"We're going to change the sex of the papaya to help the farmers," said University of Illinois plant biology professor Ray Ming, leader of a new initiative to assist farmers who are frustrated with the bizarre sexual evolution of the papaya.
Papayas already come in three sexual varieties: male, female and hermaphrodite, but it is only the hermaphrodite varieties that produce the succulent fruit that is sold commercially. The problem for farmers is that seeds from hermaphrodite varieties don't always produce more hermaphrodites, and it is impossible to tell the sex of a seed until it has grown up and flowered.
To cope, farmers currently plant four or five seeds together to improve the odds that a particular plot will sprout at least one hermaphrodite. Once they grow old enough to identify, farmers cut down the undesired plants and leave only the fruit-bearing bush.
As a result, production costs are high and farmers use more water and fertilizer than would be necessary if they only had to grow hermaphrodite papayas. Furthermore, the plants tend to develop poor root systems and a small canopy due to the crowding, which delays fruit production.
But with the help of modern science and genetics, Ming and his colleagues have come up with a crafty solution: modify the sex chromosomes of the papaya so that seeds produced by hermaphrodite plants only spawn other hermaphrodites.
Although there are ecological concerns associated with genetically modified plants, there are also environmental trade-offs which would be beneficial for farmers and the local ecosystem. Less water and fertilizer would be needed, which would reduce contamination from agricultural runoff, prevent overuse of local water tables and lessen the labor and costs placed on growers.
"This is a perfect case to demonstrate how basic science can help the farmers directly," said Ming.