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The amendment of soils with silicate (Si) compounds is essential to promote growth performance and control Fusarium wilt disease in bananas. Two successive greenhouse trials were conducted at the experimental farm of the University of Putra Malaysia. The treatments were arranged in split plots using a randomized complete block design (RCBD) with four replicates to investigate the effects of Si compounds and application frequency on controlling FOC. Si compounds were used at a constant concentration of 0.1%: T0 (control), T1 (13% SiO2:20% K2O), T2 (26.6% SiO2:13.4% K2O) and T3 (36.2% SiO2:17% Na2O). There were three application frequencies by day intervals (DI): 0DI (without any application), 7DI (12× within 12 weeks after transplanting (WAT)), 15DI (6× within 12 WAT) and 30DI (3× within 12 WAT). From these findings, we observed that the photosynthesis rate started to increase from 10.6 to 19.4 µmol CO2 m−2s−1, when the total chlorophyll content started to increase from 3.85 to 7.61 mgcm−2. The transpiration rate started to increase from a value of 1.94 to 4.31 mmol H2O m−2s−1, when the stomata conductance started to increase from 0.237 to 0.958 mmol m−2s−1. The proline content started to increase from 22.89 to 55.07 µmg−1, when the relative water content started to increase from 42.92 to 83.57%.

Biostimulants such as silicate (SiO32−) compounds and antagonistic bacteria can alter soil microbial communities and enhance plant resistance to the pathogens and Fusarium oxysporum f. sp. cubense (FOC), the causal agent of Fusarium wilt disease in bananas. A study was conducted to investigate the biostimulating effects of SiO32− compounds and antagonistic bacteria on plant growth and resistance of the banana to Fusarium wilt disease. Two separate experiments with a similar experimental setup were conducted at the University of Putra Malaysia (UPM), Selangor. Both experiments were arranged in a split-plot randomized complete block design (RCBD) with four replicates. SiO32− compounds were prepared at a constant concentration of 1%. Potassium silicate (K2SiO3) was applied on soil uninoculated with FOC, and sodium silicate (Na2SiO3) was applied to FOC-contaminated soil before integrating with antagonistic bacteria; without Bacillus spp. ((0B)—control), Bacillus subtilis (BS), and Bacillus thuringiensis (BT). Four levels of application volume of SiO32− compounds [0, 20, 40, 60 mL) were used. Results showed that the integration of SiO32− compounds with BS (108 CFU mL−1) enhanced the physiological growth performance of bananas. Soil application of 28.86 mL of K2SiO3 with BS enhanced the height of the pseudo-stem by 27.91 cm. Application of Na2SiO3 and BS significantly reduced the Fusarium wilt incidence in bananas by 56.25%. However, it was recommended that infected roots of bananas should be treated with 17.36 mL of Na2SiO3 with BS to stimulate better growth performance.

Biological control of pathogens continues to be developed with antagonistic rhizobacteria is a promising strategy for banana plant protection. This study aimed to assess the ability of Bacillus subtilis on suppression of Fusarium wilt, biochemical changes and leaf gas exchange under water stress condition on banana cultivar Berangan. Different water stress was given based on field capacity at [well watered (100% FC), mild stress (75% FC) and severe stress (50% FC) and inoculated with different volume of Bacillus subtilis (0, 20, 40, and 60 mL) at concentrations of 108 CFU mL-1. The plantlets were challenged inoculated with Fusarium oxysporum one week after Bacillus subtilis were applied. The treatments were assigned by split plot design in randomized complete block design arrangement. The plants were destructively sampled at 45 and 90 day after transplanting (DAT). Results showed that, applications of Bacillus subtilis at high rate (60 mL) reduced disease incidence by 35.28% and 45.09% at 45 and 90 DAT respectively. Disease severity decreased by 39.83% at 45 DAT and increased by 45.09% at 90 DAT and under well watered conditions. The malondialdehyde (MDA) content was high in control treatment than the plants inoculated with Bacillus subtilis. To summarize, inoculation with 60 mL of Bacillus subtilis in rhizosphere soil to fight against Fusarium wilt could be promoted the plant health under water stress condition. [Fundam Appl Agric 2018; 3(3.000): 515-524]

A field investigation under tropical climate was undertaken in the research plot of the Universiti Putra Malaysia, Selangor, Malaysia to study the effects of exogenous application of plant growth regulators on growth performance, physiology changes and biochemical analysis of banana plants (Musa acuminata cv. Berangan) under irrigated and rainfed condition. The experiment was laid out as split-plot in randomized complete block design. Results showed that, banana plants grown under the rainfed condition significantly reduced morphological characters such as plant height, pseudo-stem, canopy diameter, but enhanced accumulation of proline and malondialdehyde content in leaves tissue of stress-treated plants. Physiological characters which include total chlorophyll content, relative water content and electrolyte leakage were measured and has indicated significant effect under two different water regimes. Application of plant growth regulators on Berangan banana under different water regimes able to tolerate water stress conditions by changes in vapour pressure deficit as affected by decreasing stomata opening besides enhanced net photosynthesis to produce higher yield of banana fruits.