Patent Application
20110047636
The present invention relates generally to a system for measuring relative maturity of a crop and, more specifically, to an automated relative maturity system for measuring quickly and efficiently relative maturity of a large number of plants of diverse varieties.
The growing season for agricultural crops varies from location to location. In the United States, the growing season is longer the farther south the crop growing location and shorter the farther north the crop growing location. While there is no standardized maturity zone map, for soybeans, most divide the United States into eleven or twelve maturity zones. Farmers can improve their opportunity for high yields by planting seed of varieties that have maturities adapted to the growing season at the farmer's location. Accordingly, the seed of varieties of most major crops, including corn, rapeseed (or canola), soybeans, sunflower, and wheat, are sold by seed companies primarily into the maturity zone corresponding to the relative maturity of the variety. In the development of novel crop varieties, relative maturity is a critical characteristic that is tracked and measured by the seed companies.
In the past, maturity was measured manually. Workers would walk through fields having multiple plots of varieties under development as the plants neared maturity and, based on a visual evaluation of the plants, come up with a subjective maturity of plants in each of the plots relative to other plants in the field, typically including a number of check plants of known maturity. Collecting data using this method is very time consuming. In addition, despite best efforts, there is inevitably variation in each data collector's subjective evaluation of maturity and also a tendency even among individual data collectors to alter a subjective evaluation of maturity, especially between fields.
There is, accordingly, a need for a high-speed, automated and more objective system for measuring relative maturity of diverse varieties of plants growing in one or multiple fields.
The present invention consists of an automated relative maturity system for measuring the relative maturity of a large number of plots of diverse varieties of plants growing in a field or fields. A field to be evaluated is laid out in multiple plots with a specific variety assigned to a preselected plot or plots and with areas set aside throughout the field for planting of check varieties of known relative maturity. High-precision GPS is used with a planter to record the location of each plot within the field. At a selected time in the life cycle of the crop, preferably when leaf senescence is under way throughout the field, a radiometric crop sensor mounted on a vehicle is used to scan the plants in the plots to record readings of the plants synchronized to the GPS map locations, including the check plants of known relative maturity. Software is used to calculate the relative maturity of each variety. In a preferred embodiment, this relative maturity data is passed on to a database of other characteristics of each individual variety evaluated in the field.
a Photograph of above canopy active sensor method for corn staygreen phenotyping methodology
b Photograph of Corn Staygreen phenotyping methodology below canopy active sensor method
a Graph depicting average staygreen visual readings and active sensor readings across 631 and 641
b Graph depicting average staygreen visual readings and active sensor readings across 631 and 641
a Graph depicting correlation of visual to active sensor readings, peak on week 5
b Graph depicting correlation of hybrid rankings, visual to active sensor, stable for two weeks, 4 and 5
c Graph depicting hybrid −60% visual staygreen is a good indicator for center of two week stable scanning period
d Graph depicting comparison of above and below scanning methods the below good on first date above best and stable for two weeks, 4 and 5
e Graph depicting inbred correlation of visual to active sensor readings, peak on week 5
f Graph depicting correlation of inbred rankings, visual to active sensor, relatively stable for three weeks, week 3, 4 and 5
g Graph depicting inbred 50% visual staygreen is a good indicator for center of three week stable scanning period
Plants absorb and reflect specific wavelengths of light across the spectrum of natural light. The pattern of reflectance and absorbance changes through the life cycle of the plant. Indices comprised of specific wavelengths of reflected energy correlate with the condition of the plant. For example, spongy mesophyll leaf tissue has a high reflectance in the near infrared (NIR) generally defined as the range between approximately 700 and 1000 nm. Since the spongy mesophyll section of the leaf is structurally stable in a healthy leaf and will have a relatively high reflectance in the NIR, whereas the leaf tissue of plants undergoing senescence will have increasingly reduced reflectance in the NIR. The chlorophyll in plants has a high absorbance in the range of between approximately 400 to 500 and 600 to 700 nm, referred to herein as blue and red light, respectively. Accordingly, as the amount of chlorophyll in the plant tissue decreases over time during senescence, the relative absorbance of visual light will decrease.
