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- Author or Editor: Timothy E. Elkner x
Medium-sized triploid watermelons were evaluated in southeast Pennsylvania in 2002 and 2003 to determine the best adapted cultivars for this region. The 2002 season was unusually hot and dry, while 2003 was unusually cool and wet. Yields and fruit quality were compared for the eight cultivars that were grown both seasons to determine the effect of weather on seedless watermelon. Cooler temperatures reduced total fruit number and total yield but not average fruit weight or soluble solids. Researchers evaluating triploid watermelons over several seasons can compare size and °Brix among cultivars, but will need to be cautious when predicting total yields.
Abstract
One of the most important aspects of designing an experiment is determining sample size. Without prior experience, estimation of the amount of variation that will be encountered during data collection is difficult. This information is necessary to decide the number of replicates needed. Recently, Marini (1985) and Marini and Trout (1984) have published reports on the sample size needed to determine treatment effects in peach tree growth and yield studies. However, this type of information is lacking for sample sizes required to detect differences in net photosynthesis in peach. This note attempts to assist researchers in determining correct sample size.
Abstract
The effects of BA alone or in combination with GA4+7 and with either daminozide or a surfactant on growth and lateral development of peach [Prunus persica (L.) cv. Redhaven] were evaluated at 4 stages of terminal growth. BA + GA4+7 at 500 ppm or 1000 ppm daminozide was the most effective treatment for inducing lateral development when applied at terminal growth of 15-20 cm or 31-36 cm. BA + GA4+7 increased both tree height and average internode length for all treatments. BA with either surfactant or daminozide was not effective in inducing lateral shoot formation and caused shorter internodes and retarded tree growth in all treatment combinations except 250 ppm + 1000 ppm daminozide. Chemical names used: N-(phenylmethyl)-1H-purin-6-amine (BA) and (1α,2β,4aα,4bβ,10β)-2,4a,7-trihydroxy-l-methyl-8-methylenegibb-3-ene-l,10-dicarboxylic acid 1,4a-lactone (GA4+7).
Texas Tech Univ., in collaboration with the Texas Agricultural Experiment Station, Lubbock, maintains a research vineyard at Brownfield. Texas. Thirty-one wine-grape varieties are being evaluated for performance on the Texas High Plains. The vines were planted on their own roots in a completely randomized design with four replications and two plants per replication. The average rainfall, including supplemental irrigation, was ≈550 mm/year. Sufficient data exist for comparison of 18 varieties during the 1992–1994 seasons, following a severe freeze in Nov. 1991. The vines were trained to a horizontal bilateral cordon and spurpruned with two buds per spur and 10 to 12 spurs per vine. Pruning weights were taken from the surviving vines during the 1993–1995 dormant seasons. Pruning weights were used as a direct estimate for plant vigor. The varieties exhibiting lowest vigor included `Carmine', `Pinot Blanc', `Pinot Noir', and `Ruby Cabernet', while those exhibiting highest vigor included `Semillion', `Chenin Blanc', `Muscat Canelli', and `French Columbard'.
Fruiting spurs (`Red Prince Delicious') (RD) and shoots (`Sundale Spur Golden Delicious') (CD) with three leaf:fruit ratios and comparable nonfruiting spurs and shoots were girdled on 7 September 1988. An interaction between fruiting status and time existed for most parameters measured on both cultivars while there was no effect of leaf:fruit ratio. At 1 day after treatment (DAT) few differences existed due to fruiting status on either cultivar. At 8 DAT with RD and at 4 and 8 DAT with GD, Pn, transpiration (Tr), leaf water potential (ψ L), and nonreducing sugars were greater on fruiting than nonfruiting spurs and shoots while leaf resistance (RL), SLW, and starch were lower on fruiting spurs. In nonfruiting spurs and shoots Pn, Tr, and ψL tended to decrease while RL and SLW increased with time whereas m fruiting spurs and shoots most parameters remained constant. Total nonstructural carbohydrates, reducing sugars, and starch were greater in nonfruiting than fruiting spurs and shoots.
