Integrated management of white mold in soybean

Sclerotinia sclerotiorum, the causal agent for white mold (Sclerotinia stem rot), is a devastating soybean fungal pathogen. In 2006, white mold ranked in the top 10 yield reducing diseases of soybean and was estimated to account for over 2 billion metric tonnes of yield loss world-wide (1). In the United States, soybean losses in 2009 reached an estimated 59 million bushels due to white mold, which cost producers ~$560 million (2, 3). Disease control is limited due to the lack of complete resistance in commercial cultivars and an incomplete understanding of resistance mechanisms (3). Further investigation of white mold resistance mechanisms in soybean and subsequent resistance evaluations of soybean germplasm would improve commercially available resistance

Integrated management of white mold in soybean

Sclerotinia sclerotiorum, the causal agent for white mold (Sclerotinia stem rot), is a devastating soybean fungal pathogen. In 2006, white mold ranked in the top 10 yield reducing diseases of soybean and was estimated to account for over 2 billion metric tonnes of yield loss world-wide (1). In the United States, soybean losses in 2009 reached an estimated 59 million bushels due to white mold, which cost producers ~$560 million (2, 3). Disease control is limited due to the lack of complete resistance in commercial cultivars and an incomplete understanding of resistance mechanisms (3). Further investigation of white mold resistance mechanisms in soybean and subsequent resistance evaluations of soybean germplasm would improve commercially available resistance.</p

Development and Evaluation of Glycine max Germplasm Lines with Quantitative Resistance to Sclerotinia sclerotiorum

Sclerotinia sclerotiorum, the causal agent of Sclerotinia stem rot, is a devastating fungal pathogen of soybean that can cause significant yield losses to growers when environmental conditions are favorable for the disease. The development of resistant varieties has proven difficult. However, poor resistance in commercial cultivars can be improved through additional breeding efforts and understanding the genetic basis of resistance. The objective of this project was to develop soybean germplasm lines that have a high level of Sclerotinia stem rot resistance to be used directly as cultivars or in breeding programs as a source of improved Sclerotinia stem rot resistance. Sclerotinia stem rot-resistant soybean germplasm was developed by crossing two sources of resistance, W04-1002 and AxN-1-55, with lines exhibiting resistance to Heterodera glycines and Cadophora gregata in addition to favorable agronomic traits. Following greenhouse evaluations of 1,076 inbred lines derived from these crosses, 31 lines were evaluated for resistance in field tests during the 2014 field season. Subsequently, 11 Sclerotinia stem rot resistant breeding lines were moved forward for field evaluation in 2015, and seven elite breeding lines were selected and evaluated in the 2016 field season. To better understand resistance mechanisms, a marker analysis was conducted to identify quantitative trait loci linked to resistance. Thirteen markers associated with Sclerotinia stem rot resistance were identified on chromosomes 15, 16, 17, 18, and 19. Our markers confirm previously reported chromosomal regions associated with Sclerotinia stem rot resistance as well as a novel region of chromosome 16. The seven elite germplasm lines were also re-evaluated within a greenhouse setting using a cut petiole technique with multiple S. sclerotiorum isolates to test the durability of physiological resistance of the lines in a controlled environment. This work presents a novel and comprehensive classical breeding method for selecting lines with physiological resistance to Sclerotinia stem rot and a range of agronomic traits. In these studies, we identify four germplasm lines; 91–38, 51–23, SSR51–70, and 52–82B exhibiting a high level of Sclerotinia stem rot resistance combined with desirable agronomic traits, including high protein and oil contents. The germplasm identified in this study will serve as a valuable source of physiological resistance to Sclerotinia stem rot that could be improved through further breeding to generate high-yielding commercial soybean cultivars

Data from: Meta-analytic and economic approaches for evaluation of pesticide impact on Sclerotinia stem rot control and soybean yield in the North Central U.S.

As complete host resistance in soybean has not been achieved, Sclerotinia stem rot (SSR) caused by Sclerotinia sclerotiorum continues to be of major economic concern for farmers. Thus, chemical control remains a prevalent disease management strategy. Pesticide evaluations were conducted in Illinois, Iowa, Michigan, Minnesota, New Jersey, and Wisconsin from 2009 to 2016, for a total of 25 site-years (n = 2057 plot-level data points). These studies were used in network meta-analyses to evaluate the impact of 10 popular pesticide active ingredients, and seven common application timings on SSR control and yield benefit, compared to not treating with a pesticide. Boscalid and picoxystrobin frequently offered the best reductions in disease severity and best yield benefit (P < 0.0001). Pesticide applications (one or two-spray programs) made during the bloom period provided significant reductions in disease severity index (DIX) (P < 0.0001) and led to significant yield benefits (P = 0.0009). Data from these studies were also used in nonlinear regression analyses to determine the effect of DIX on soybean yield. A three-parameter logistic model was found to best describe soybean yield loss (pseudo-R2 = 0.309). In modern soybean cultivars, yield loss due to SSR does not occur until 20-25% DIX, and considerable yield loss (-697 kg ha-1 or -10 bu a-1) is observed at 68% DIX. Further analyses identified several pesticides and programs that resulted in greater than 60% probability for return on investment under high disease levels

2009-16 NETWORK Meta Analysis_Dataset_without Non-treated

2009-16 NETWORK Meta Analysis_Dataset_without Non-treate