The apparatus and methodologies described herein utilize radiometric crop sensors that measure the reflectance and absorbance of one or more frequencies of light by plant tissues. There are two types of radiometric sensors, active sensors which use one or more internal light sources to illuminate the plants being evaluated, and passive sensors which use ambient light only. A preferred sensor is the GreenSeeker® RT100 sold by NTech Industries (Ukiah, Calif.) a Trimble Navigation Limited Company, Sunnyvale, Calif. While the sensors disclosed in the preferred embodiments utilize active light sources, so-called passive sensors that utilize ambient light may also be used. Such sensors may be adapted to use visual light, most commonly the red and NIR wavelengths to generate information about the conditions of plants. A commonly used index in assessing crop conditions is the normalized difference vegetative index (NDVI). The NDVI was developed during early use of satellites to detect living plants remotely from outer space. The index is defined as
% NDVI=(NIR−V)/(NIR+V)×100
where NIR is the reflectance in the NIR range and V is the reflectance in the visual range. Preferred sensors for use with the present invention generate an output that is in NDVI units.
The apparatus and methodologies described herein make advantageous use of the Global Positioning Satellite (GPS) system to determine and record the positions of fields, plots within the fields and plants within the plots and to correlate collected plant condition data. Although the various methods and apparatus will be described with particular reference to GPS satellites, it should be appreciated that the teachings are equally applicable to systems which utilize pseudolites or a combination of satellites and pseudolites. Pseudolites are ground- or near ground-based transmitters which broadcast a pseudorandom (PRN) code (similar to a GPS signal) modulated on an L-band (or other frequency) carrier signal, generally synchronized with GPS time. Each transmitter may be assigned a unique PRN code so as to permit identification by a remote receiver. The term “satellite”, as used herein, is intended to include pseudolites or equivalents of pseudolites, and the term GPS signals, as used herein, is intended to include GPS-like signals from pseudolites or equivalents of pseudolites.
It should be further appreciated that the methods and apparatus of the present invention are equally applicable for use with the GLONASS and other satellite-based positioning systems. The GLONASS system differs from the GPS system in that the emissions from different satellites are differentiated from one another by utilizing slightly different carrier frequencies, rather than utilizing different pseudorandom codes. As used herein and in the claims which follow, the term GPS should be read as indicating the United States Global Positioning System as well as the GLONASS system and other satellite- and/or pseudolite-based positioning systems.
For the operation, a tractor or other vehicle is used to tow a planter across the field 10. The planter is fitted with a GPS receiver which receives transmissions from GPS satellites and a reference station. Also on-board the planter is a monitoring apparatus which records the position of seeds as they are planted by the planter. In other words, using precise positioning information provided by the GPS receiver and an input provided by the planter, the monitoring apparatus records the location at which each seed is deposited by the planter in the field 10.
As the tractor and planter proceeds across field 10 to plant various rows of seeds or crops, a digital map is established wherein the location of each seed planted in field 10 is stored. Such a map or other data structure which provides similar information may be produced on-the-fly as planting operations are taking place. Alternatively, the map may make use of a previously developed map (e.g., one or more maps produced from earlier planting operations, etc.). In such a case, the previously stored map may be updated to reflect the position of the newly planted seeds. Indeed, in one embodiment a previously stored map is used to determine the proper location for the planting of the seeds/crops.
In such an embodiment, relevant information stored in a database, for example the location of irrigation systems and/or the previous planting locations of other crops, may be used to determine the location at which the new crops/seeds should be planted. This information is provided to the planter (e.g., in the form of radio telemetry data, stored data, etc.) and is used to control the seeding operation. As the planter (e.g., using a conventional general purpose programmable microprocessor executing suitable software or a dedicated system located thereon) recognizes that a planting point is reached (e.g., as the planter passes over a position in field 10 where it has been determined that a seed should be planted), an onboard control system activates a seed planting mechanism to deposit the seed. The determination as to when to make this planting is made according to a comparison of the planter's present position as provided by the GPS receiver and the seeding information from the database. For example, the planting information may accessible through an index which is determined according to the planter's current position (i.e., a position-dependent data structure). Thus, given the planter's current location, a look-up table or other data structure can be accessed to determine whether a seed should be planted or not.
