Scientists recorded eight to ten percent more yield in the field by a new
genetically modified (GM) corn after overexpressing a gene responsible for
plant growth. The increase in yield is sustained whether the plant is
exposed to optimal or poor growing conditions.
GM corn has been planted globally for the past 23 years, most of which are
insect and herbicide-resistant. Now, scientists at Corteva Agriscience are
developing a new kind of GM corn as they try a new approach to improve its
yield and yield stability. By changing the expression of a single maize
gene, they can create a significant positive change in its grain yield
trait,which is known to have complex genetics.
Specific genes have long been identified to work like switches for a plant's
growth and yield. One gene, zmm28, is among a specific group the genes that
play diverse roles in plant growth and development, including flower
regulation and fruit ripening. zmm28 was specifically identified to turn on
when corn plants begin to flower. The scientists binded this gene with a new
promoter to control its activation, resulting to the gene being turned on
earlier than expected, therefore boosting the gene's beneficial effects to
the plant even after flowering. Their study proved that extending the
expression of zmm28 changes the vegetative and reproductive growth
parameters of maize leading to the plant's elevated plant carbon
assimilation, nitrogen usage, and plant growth. These positive traits are
associated with consistent increase in yield in the field.
To date, commercialized GM hybrid corn are known to increase yield from 3%
to 5% compared to conventional corn. The new GM corn with overexpressed
zmm28 has shown to increase yield from 8% to 10% during the field trials
conducted by the scientists. The development of GM crops that feature
increase yield traits have long been viewed as a means to address the
increasing demands of grain and food supply to sustain the growing global
population while conserving the environment at the same time.