New garden- and dry-pea breeding lines developed by U.S. Dept. of Agriculture (USDA) scientists and their collaborators may offer growers added insurance against Aphanomyces root rot, a disease that can cause crop yield losses of 20–100%.
The mold-like pathogen that causes the disease, Aphanomyces euteiches, infects the roots and underground stems of susceptible pea plants and other legumes, rotting them and causing stunted growth, lesions, wilted leaves, and other symptoms. Fungicides aren't an option, so growers must either avoid planting in fields with a history of the disease or switch to growing non-host crops until pathogen numbers drop to acceptable levels.
As an alternative, USDA Agricultural Research Service (ARS) scientists sought to develop pea germplasm lines that naturally tolerate the pathogen, but do not suffer the same ill effects as susceptible plants—particularly not significant yield losses. The pea lines are descendants of an inbred population of plants derived from an ARS cross made in 1993 between the cultivar Dark Skin Perfection and germplasm line 90-2131. Besides their tolerance of Aphanomyces root rot, the lines were also chosen for their acceptable agronomic characteristics.
Incorporating the tolerance trait into elite varieties could prove especially beneficial to growers in Pacific Northwest and North Central states, where Aphanomyces outbreaks threaten the valued role that peas and other legumes play in cereal-based crop rotation systems.