American scientists have genetically modified tobacco plants so that they are 40% larger than normal. The researchers say they have found a way to overcome natural limitations during the process of photosynthesis that limit crop yields. They believe that the method can be used to significantly increase yields of important crops like rice and wheat.
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Scientists are increasingly concerned about the planet’s ability to feed the growing population in times of severe climate change.
Worldwide demand for agricultural products is expected to increase by 60-120% by mid-century, compared to 2005. Yields, however, are growing by less than 2% per year, so a significant food deficit is likely to emerge by 2050.
Although the use of fertilizers, pesticides, and mechanization has increased in recent decades, their potential for future crop growth is limited. Instead, scientists are increasingly trying to improve the process of photosynthesis. Plants use sunlight energy to convert carbon dioxide and water into sugar, but the process of producing some toxic compounds reduces the potential yield. The toxins are processed by the plant in a process called photorespiration, which exhausts precious energy that the plant could have used to increase yield.
Scientists decided to find a way to make photosynthesis less energy-consuming. «We have tried three different biochemical constructions to shorten this very energy-consuming process,» says lead author Paul South of the US Agricultural Research Service.
«It is estimated that it can cause a significant yield loss of up to 36% on crops such as soybeans, rice, fruits and vegetables, and we have tried to make this shortcut more energy efficient — and field-tested this increases plant biomass by 40%.»
An important aspect of the food deficit problem is that it becomes more common at high temperatures and in drought conditions. The researchers chose tobacco because it is easy and quick to modify at the gene level. The team hopes to use the results of the study to increase yields of soybeans, rice, potatoes, and tomatoes.