Tue, Apr 18, 2017
by Gregory L. Tylka, Soybean Nematologist, Iowa State University
The ability of soybean cyst nematode (SCN) populations to reproduce on germplasm lines used in soybean breeding programs was originally measured by a test called the SCN race test. Since 2002, an adaptation of the test, called the HG type test, has been in use. Although 15 years have passed since the HG type test was introduced, confusion still exists about the concepts of SCN race and HG type. To help illustrate the concept of HG types, we drew a comparison between the current SCN HG type test and a hypothetical test for human food sensitivities that may provide a new perspective and make HG types more easily understood.
Thu, Apr 6, 2017
by Yuba Kantel and Daren Mueller, Soybean Plant Pathologists, Iowa State University
In our regional field tests we did not find that early planting (first week of May in most locations) increased the amount of SDS that developed later in the season compared to mid-May and later plantings, nor did we find a correlation between soil temperature at planting and SDS development. The soil temperature at the early planting dates had reached 55 to 60° F., the minimum germination temperature for soybean.
Tue, Mar 21, 2017
by Shawn P. Conley, Soybean and Wheat Extension Specialist, University of Wisconsin
A variety is classified to a specific maturity group (MG) according to the length of period from planting to maturity. This phenological attribute is determined by photoperiod and temperature, which can dictate the most suitable MG for a particular geographical location.
Although photoperiod remains constant, climatic conditions, management practices, and soybean genetics have all changed during the past decades. With funding support from the Wisconsin Soybean Marketing Board and the North Central Soybean Research Program, we re-delineated soybean MG adaptation zones across the U.S. using current soybean genetics and climate conditions.
Wed, Mar 8, 2017
By Anne Dorrance, Soybean Plant Pathologist, Ohio State University
Soybean diseases caused by Phytophthora sojae
have been managed successfully for many years with the deployment of single resistance Rps genes as well as partial resistance. However, there are now increasing reports of soybean varieties sold with Rps genes that are no longer effective towards the regional population of P. sojae
or that lack sufficient levels of partial resistance.
Wed, Feb 22, 2017
by Randall Nelson, USDA-ARS, University of Illinois
We crossed cultivated soybean (Glycine max
) with a distant perennial relative, Glycine tomentella
, and were the first to test derived lines. The best line yielded 7 bu/ac greater than the soybean parent, Dwight. We also crossed cultivated soybean with wild annual soybean (Glycine soja
) and identified lines that were equal in yield to the soybean parent, seven days earlier in maturity, yet had 50% of the wild parent DNA based on analysis with DNA markers. This work indicates that very useful yield genes exist in wild relatives of cultivated soybean which are not yet being used in commercial soybean breeding today.
Last season we tested 39 lines that had G. tomentella
as the female parent and thus G. tomentella
cytoplasm and 28 lines with soybean as the female parent with soybean cytoplasm. Averaged over 10 locations, the best line with G. tomentella
cytoplasm yielded 6.1 bu/a more than Dwight and the best line with soybean cytoplasm yielded 6.8 bu/a more than Dwight. To get such high yield increases from soybean × soybean crosses would be notable but to obtain that from backcrosses with the perennial species, G. tomentella
, is extraordinary.
Sat, Feb 4, 2017
by Aaron Lorenz, Soybean Breeder, University of Minnesota
The aim of plant breeding has always been to link phenotype with genotype. Our selections to date are based mainly on phenotype – the yield of a soybean line over many years and locations – so we can be confident that it will perform at that level in farmers’ fields.
Because it is both necessary and expensive to generate this field data, we are putting it to maximum use by also collecting genotypic data of the lines and using it in the selection process. A powerful approach to make use of genomic information for selective breeding is through a method called genomic prediction and selection