Spectral analysis used to compare soybean genotypes
By Doug Rich
The Kansas Soybean Expo, held Jan. 9 in Topeka, Kan., marked the 40th anniversary of the Kansas Soybean Association. A lot has changed in the soybean industry in Kansas during that time period and continues to change as research improves soybean varieties and soybean production methods.
Forty years ago spectral analysis (remote sensing) was generally not part of a meeting about soybean breeding, but today they are linked together in a way that will provide improved soybean varieties for Kansas growers. Bill Schapaugh, who heads the K-State soybean breeder program, explained how he is using spectral analysis in his breeding program.
"We have a team of individuals at K-State that embarked on this project a couple of years ago," Schapaugh said. "To see if it possible to dramatically improve the efficiency of plant breeding and selection using spectral analysis for remote sensing."
In remote sensing, the spectral fingerprints they focus on are the electromagnetic energy emitted from a plant. Many people are familiar with GreenSeeker technology that is used on the field level to help farmers determine nitrogen application rates, particularly in corn and wheat. Schapaugh said with plant breeding they want to bring it down to an even smaller scale than a field.
"We would like to utilize any number of emerging technologies and spectral analysis to capture information on a soybean variety on a small plot or a few square feet out in the field," Schapaugh said. "Hopefully that information would tell us something more or different from the yield data we have collected with the combine or in place of the combine to make the process more cost effective."
At the present time they are using a handheld sensor to collect spectral data on soybean breeding plots. Schapaugh said they don't know exactly what spectral data they need to capture at this point because this technology has not been used in soybean breeding programs before.
"We want to compare genotypes," Schapaugh said. "We want to use the spectral data to tell us something about the performance of a genotype. We want to know if the differences that we can capture with spectral data are related to performance."
So far they have used this technology to develop a computer model for predicting yield on soybean varieties. In the future Schapaugh said they would apply this technology to disease resistance as well.
The update on soybean research at K-State continued with Charles Rice, Ph.D., discussing soybean inoculant trials and tribulations. As soybean acres have spread west across the state of Kansas, there have been problems with nodulation of soybeans.
Rice noted that soybeans are not native to America and the proper bacteria need to be added to the soil when soybeans have not been planted on a field in the past in order to cause the plants to fix nitrogen. Problems with inoculation have been experienced in land that was never planted to soybeans, land that has not been planted to soybeans in over 10 years, and land that is coming our of the Conservation Reserve Program.
"There have been problems over the years with poor nodulation," Rice said.
The problems with inoculants include strain selection, carrier, poor storage, handling, insufficient coverage, and soil or climate conditions. Really dry conditions will kill off the bacteria that are added to the soil.
"The objective of the project supported by the Kansas Soybean Commission is to look at the performance issues with some of these inoculants," Rice said.
Specifically, Rice said they wanted to improve consistency of soybean production, particularly on new soybean ground by addressing nodulation problems and to educate soybean producers and agronomy professionals about proper inoculation techniques and inoculation product effectiveness. Over the last two years they have conducted research at 11 sites around the state.
"We did see an increase in nodule mass but no increase in yield primarily due to the drought," Rice said. "However, even with poor growing conditions we did get some useful data."
Rice said test results showed inoculant products varied in effective nodulation performance and that inoculant product combinations can achieve superior nodulation in ground without established B. japonicum populations. Fields that were part of an established soybean crop rotation did not benefit from inoculant application.
Doug Shoup, Southeast Kansas Extension specialist, concluded the soybean research update with a discussion of soybean fungicides and insecticides. Shoup and Stu Duncan, K-State area agronomist, conducted research that compared seed and foliar application of fungicides and insecticides.
"We can spend money on a lot of different things like fungicides and insecticides but to what extent do I use them, how often do I use them, and and under what conditions do I use them," Shoup said.
Shoup said K-State recommends using fungicide treated seed if the grower is planting soybeans conventionally tilled prior to mid May or planting no-till prior to Memorial Day. Early planted soybeans benefit from seed treatments.
Their research looked soybeans treated with fungicides and insecticides. The test plots included a check with no treatment, ApronMaxx with just fungicides, and CruiserMaxx with both fungicide and insecticides. The research was conducted at 11 different sites with a variety of planting dates.
The test results show a little better plant stands and plant health with seed treatments when compared to the untreated check. There was a small increase in final yield.
Shoup said they also looked at foliar application of insecticides and fungicides. High soybean prices have put a lot of emphasis on high input soybean production to produce the highest yields possible. Whole plant health is the goal of many soybean growers.
"The most consistent yield increases have been seen with stroboilurin fungicides," Shoup said.
The best time to apply these products is at an R3 growth stage. Shoup said the plants are in the early stages of pod formation and late stages of flowering at this time. This means farmers need a separate application to get these products applied at the right time for best results.
"Commodity prices will have a lot of weight on the decision to spray or not to spray," Shoup said. "It is much easier to pay for additional inputs at $15 soybeans than $8 soybeans."
Doug Rich can be reached by phone at 785-749-5304 or by email at firstname.lastname@example.org.