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Exogenous application of different plant growth regulators has raised some concern for improving quality and quantity of yield in different crops especially under unfavourable conditions. Rice (Oryza sativa L.) is an important crop in the world and salinity is one the main abiotic stress factor affecting its productivity. To determine genotypic and ontogenetic variations of different physiological activities including water and nutrient uptake during salinity and effectiveness of exogenous GA3 application on those parameters, two different rice varieties (Pokkali and MR219) were cultivated under controlled environment using five different salinity levels (0, 50, 100, 150 and 200 mM NaCl) and with or without application of GA3 (150 ppm foliar spray). A remarkable reduction in grain yield (even no grain formation at higher salt concentration) in both rice varieties was observed during our observation. Rice variety MR219 was less competitive than Pokkali under salinity while exogenous application of GA3 is useful to mitigate salinity stress in rice as it increased different yield components and yield (8.7% in MR219 and 16.7% in Pokkali). Considering the trends of growth reduction due to salinity and progressive impact of exogenous GA3 application on different morphological, physiological and biochemical activities, it can be stated that application of GA3 is useful to mitigate salinity stress and its effectiveness is more active to salt tolerant varieties.

Ganoderma boninense, causes basal stem rot disease in oil palm, which leads to severe losses to the palm oil industry. The antagonistic effect of Trichoderma harzianum on G. boninense (a causal pathogen for oil palm) was tested by in vitro and in vivo studies. T. harzianum inhibited the mycelia growth of G. boninense on in vitro plate assay experiment and in vivo on the glass house grown oil palm plants. During the in vivo experiment, at first time point after one month, G. boninense development was found in oil palm root tissues in control plants whereas in T. harzianum treated plants no disease symptoms were observed until at the end of the experiment. It is a broad spectrum approach to use T. harzianum to control G. boninense infection of oil palm.