New ARS-developed soy line resists key nematode

New soy line JTN-5109 developed by Agricultural Research Service (ARS) scientists is effective against LY1, the most virulent soy cyst nematode.

The soy cyst nematode is a pervasive soy pest worldwide. In the US, the nematode is the most damaging soy pest, causing an estimated yield loss of nearly 94 million bushels in 2007. Genetic resistance has been the most effective means of controlling the pest.

Nearly all nematode-resistant soy varieties currently available contain resistance genes from one of two sources--soy lines ''Peking'' or Plant Introduction (PI) 88788. JTN-5109, however, has combined nematode resistance from three sources -''Peking,'' PI 437654 and PI 567516C. JTN-5109 was developed using a combination of traditional plant breeding and genetic marker-assisted selection.

Nematode populations are genetically variable and have adapted to reproduce on resistant soy cultivars over time. And in recent years, the LY1 nematode populations were found in Missouri, Illinois and Tennessee.

JTN-5109 provided yields of 26 bushels per acre in field studies conducted in 2008 at Jackson, Tennessee, and Ames Plantation near Grand Junction, Tennessee. That yield is not far below the 29 bushels per acre produced by 5601T, which is a commonly used cultivar, but one susceptible to LY1. The JTN-5109 line will be an excellent source material for breeding high-yielding soy with resistance to nematodes, especially for the LY1 nematode population.