NC State Extension

Corn Results – 2013

Comparing Hybrids

Performance of a hybrid 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. The size of chance variation is listed in each table as the L.S.D. (least significant difference) and those hybrids which do not differ by more than the L.S.D. are statistically not different. Those hybrids 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 0.10 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 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 replications. The error degrees of freedom (Error d.f.) used to test varieties or hybrids is listed along with the mean of the test.

The hybrids which 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.
Based on extensive study of the data over 10 years, the most useful data sets to use in choosing medium-maturing corn hybrids are one-year multi-location averages. This one-year average provides the best prediction of the following year performance while including the latest released hybrids. For early and late-maturing hybrids, the two-year averages across locations provide the best data set to examine in choosing hybrids.

Results

Statewide data for early, medium, and late maturity groups for 2013 are presented in Tables 4, 8 and 12; multi-year statewide data are reported in Tables 5 and 9 for medium and full-season hybrids. There was only one multi-year entry in the early maturing category (Augusta A5658GTCBLL), therefore no multi-year comparisons are presented. Multi-year data for Coastal Plain locations are found in Tables 6 and 10; multi-year data for the Tidewater location are found in Tables 7 and 11. Overall it was an above average to average year for corn production in North Carolina, depending on location.

Summary of Data

Table 2. Cultural practices used at each corn test location – 2013.

Table 3. Soil test results, corn – 2013

Table 4. Statewide (North Carolina) average performance of early maturing (105-109) corn hybrids – 2013.

Table 8. Statewide (North Carolina) average performance of medium maturing (110-115) corn hybrids – 2013.

Table 12. Statewide (North Carolina) average performance of late maturing (>115) corn hybrids – 2013

Table 5. Multi-year data combined over locations for medium maturing (110-115) corn hybrids in North Carolina.

Table 9. Multi-year year data combined over locations for late maturing (>115) corn hybrids in (North Carolina).

Table 7. Multi-year data combined over locations for medium maturing corn (110-115) hybrids for Tidewater North Carolina.

Table 6. Multi-year data combined over locations for medium maturing (110-115) corn hybrids for Coastal Plains North Carolina

Table 11. Two-year year data combined over locations for late maturing (>115) corn hybrids for Tidewater (North Carolina).

Table 10. Multi-year data combined over locations for late maturing (>115) corn hybrids for Coastal Plain (North Carolina).

Table B. Individual location data for early maturing (105-109) corn hybrids – North Carolina 2013.

Table C. Individual location data for medium maturing (110-115) corn hybrids – North Carolina 2013.

Table D. Individual location data for late maturing (>115) corn hybrids – North Carolina – 2013.

Table 13. Seed treatment applied to North Carolina OVT corn hybrids – 2013.

NC Measured Crop Performance – Corn 2013
Introduction |Comparing Hybrids |Corn Hybrids |Field Plot Technique | Data |Results |Seasonal Conditions |Cooperators |Sponsors |Corn Silage

Written By

Carrie BrintonResearch Specialist (919) 515-2647 (Office) carrie_brinton@ncsu.eduCrop and Soil Sciences - NC State University
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