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A G R I C U LT U R E & A Q U A C U LT U R E
M ARUNPRASAD/ABHISHEK JACOB (inset)
A tapping system to improve productivity in rubber plantations has been developed and tested by researchers at Prince of Songkla University, Thailand. Over the last 20 years the average size of smallholdings in the main rubber growing areas of southern Thailand has fallen to about two hectares. Hence increasing tapping productivity is a high priority, leading to the adoption of very intensive tapping systems which has resulted in overexploitation, high rates of tapping panel dryness and low productivity. The newly developed “Double Cut Alternative” (DCA) tapping strategy aims to optimise high tapping frequencies, using two different cuts that are tapped alternately to increase time for latex regeneration. Trials since 2007 have found that the DCA system, equivalent to the conventional half spiral cut every two days, provided a latex yield 21 to 22 per cent higher. A network of on-farm trials will compare the DCA system with conventional tapping methods currently in use, and the results so far have been promising. Further tests are needed before implementing the double cut method on a large scale across southern Thailand. Presently, the DCA system has only been tested on 600 clone plantations. Extended farm trials will need to include other rubber clones, in order to validate feasibility and sustainability of the Double Cut Alternative system.
For further information contact: Assoc. Prof. Dr Sayan Sdoodee Faculty of Natural Resources Prince of Songkla University, Thailand Email:sayan.s@psu.ac.th.
Plants of the genus Striga, the world’s most destructive species of parasitic weeds, cause billions of dollars in damage to global agriculture every year. Researchers from the RIKEN Plant Science Center have helped to uncover germination mechanisms for Striga, offering the promise of producing parasiteresistant crops. As parasite plants, Striga possess few storage reserves of their own and survive off nutrients produced by their hosts, which include some of the world’s most important crops such as sorghum and wheat (picture below). Dormant Striga seeds can lie in the ground for many years, only germinating when they sense a host nearby. Triggering this mechanism is the plant hormone strigolactone, though the mechanism responsible is poorly understood. To clarify the processes behind Striga germination the researchers investigated strigolactone production in the model plant Arabidopsis thaliana. As a model plant Arabidopsis is more amenable to experimentation, with some genetic mutants possessing characteristics very similar to Striga. The team analysed the effect of 10,000 molecules on seedling development in Arabidopsis, leading to the first of two important findings: a group of five structurally-similar compounds called ‘cotylimides’ boost production of strigolactone. The presence of cotylimides led to bleaching of seedling leaves. Testing these compounds on 520,000 genetic variants of Arabidopsis, the researchers identified 246 lines which exhibited reduced bleaching, indicating cotylimide resistance. Of these 246 lines, analysis was carried out on those which possessed characteristics similar to Striga, leading to the second important finding. Light was shown to boost strigolactone production showing the plant hormone plays a role similar to sunlight in stimulating germination and greening. By exposing a previously-unknown relationship between light and strigolactone, these results expand our understanding of the germination mechanisms of parasitic plants. When every year across Africa, Asia and Australia weeds of the genus Striga cause billions of dollars in agricultural damage, such findings may contribute to tackling worldwide food security challenges by providing a step toward developing parasite-resistant plant species. For further information contact: Dr Yuji Kamiya Growth Regulation Research Group RIKEN Plant Science Center, Japan Email: ykamiya@riken.jp
MATTBUCK
A cut above for more latex production
Getting to the root of parasitic weed