Plant physiologist Maureen Fitch examines papaya plantlets raised in a petri dish by a process called micropropagation.  Click image for caption and other photo information.

Read the magazine story to find out more.

Replanting Papayas: New Tactics May Cut Costs

The sweet taste and creamy texture of a fresh papaya make this exotic tropical fruit a perfect addition to a zesty salsa, colorful fruit salad or refreshing shake. Or, you may prefer your papaya halved and served with a splash of lime juice.

Scientists with the Agricultural Research Service and their university and corporate colleagues are working out a science-based strategy to streamline today's costly replanting of papaya orchards. They're doing the work in Hawaii at the agency's U.S. Pacific Basin Agricultural Research Center, headquartered in Hilo. Most of America's papaya crop is grown in Hawaii.

Papaya trees bear fruit less than year after they're planted. However, yields typically taper off once trees reach 3 years of age. This means that most papaya orchards have to be replanted every 3 to 4 years, according to ARS plant physiologist Maureen M.M. Fitch at Aiea, Hawaii, near Honolulu.

Fitch has developed a high-tech approach for simpler, less costly replanting. It relies on using shoots from ideal papaya plants to generate multiple laboratory plantlets. Screening all plantlets with a highly accurate laboratory test insures that the plantlets, when mature, will produce trees with the fruit that growers and consumers want.

With this approach, growers need only place one young papaya tree per planting hole in their orchards. That's in contrast to today's practice in which growers must place at least five young trees per hole to insure a 97 percent chance that at least one will produce the desired fruit. The other four trees have to be chopped down, a time-consuming and labor intensive practice.

The idea of propagating perfect papaya plantlets in the laboratory isn't new, but the technology that Fitch is fine-tuning will be freely available, in contrast to proprietary techniques.

Read more about the research in the January 2004 issue of Agricultural Research magazine.

ARS is the U.S. Department of Agriculture's chief scientific research agency.