Plants grow bigger and more vigorously through changes in their inter...(combining the same species). The res...)

The research team discovered a direct connection between circadian clock regulators and growth vigor in both hybrids and polyploids. Circadian clocks control growth, metabolism and fitness in plants and animals.

They found that some of these regulators, known as transcriptional repressors, were more repressed during the day in the hybrids and polyploids, leading to increases in their photosynthesis and starch accumulation.

"This connection was a bit of surprise, but it makes a lot of sense," says Chen.

With this knowledge, Chen says they can now develop genomic and biotechnological tools to find and make better hybrids and polyploids.

"We can think about screening parent plants for these genes and selecting the ones to make the best hybrids," says Chen. "This could all be done through traditional breeding techniques and could have a huge impact on generating higher biomass crops for biofuels and increasing yield in many food crops."

The hybrid vigor or "heterosis" phenomenon was first observed by Charles Darwin in 1876, and was extensively studied in corn in the early 1900s. All corn in the U.S. is hybrid.

Many of the important polyploid crops, such as wheat and cotton, are known as allopolyploids, because they are formed from two or more different species. Chen and his colleagues study standard hybrid and allopolyploid Arabidopsis, cotton and corn.

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