Sixteen cultivars of green bell peppers (Capsicum annuum) were evaluated on the basis of yield in three locations across Pennsylvania during the growing seasons of 2008–09. Cultivars were evaluated in comparison with the cultivar Paladin. In central Pennsylvania, all the cultivars trialed had marketable yields (based on weight) not different than ‘Paladin’ except ‘Lynx’, ‘Socrates’, and ‘Escape’. In terms of fruit number, all cultivars were not different than ‘Paladin’ except ‘Socrates’. For large-sized fruit, all the cultivars trialed are recommended. In southeastern Pennsylvania, all the cultivars trialed except SP-05–47 had marketable yields not different than ‘Paladin’. For large-sized fruit, ‘Revolution’ outperformed all other cultivars, including ‘Paladin’. In southwestern Pennsylvania, all the cultivars trialed except Lynx and SP-05–47 produced comparable marketable yields to ‘Paladin’. None of the cultivars evaluated, including Paladin, consistently outperformed Revolution in terms of large fruit. Statewide, all the cultivars, except Lynx and SP-05–47, are recommended on the basis of marketable yields. For growers looking for large-sized fruit to meet market demand the cultivar Revolution is recommended over ‘Paladin’.
Butternut, acorn, and buttercup/kabocha winter squash (Cucurbita sp.) cultivars were evaluated in a conventional system in central, southeastern, and southwestern Pennsylvania in 2010–11. Results from individual locations were used to create statewide recommendations, which are also relevant for the mid-Atlantic U.S. region. Additionally, butternut and acorn cultivars were evaluated in an organic system in central Pennsylvania. In a conventional system, butternut cultivars JWS6823, Betternut 401, Quantum, and Metro are recommended based on equal or higher marketable yield than the standard Waltham Butternut. Acorn squash cultivars that performed equally to or better than the standard, Tay Belle, were Table Star, Harlequin, and Autumn Delight. In the kabocha/buttercup category, ‘Sweet Mama’ and ‘Red Kuri’ had marketable yields not different from the standard ‘Sunshine’ in central and southeastern Pennsylvania. In the organic system, butternut cultivars JWS6823, Betternut 401, and Metro all had marketable yields not different from the standard Waltham Butternut. For acorn cultivars, Celebration yield did not differ from the standard Table Queen.
To provide growers with regional and statewide recommendations, 23 cultivars of bicolor and white synergistic sweet corn (Zea mays) were evaluated in southwestern, central, and southeastern Pennsylvania. ‘Temptation’ was the standard. Despite differing production practices used in all locations, all cultivars were not different or produced more marketable primary ears compared with Temptation. Paydirt was the only cultivar to produce lower marketable yields by weight than Temptation in 2 site years or more. However, ‘Paydirt’ has an early maturity, which improves its acceptability. Very few ears were unmarketable. In terms of ear size, measured as diameter and length, overall all cultivars were not different from Temptation. ‘Temptation’ is early maturing and ear size was expected to be smaller than later maturing cultivars. This was not observed. Ease of hand harvesting was determined by measuring two factors: distance from the base of the primary ear to the soil line and ease of picking (1–5 rating scale where 1 = difficult and 5 = easy). The closer the primary ear was to the soil line was thought to be more difficult to harvest. ‘Synergy’, ‘Espresso’, ‘Kristine’, and ‘Paydirt’ ears were lower than ‘Temptation’ on the culm in 2 site years or more. ‘Whiteout’, ‘Synergy’, and ‘Mattapoisett’ were rated as more difficult to pick than ‘Temptation’ in 2 site years or more. Distance from the soil line to the primary ear and picking ease ratings were not observed to be closely related to each other and a combination of these and other factors may more accurately reflect the ease of hand harvesting. Overall, growers in our region have access to a lot of synergistic sweet corn cultivars with acceptable yield, quality, and ease of hand harvesting characteristics giving them a wide range of options.