Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/25/2005
Publication Date: 7/14/2005
Citation: Diers, B.W., Arelli, P.R., Carlson, S.R., Fehr, W.R., Kabelka, E.A., Shoemaker, R.C., Wang, D. 2005. Registration of 'LDX01-1-65' soybean germplasm. Crop Science 45:1671-1672. Interpretive Summary: Worldwide soybean yields are primarily limited by a major root parasite, soybean cyst nematode (SCN). In the USA alone, the recent estimate of losses caused by SCN is nearly a billion dollars. Its genetic variability allows the nematode to adapt easily to currently grown resistant cultivars and continue to cause yield losses. It is imperative to identify and utilize new sources of SCN resistance for breeding soybeans for durable resistance and for sustainable soybean production. Soybean germplasm LDX01-1-65 was developed using a wild relative of cultivated soybean called soja, which we identified as resistant to SCN. Most importantly, we found that soja has SCN resistance genes that are not the same as currently used by soybean breeders. Therefore LDX01-1-65 is unique by having rare genetic composition for diversity as well as possessing newer genes for SCN resistance. This unique, combination of traits should improve growers' profits by decreasing losses caused by the nematode. Soybean production will be more sustainable in the USA by utilizing this line as a parent in breeding programs for nematode resistance.
Technical Abstract: Soybean [Glycine max (L.) Merr.] germplasm LDX01-1-65 originated as a BC4 F3 plant selection from back crossing for soybean cyst nematode (Heterodera glycines Ichinohe) (SCN) resistance quantitative trait loci (QTLs) using PI 468916 as a donor parent and the Iowa State experimental line, A81-356022 as a recurrent parent. PI 468916 is a Glycine soja Sieb. and Zucc. plant introduction from People's Republic of China. A81-356022 is a selection from a cross between Century X A76-304020. The two SCN resistant QTL from PI 468916 were mapped to linkage groups (LGs) E and G in a population of F2 derived lines and were confirmed. Three additional backcrosses were made and linked markers were used to select the QTL in each back cross generation. A single BC4 F1 plant was selfed and single seed descent (SSD) was used to develop a population of BC4F3 derived lines. This population was bioassayed at USDA-ARS, Jackson, TN with PA3, a HG type O SCN population and was reconfirmed for resistance. Agronomic traits were evaluated in three Illinois environments and two environments at USDA-ARS, Jackson, TN during 2003. Across environments, LDX01-1-65 had 255 kg/ha greater yield than A81-356022. The yield for A81-356022 soybean was 2176 kg/ha. LDX01-1-65 is late group III maturity with an indeterminate growth habit. It has purple flowers, tawny pubescence, brown pod color at maturity, and yellow seeds with black hila. LDX01-1-65 has value as a parent in soybean improvement in the USA especially in broadening the diversity of SCN resistance genes since they map to unique genetic regions not currently being used by breeders.