Experiments with factorial arrangements of treatments plus one or more other treatment(s) are sometimes analyzed with a one-way analysis of variance (ANOVA) and means are separated with a multiple comparison. A set of single degree-of-freedom contrasts in a one-way ANOVA, provides formal tests for main effects and interactions. Data from a 2 × 3 factorial experiment that also contained a control were analyzed with a one-way ANOVA with a multiple comparison. Results from this analysis were compared to results obtained from a two-way ANOVA, a one-way ANOVA with pre-planned contrasts, a two-way ANOVA with least squares means comparisons obtained with SAS/general linear models procedure, and a regression model with an indicator variable and random blocks obtained with SAS/Mixed procedure. Results and interpretation differed depending on how the data were analyzed and these differences are discussed.
Frank Schaarschmidt and Lea Vaas
treatment groups was used to compute six orthogonal contrasts defining some hypotheses of interest. The orthogonal contrasts involved the comparison of the control group to the average of all other treatments, two contrasts for the comparisons of the three
Shuyang Zhen and Marc W. van Iersel
generally have greater photosynthetic capacity; i.e., a higher maximum photosynthetic rate and a higher light-saturation point than shade-adapted species ( Björkman, 1981 ). By contrast, shade-adapted species tend to reach maximum photosynthetic capacity at
Feifei Li, Da Zhan, Lixin Xu, Liebao Han, and Xunzhong Zhang
(EverGlade and Kenbule) contrasting in heat tolerance and to examine if variation between the cultivars differing in heat tolerance is associated with antioxidant enzymes and hormone metabolism. Materials and Methods Plant materials and growth conditions. Two
Peter Nveawiah-Yoho, Jing Zhou, Marsha Palmer, Roger Sauve, Suping Zhou, Kevin J. Howe, Tara Fish, and Theodore W. Thannhauser
showing contrasting differences in the two genotypes were selected. Putative roles of those proteins in conferring salt tolerance and the use of those proteins in developing salt-tolerant tomato cultivars are presented. Materials and Methods Plant growth
Xunzhong Zhang, Erik H. Ervin, Yiming Liu, Guofu Hu, Chao Shang, Takeshi Fukao, and Jasper Alpuerto
association of antioxidant enzyme activity and gene expression in cultivars with contrasting drought tolerance would contribute to an enhanced understanding of molecular mechanisms of antioxidant defense systems for drought tolerance of cultivated grasses. It
Johnie R. Schmidt and Josiah W. Worthington
Contrasting colors of plastic mulch (black and white over black) were used to modify the rate at which heat units (HU) were accumulated in four different microclimates surrounding watermelon plants during 1996 at the Texas Agricultural Experiment Station-Stephenville. Daily maximum and minimum temperatures from 25 Mar. through 4 Aug. were recorded for air 10 cm above the mulch surface, at the mulch surface, at the soil surface under mulch, and 10 cm below the soil surface under mulch. Accumulated HU were significantly higher for white than for black mulch during two of the four periods monitored; however, the reverse was true for all other points of measurements at all times. Daily mean soil surface heat gain was 3.29 HU higher under black than under white mulch in early season, 6.21 higher in late April and early May, 5.19 higher in late May and June, and 4.19 higher in late June through July. Values for soil at 10-cm depth paralleled those for soil surface.
Shengrui Yao, James J. Luby, and David K. Wildung
As part of our hardy strawberry (Fragaria ×ananassa) breeding program, winter hardiness of 15 strawberry cultivars was evaluated in the field after Winter 2005–2006 and a test Winter 2006–2007 with no snow cover at Grand Rapids, MN. After the snow-covered Winter 2005–2006, plant stand (percent leaf coverage for the designated area for each plot) increased for all cultivars in the mulched treatment and some cultivars in the unmulched treatment with slight decreases only for several cultivars in the unmulched treatment. However, after Winter 2006–2007, the plant stands of all cultivars drastically decreased in both mulched and unmulched treatments. ‘Clancy’, ‘Evangeline’, and ‘L'Amour’ were the three most sensitive cultivars among the 15 cultivars tested. ‘Kent’, ‘Mesabi™’, ‘Cavendish’, and ‘Brunswick’ were the highest yielding cultivars for both 2006 and 2007 in the mulched treatment. In the unmulched treatment, ‘Brunswick’, ‘Mesabi™ ’, ‘Cavendish’, ‘Sable’, and ‘Kent’ were the top yielding cultivars after Winter 2006–2007. During Winter 2005–2006, with 20 to 30 cm snow cover throughout the season, the 5- and 10-cm soil temperatures remained constant at ≈30 to 31.5 °F in both mulched and unmulched treatments. In contrast, during Winter 2006–2007, there were 16 and 24 days (consecutive) in February below 18 °F at 5-cm soil depths for mulched and unmulched treatments, respectively, which probably led to the severe winter damage. Although straw mulch afforded the plants some protection, snow cover is critical to the survival of strawberries in northern Minnesota and other areas with similar weather conditions.
Andrey Vega-Alfaro, Carlos Ramírez-Vargas, Germán Chávez, Fernando Lacayo, Paul C. Bethke, and James Nienhuis
) to evaluate the yield and flowering time of interspecific graft combinations using sweet pepper cultivars as scions and pungent habanero and aji cultivars as rootstocks in an open field and a high tunnel with soilless media, which are two contrasting
Yali He and Bingru Huang
in two cultivars contrasting in heat tolerance. Materials and Methods Plant materials and growth conditions. The heat-tolerant kentucky bluegrass cultivar Eagleton and the heat-sensitive cultivar Brilliant ( He and Huang, 2007 ) were