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Soybeans 2013 Introduction

NORTH CAROLINA

MEASURED CROP PERFORMANCE

COTTON AND SOYBEAN 2013

North Carolina State University
College of Agriculture and Life Sciences
North Carolina Agriculture Research Service
Raleigh, North Carolina 27695
Steven Lommel, Director of Research
Crop Science Research Report No. 242
December, 2013

Introduction

With the large number of commercially available and prospective hybrids and varieties of soybean, it becomes difficult for growers to select a superior variety suited for their particular area of the state and their individual farming operations. To make this decision, the growers need up-to-date, unbiased, reliable information. The Official Variety Testing Program, through this report, seeks to provide that type of information.

The first section of this report is concerned with cotton and the second section deals with soybean. Both sections are complete in that they contain information on experimental procedure, location of the tests, a discussion of the data for 2013, as well as summary tables for the past two and three years.

It is hoped that the organization of this bulletin will provide data in a complete form to those interested in these two crops.
Growers are cautioned against making varietal selection decisions based on an individual location in any one year. True varietal performance may have been masked by the unusual weather conditions experienced at any one location or any one growing season.

Comparing Hybrids and Varieties

Performance of a hybrid or variety cannot be tested with absolute
precision. Although the tests are conducted in a uniform manner, as much as possible, uncontrollable variability exists among experimental plots due to soil type, fertility, moisture, insects, diseases, and other sources of variation. Because this variability exists, statistics are used as a tool to determine differences among hybrids and varieties. The size of difference among hybrids or varieties, which may have been due to chance variation, is listed in each table as the L.S.D. (least significant difference).

Those hybrids or varieties that do not differ by more than the L.S.D. are statistically not different. Those hybrids or varieties that do differ by more than the L.S.D. are statistically different. The Bayes L.S.D. at the K-ratio of 50 (approximately .10 level of probability) was used.

The coefficient of variability (C.V.) is listed as a general indicator of population variability; it does not, however, always indicate level of precision. The coefficient of determination (R2) is a better measure of the level of precision because it indicates the amount of variation accounted for in the trial. The higher the R2 value the more precise the trial. Thus, relative precision among various trials can be compared. The standard error of the mean (s.e.) is also listed as a general indicator of precision since it reveals how well the true mean was estimated. The formula for the s.e. is the square root of the error variance divided by the square root of the number of replicates. The error degrees of freedom (Error d.f.) used to test hybrids and varieties is listed along with the mean of the test.

Hybrid or varietal performance may appear inconsistent among locations within an area or among years in a particular area, thus it is important for the reader to examine results from more than one location or more than one year at a particular location to obtain a more accurate picture of relative hybrid or varietal performance. An effort has been made to facilitate comparisons across locations and across years in this report.

The hybrids or varieties that do not yield significantly less than the highest yielder are denoted by an asterisk (*) next to their yields; the highest yielder is denoted by a double asterisk (**) next to its yield. Other agronomic characteristics may be as equally important as yield.

It is suggested that the grower plant a small number of acres in a new hybrid or variety when first determining if it is adapted to his/her farm. Research conducted at North Carolina State University and several other universities has consistently shown a significant yield advantage where professionally grown/certified seed is used rather than “farmer saved” or “brown bagged” seed. These tests were planted with professionally grown/certified seed provided by the
sponsoring agencies. Farmers who use inferior seed sources can expect accompanying decreases in performance.

Seasonal Conditions

Planting for all trials was delayed for early-planted and late-planted tests due to wet soils (Table 12). The season was characterized with above average rainfall at all locations throughout the growing season. Harvest was delayed at all locations due to continual wet conditions (Table 12).

Columbus County was discarded due to excessive rainfall. Various locations received an excessive amount of rainfall resulting in low yields. (Refer to weather graphs at end of bulletin.)

Due to higher than normal rainfall through June and continued wet conditions into July, the late planting at Lenoir was delayed until July 22nd. In addition, this location was affected by lack of precipitation through September and October. (Refer to Lenoir weather graph at end of bulletin.) First frost (10/26/13) and killing frost (11/13/13-11/15/13) at our Lenoir site did not come earlier than normal; however, due to growing conditions this season, could have occurred prior to physiological maturity. Data from this location were included in the dataset as a useful tool for farmers that may be faced with weather-delayed plantings in the future.

Test Locations

Five full season tests were located in the Coastal Plain with another test in the Piedmont. Three late planted tests were located in the Coastal Plain and one test in the Piedmont.

Data

Data were collected on yield, moisture, lodging, pod maturity, and plant height. Yields were calculated on plot weight and adjusted to 14% moisture. Lodging was scored on a scale of 1-5 with “1” being no lodging and “5” being completely lodged before harvest; this does not necessarily reflect harvest loss. Plant height was determined by measuring from the ground to the top of the plant prior to harvest.

Results

Soil test results are shown in Table 13. Roundup ready and conventional beans were separated. Data for conventional varieties are shown by maturity group with maturity group IV in Table 14 and Table 15, maturity groups V early and late in Tables 16, 17, 18 and 19, maturity group VI in Tables 20, 21 and maturity groups VII-VIII in Tables 22, 23.
Roundup-ready variety data are shown in Tables 24-25 (group IV), 26-27 (early group V), 28-29 (late group V), 30-31 (group VI), and 32-33 (groups VII-VIII). Table 34 lists the seed treatments used by various sponsors.

Interpreting Data

Research has shown that the best data to use in selecting varieties are two-year multi-location data, e.g. Tables 14, 16, 18, 20, 22, 24, 26, 28, 30 and 32. Data were good in terms of precision at locations reported. There was a strong variety by location interaction for Group 5 late conventional, Group 6 conventional and Group 5 late, Group 6, Group 7-8 roundup ready varieties.

R2 were higher for conventional beans 85 to 92 versus 66 to 89 for roundup ready beans.

Individual location data should not be used to make varietal selections.

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