Hybrid Bell Pepper Is Latest Bad News for Nematodes

Nematode-resistant varieties of hybrid bell peppers may soon offer desirable characteristics possessed by nonresistant types. This is because Agricultural Research Service scientists at the U.S. Vegetable Laboratory in Charleston, S.C., have bred an experimental hybrid that inherits its resistance from just one of its parent varieties.

Nematodes are microscopic roundworms that cause millions of dollars in annual damages to crops nationwide. Root-knot nematodes are a major problem for bell pepper growers.

The hybrid, developed for research purposes by plant pathologist Judy A. Thies and geneticist Richard L. Fery, shows that nematode-resistant bell pepper hybrids can be developed by crossing a resistant, open-pollinated bell pepper type with varieties lacking the key resistance gene but possessing other positive characteristics such as large fruits or resistance to disease. The new hybrid is as resistant as hybrids developed by crossing two resistant pepper varieties.

The hybrid marks the latest success from ARS research in nematode-resistant bell peppers at the Charleston laboratory. In 1997, Fery released Charleston Belle and Carolina Wonder, the first bell peppers resistant to root-knot nematodes.

Those peppers' resistance stems from what is called the N gene, which Fery obtained from Mississippi Nemaheart, a pimiento pepper variety that carries the resistance gene. The gene controls resistance to three major root-knot nematode species: Meloidogyne incognita, M. arenaria and M. javanica.

The experimental hybrid was developed by crossing the resistant Charleston Belle with Keystone Resistant Giant, which lacks the N gene.

Progress with nematode-resistant crop varieties is significant because the soil fumigant methyl bromide, the primary control method now used to combat the parasites, is scheduled to be banned in 2005 because of its negative effects on the ozone layer. A 1995 economic study declared that banning methyl bromide without an alternative method of controlling nematodes would cost the nation's bell pepper industry $127 million in losses.

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