In cases where the seeding operation is used to establish the digital map, the seeding data need not be recorded locally at the planter. Instead, the data may be transmitted from the planter to some remote recording facility (e.g., a crop research station facility or other central or remote workstation location) at which the data may be recorded on suitable media. The overall goal, at the end of the seeding operation, is to have a digital map which includes the precise position (e.g., to within a few inches) of the location of each seed planted. As indicated, mapping with the GPS technology is one means of obtaining the desired degree of accuracy.
The development of novel varieties of crops typically involves growing a large number of varieties side-by-side in research fields in what are sometimes called preliminary yield trials. A common arrangement is to plant each individual variety in a plot that includes a sufficient number of plants to generate valid data, leaving space between plots for access by workers and field equipment. In a preferred embodiment, the field 10 is divided into a plurality of rectangular plots 12 divided by unplanted rows 14 and 16. To provide a standard or check for the determination of relative maturity, check plots 18 are included. The check plots 18 are planted with varieties of known maturity to be used as a comparison for the relative maturity of plants in the research plots. Preferably, a number of different check varieties are planted to provide a range of maturities to span the expected maturities of the plants in the research plots.
In a preferred embodiment, the field 10 is organized in non-replicated blocks of 2122 plots 12. Most of the plots are planted with experimental varieties of similar parentage and a smaller number of the plots are planted with a selection of different check varieties (
As result of the mapping operation conducted during planting, the latitude and longitude location of each plant in the field 10 is converted into a reference area within each of the plots 12 in the digital map of the field 10, resulting in a map 20 as represented in
As a significant number of the plants in the field 10 reach senescence, the plants in the field 10 are scanned using a radiometric sensor equipped with a high-precision GPS receiver. Each data point collected from the radiometric sensor, which preferably is in the form of an NDVI index, includes latitude and longitude information. The data points are correlated to the location of the plants on the map 20, including the check plots 18. The radiometric data collected from the check plots 18 is used to calibrate the sensor and the collected data from the experimental plots 12. The NDVI data for each plant is then assigned a relative maturity value based on its relationship to the NDVI data from the check plots 18. In a preferred embodiment, the relative maturity data is passed to a comprehensive database of other characteristics of the experimental varieties.
One method of moving the radiometric sensor over the field 10 is manually. A worker simply carries the sensor through the field, holding it above each plant in each plot. A more efficient way of taking the radiometric data is to mount one or more radiometric sensors on a vehicle that then travels the field 10, collecting data on the fly. In a preferred embodiment, a vehicle used for detasseling corn, such as a PDF 450G detassler (Product Design and Fabrication, Cedar Rapids, Iowa) is modified to create a sensor transport 22 (
Applications of Phenotypic Data
The present invention provides methods for generating high through put phenotype data that can be used to characterize plants. This phenotypic data also can be employed in various types of plant breeding and selection including marker assisted breeding. This data can be utilized in analyzing seeds or plant tissue material for genetic characteristics that associate with the relative maturity or stay green phenotype of the individual plants or plants which are genetically related. The genetic characteristics associated with the plant evidencing the presences or absences of the phenotype can be determined by analytical methods. These methods can use markers or genomics data for the detection of chemical, allelic, polymorphic, base pair or amino acid differences.
Samples prepared from the phenotyped seeds or plant materials can be used to establish the desirable genetic attributes that are associated with the selected genotype. Once the selected genotype is identified, it can be used for plant selection thorough out the breeding or selection process. In one embodiment, the methods and devices of the present invention can be used in a breeding program to select plants or seeds having a desired trait, whether genetically modified or native trait or marker genotype associated with the phenotype detected with the high through put relative maturity or stay green data. The methods of the present invention can be used in combination with any breeding methodology and can be used to select a single generation or to select multiple generations or plants or seeds. The choice of breeding method depends on the mode of plant reproduction, the heritability of the trait(s) being improved, and the type of cultivar used (hybrid, inbred, varietal). It is further understood that this device produces phenotypic data for cultivars which can be utilized in a breeding program, in conjunction with selection on any number of other parameters such as emergence vigor, vegetative vigor, stress tolerance, disease resistance, branching, flowering, seed set, seed size, seed density, standability, and threshability etc. to make breeding selections or decisions.
