Comparison of Yields of Watermelon Varieties Tested in the University of Delaware Trials for Multiple Years
March 8, 2013 in Uncategorized
Emmalea Ernest, Extension Associate-Vegetable Crops; firstname.lastname@example.org
The University of Delaware Extension Vegetable Program has been testing seedless watermelon varieties at the Georgetown Research Farm for more than twenty years. Each year’s trial results are available online at http://extension.udel.edu/ag/vegetable-fruit-resources/vegetable-small-fruits-program/variety-trial-results/. Using the trial reports to determine which varieties performed well in a given year is fairly strait forward, but it is better to base variety selection decisions on more than one year’s data. Since the same varieties do not appear in every trial, making comparisons based on multiple years’ data can be difficult when just looking at the reports.
Yield data for varieties that were tested in more than one of the trials conducted since 2005 is compiled in the table below. Three high yielding varieties that were included in all five of the trials since 2005 are used as standards in the analysis below: Crunchy Red, SS 7187, and Tri-X 313. The other varieties are compared to these standards. For example, Sugar Heart was trialed in three of the five years. Its average yield for those three trials was 60,361 lbs/A. The average yield for Crunchy Red for those same three trials was 73,651 lbs/A. The p-value for the difference between the standard variety and the variety being compared is given in italics below the yield values for the standard varieties. The lower the p-value, the more likely it is that there is a real difference in yield between the two varieties. P-values that are less than 0.05 are considered statistically significant. The p-value for the difference between the yields of Sugar Heart and Crunchy Red is 0.0802, so the yields of these two varieties should not be considered significantly different in the trials.
The three standard varieties were not significantly different than one another in terms of yield for the five years that they were tested. None of the varieties tested had yields that were significantly higher than the standard varieties. Six varieties were not significantly different than the standard varieties and are considered equivalent to the standards in terms of yield: Sugar Heart, Crisp n Sweet, SugaRed, Declaration, SS 7197,and Sweet Delight. Six varieties had yields that were significantly lower than Crunchy Red, but not significantly lower than SS 7187 or Tri-X 313: SS 7167, Liberty, Troubadour, Fascination, Gypsy and Sugar Coat. Melody, Sorbet and Ruby had yields that were significantly lower than all three of the standard varieties. This information can be used to choose varieties that have produced high yields over multiple seasons in our trial. Of course, other important characteristics, such as fruit size, appearance and days to maturity, will also need to be considered when choosing a variety. Information on these characteristics is available in the trial reports.
(Click on the image below for a pdf version of the table.)