Soybean Sudden Death Syndrome Field Screening

Soybean sudden death syndrome (SDS) is caused by the Fusarium virguliforme fungus. This fungus infects and grows in the plant’s roots. The fungus produces a toxin, which is transported into the leaves and causes foliar yellowing, browning, and finally early leaf drop. Root infection and toxin production are highly affected by environment and irrigation, and early planting is important to ensure a good screening test

Within-field Pathogenic Diversity of Phytophthora sojae in Commercial Soybean Fields in Iowa

Phytophthora root and stem rot (PRR), caused by the oomycete Phytophthora sojae, is an economically important soybean disease in the north central region of the United States, including Iowa. Previous surveys of the pathogenic diversity of P. sojae in Iowa did not investigate whether multiple pathotypes of the pathogen existed in individual fields. Considering the many pathotypes of P. sojae that have been reported in Iowa, we hypothesized multiple pathotypes could exist within single fields. In the research reported herein, several soil samples were collected systematically from each of two commercial fields with a history of PRR in Iowa, and each soil sample was baited separately for isolates of P. sojae. Numerous pathotypes of P. sojae were detected from both fields. As many as four pathotypes were detected in some soil samples (each consisting of six to eight soil cores), which suggests that a single soybean plant could be subjected to infection by more than one pathotype. This possibility presents important implications in breeding resistant cultivars and in the management of PRR

Evaluation of Soybean Varieties in the Northern Uniform Soybean Test—Uniform Test III

The Northern Uniform Soybean Test is used to evaluate soybean varieties produced by several public breeding programs in the northern portion of the United States and Canada. In 2010, five public breeding programs participated in the Northern Uniform Soybean Test (Uniform Test III). Public breeders are allowed to enter varieties into the Uniform Test in exchange for growing locations for the test. Material entered into the Uniform Test is generally in advanced stages of a breeding program. The Uniform Soybean Test is a method for soybean breeders to get multiple location data, in a very efficient manner in comparison to each individual program growing their own locations. It also produces useful information by comparing soybean lines from multiple programs, and identifies lines from other states that produce well in southern Iowa. Results from these tests are used by breeders to select varieties with superior yield and/or disease resistance to continue advancement on a trek toward variety release. These results are also used to demonstrate positive characteristics to growers and other interested parties

Evaluation of Soybean Varieties in the Northern Uniform Soybean Test

The Northern Uniform Soybean Test is used to evaluate soybean varieties produced by several public breeding programs in the Northern portion of the United States and Canada. In 2009, five public breeding programs participated in the Northern Uniform Soybean Test (Maturity Group I). Public breeders are allowed to enter varieties in the Uniform Test in exchange for growing locations for the test. Material entered in the Uniform Test is generally from advanced stages of a breeding program. The Uniform Soybean Test is an efficient method for soybean breeders to get multiple location data in comparison to each individual program growing their own locations. It also produces useful information by comparing soybean lines from multiple programs and identifies lines from other states that produce well in northern Iowa. Results from these tests are used by breeders to select varieties with superior yield and/or disease resistance to continue advancement to variety release. These results are also used to demonstrate positive characteristics to growers and other interested parties

Soybean Sudden Death Syndrome Field Screening

Soybean sudden death syndrome (SDS) is caused by the Fusarium virguliforme fungus. This fungus infects and grows in the plant’s roots. The fungus produces a toxin, which is transported into the leaves and causes foliar yellowing, browning, and finally early leaf drop. Root infection and toxin production are highly affected by environment and irrigation, and early planting is important to ensure a good screening test.</p

Evaluation of Soybean Commercial Varieties for Sudden Death Syndrome in Southern Iowa 2015

Sudden Death Syndrome (SDS) is a major fungal disease of soybean in the Midwest. SDS has been found in all counties in Iowa. The large amount of rain in 2015 encouraged SDS foliar symptoms. Yield loss associated with SDS was noted even when foliar symptoms were negligible.</p

La herencia de caracteres agronómicos y la composición química de la semilla en cruzamientos deGlycine max x Glycine soja

Interspecific crosses between the cultivated soybean, Glycine max (L.) Merr., and the wild species. Glycine soja Sieb. &amp; Zuce, may be useful for broadening the genetic base of commercial cultivars. The objectives of the study were to evaluate agronomic traits of G. max, G. soja&nbsp;and their F1&nbsp;hybrids in tropical and temperate environments, to determine whether cytoplasmic effects were present for agronomic traits and seed composition in reciprocal crosses between the two species, and to evaluate the type of gene action that controls the inheritance of traits in interspecific crosses. Reciprocal crosses were made between 'Century' and PI326581 and between 'Amsoy 71' and PI424001. Thirty plants of each of the parents and 50 F1&nbsp;plants of each cross were grown at two environments in Puerto Rico and one in Iowa. The traits evaluated were date of stages R1 and R8, leaf size, shattering, defoliation, vining, lodging, agronomic type, plant height, 100-seed weight, percentage of seed protein and oil, and percentages of palmitic, stearic, oleic, linoleic, and linolenic acids in the oil. No significant differences were observed among environments for seven of the 11 agronomic traits evaluated in the two crosses. The relative performance among genotypes for all traits in Iowa and Puerto Rico was similar. This similarity indicates that it is possible to use tropical locations to evaluate the progeny of interspecific crosses. No significant differences between F1&nbsp;plants of reciprocal crosses were observed in the two crosses for any of the traits; thus, cytoplasmic effects were not important. The type of gene action observed differed among traits and included additive, dominance, and partial dominance.Los objetivos de este estudio fueron evaluar los caracteres agronómicos de G. max, G. soja y sus híbridos F1&nbsp;en ambientes tropical y templado; determinar si en los cruzamientos recíprocos entre estas dos especies hay efectos citoplasmáticos para los caracteres agronómicos y de composición química de la semilla; y evaluar el tipo de acción génica que controla la herencia de los caracteres en estos cruzamientos. Se realizaron cruces recíprocos entre 'Century' y PI326581, y entre 'Amsoy 71' y PI424001. Treinta plantas de cada uno de los padres y 50 plantas F1&nbsp;de cada cruzamiento se sembraron en dos ambientes en Puerto Rico y uno en lowa. Se evaluaron los siguientes caracteres: etapa R1 y R8, tamaño de la hoja, dehiscencia de las vainas, pérdida de hojas, presencia de guías, acamado, tipo agronómico, altura de la planta, peso de 100 semillas, porcentaje de aceite y proteína en la semilla, y porcentaje de los ácidos palmítico, esteárico, oleico, linoleico y linolénico en el aceite. No se observaron diferencias significativas entre ambientes en siete de los 11 caracteres agronómicos evaluados en los dos cruzamientos. El comportamiento relativo de los genotipos para los caracteres evaluados en lowa y Puerto Rico fue similar, lo que indica que es posible usar localidades tropicales para evaluar la progenie de cruzamientos interespecíficos. En cada uno de los dos cruces y para todos los caracteres evaluados, no se observaron diferencias significativas entre las plantas F1&nbsp;obtenidas de los cruzamientos recíprocos, lo que indica que los efectos citoplasmáticos no fueron de importancia. Los tipos de acción génica que se observaron en la herencia de los caracteres evaluados fueron aditivos, de dominancia y de dominancia parcial