Registration of soybean germplasm DS1260-2, with improved tolerance to mature seed damage and Phomopsis seed decay

Damage to mature soybean [Glycine max (L.) Merr.] seed occurs when mature seeds are subjected to weathering, fungi, and insects under hot humid conditions. Such damage can be exacerbated by delays in harvest. Mature seed damage (MSD) causes lost revenue to both producers and processors, as well as lower quality of the seed, protein meal, and oil to consumers. The release of DS1260-2 (Reg. no. GP-531, PI 705148) by the USDA-ARS is part of our effort to increase soybean tolerance to mature seed damage using traditional plant breeding. Tolerance to MSD was derived from exotic accession Huang mao bai shui dou (PI 587982A) and incorporated through pedigree selection into an agronomically improved conventional late maturity group IV germplasm adapted for production in the midsouthern United States. DS1260-2 has significantly lower levels of seed damage than cultivars ‘P46T59R’, ‘AG4632’, and ‘P48A60X’, which manifests as lower incidence of Diaporthe longicolla (Hobbs) J.M. Santos (Syn. Phomopsis longicolla Hobbs), less seed coat wrinkling and visual mold, lower incidence of fungal metabolites (nivalenol, cercosporin, cytochalasins H and J, tryptophol, fusaric acid, and beauvericin), and higher seed germination. DS1260-2 yielded similar to P46T59R in trials over 4 years in Mississippi, but less than ‘AG46X6’, ‘AG48X9’, and ‘S16-7922C’ in regional testing. DS1260-2 is resistant to southern stem canker, frogeye leaf spot, and race 3 (HG type 0) of soybean cyst nematode. DS1260-2 is a valuable source for developing cultivars with improved tolerance to the MSD that is caused by mold and weathering.