis trees. Study Design:  The study was arranged in the frame of  randomized complete block design with three replications and three samples per treatment; ANOVA and DMRT at p=0.05 were used for significance and post hoc comparison, respectively. Methodology: Each replication consists of: T1- No induction (Control); T2- girdling at primary branches; T3- soil drenching at 4 ml/l PBZ and T4- girdling at primary branches + soil drenching at 4 ml/l PBZ. The girdling process was performed by removing a 10 mm width ring of bark at all primary branches. Paclobutrazol (25% active ingredient) of the commercial product was used. The treatments were performed concurrently on 1st December 2021 at the same morphological size as the tree subjected to similar light exposure. Results: The combination method of girdling and paclobutrazol application had the most significant adverse effect on internode length. Nevertheless, no significant difference was observed in plant stem diameter, height, number of primary and secondary branches, and number of shoots generated from all treatments. The combined method reflected a significant reduction in stomatal conductance, rate of photosynthesis, and transpiration rate. However, the intercellular CO2 concentration of this combined method and untreated tree is significantly higher. Flowering appears on the leaf buds 90 days after the treatment for paclobutrazol application and the combined method. These methods also resulted in yield per fruit and yield per tree. Conclusion: Based on the results, the combination method of girdling and paclobutrazol application was effective to reduce vegetative growth, suppress physiological capacity, yet the most effective to produce flowering and fruit yield.

Aims: Soils and plant densities are two of the major factors affecting sweet corn growth and yield. Although many worldwide studies were done to evaluate the effect of these factors on sweet corn, it is still necessary to do more study in this area because environmental factors will give significant effect to growth and yield of sweet corn. The objective of this study is to assess yield optimization through different plant densities for different type of soils for sweet corn (Zea mays L.) cultivation. Study Design:  The experiment was carried out from February to May 2018 using split-split plot design with four replications. Analysis of Variance (ANOVA) with probability value of @ 0.05 using LSD was used to analyze the obtained data. Regression analyses were performed using Nonlinear Regression Model (NLIN Procedure); Logistic Growth Model y=A/(1+be-cx) and their rate of change was calculated using its derivate, dy/dx = (Abce-cx)/(1+be-cx)2. Methodology: A variety of sweet corn seed Akik SC422 at (i) four soils which were riverine soil (Tanah Merah, Kelantan), BRIS (Bachok, Kelantan), peat (Simpang Renggam, Johor) and sedentary soil (UPM, Serdang, Selangor) assigned as the main plots with (ii) 1 and 2 row(s) per bed plant arrangements as subplots at (iii) 25 cm and 50 cm planting distances formed as sub-subplots. Results: Interaction between peat at 2-row per bed plant arrangement at 25 cm planting distance produced the highest potential plant height while peat at 1-row per bed plant arrangement at 50 cm planting distance the best in highest potential in stem diameter. The interaction between peat with 1-row per bed plant arrangement at 50 cm planting distance; low plant density produced the highest in cob weight, cob length, cob diameter, thousand kernel’s weight and total sugar content. This was reflected by higher growth rates of photosynthesis rate, leaf area per plant and relative chlorophyll content of each individually plant. However, the interaction between peat with 2-row per bed plant arrangement at 25 cm planting distance; high plant density produced the highest in quantity per hectare. Conclusion: Results of this study confirms that significant differences in the plant growth, physiological attributes and yield components of sweet corn grown on different soil types, plant arrangements and planting distances.