In a particular embodiment, the methods of the present invention are used to determine the genetic characteristics of seeds or plants in a marker-assisted breeding program. Such methods allow for improved marker-assisted breeding programs wherein direct seed or tissue sampling can be conducted while maintaining the identity of individuals from the field. As a result, the marker-assisted breeding program results in a “high-throughput” platform wherein a subpopulation of seeds/plants having a desired trait, marker or genotype can be more effectively selected and bulked in a shorter period of time, with less field and labor resources required.
Two fields were planted on a farm located near Ames, Iowa. Field A was planted on May 21. Field A comprised 21 acres (1920 feet by 480 feet) and was divided into 36,864 plots as shown in
The seed was planted at a density of 10 seeds per foot and a row width 30 inches and a GPS map of the seed planted in the fields was created at the time of planting. Data was collected from Field A on September 2, and from Field C on September 23 and 26 of the same year. Data was collected using the PDF 450G detasseling machine, modified as shown in
The average NDVI for the check and experimental varieties is set out in Table 4.
The data output of the GPS and radiometric crop sensor taken from Field C is set out in Table 5.
The average NDVI for the check and experimental varieties is set out in Table 6.
The NDVI data is correlated to maturity groups by a graph of relative maturity value (RMT_N), determined by the average NDVI for each check variety, versus NDVI. The graph from Field A is shown in
An experiment using the devices shown in
The inbred trial had 1, 30 inch row, 20 foot long plots. The above canopy readings taken over the row, for the first 100 plots. In all the trials, five readings, one per week, were taken. Some frost damage occurred between the 4th reading and last collection date. Average staygreen readings were taken as visual readings and active sensor readings as shown in
In the Inbred Trial a 50% Visual Staygreen was a Good Indicator for Defining the Center of Three Week Stable Scanning Period.
The graphs in
This phenotypic data can be used in a trait mapping experiment to develop genetic characteristics that associate with the phenotype of staygreen. This high through put automated data collection can be utilized in indentifying markers that associate with staygreen phenotypes. The phenotypic data can then be employed in the development of a marker assisted breeding programs. This data can also be captured across time to identify the most critical time for silage production or the prime harvesting timeframes for inbreds or hybrids. This data can be sent from the device to a remote location for analysis of the data. The method of the present invention include capturing the sensor data and analyzing the data for use in phenotyping, marker validation and selection, marker assisted breeding, selections, and producing breeding programs with inbreds and hybrid combination and the seeds and plants and progeny thereof that have the phenotypic traits introgressed through use of the breeding material mapped or selected for relative maturity, staygreen, health, disease, stress, vigor and the like.
The seed was planted at a density of 10 seeds per foot and a row width 30 inches and a GPS map of the seed planted in the fields was created at the time of planting. Data was to be collected from the soybean field for determination of relative maturity. However, prior to the time period for data collection the field was highly impacted by Sudden Death Syndrome (SDS). This disease causes plants particularly those in the R4-R6 stage to die prematurely. Premature death of part of the plants in the field most susceptible to Sudden Death Syndrome would skew any relative maturity ratings. It was determined that data will be collected using the PDF 450G detasseling machine, modified as shown in
The foregoing description comprises illustrative embodiments of the present inventions. The foregoing embodiments and the methods described herein may vary based on the ability, experience, and preference of those skilled in the art. Merely listing the steps of the method in a certain order does not necessarily constitute any limitation on the order of the steps of the method. The foregoing description and drawings merely explain and illustrate the invention, and the invention is not limited thereto, except insofar as the claims are so limited. Those skilled in the art who have the disclosure before them will be able to make modifications and variations therein without departing from the scope of the invention
This application claims benefit of U.S. Provisional Application Ser. No. 61/235,908 filed Aug. 21, 2009 and U.S. Provisional Application Ser. No. 61/349,018 filed May 27, 2010 and U.S. Provisional Application Ser. No. 61/373,471 filed Aug. 13, 2010 which are incorporated herein by reference in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61235908 | Aug 2009 | US | |
| 61349018 | May 2010 | US | |
| 61373471 | Aug 2010 | US |
