cultivars is estimated to range from 60 to 300 kg·ha −1 ( Diczbalis, 2004 ; Tindall, 1994 ). However, results from replicated field trials to evaluate these and other cultivars are very limited. The purpose of this study was to evaluate yield performance
Pumpkins (Cucurbita pepo, C. moshata) were grown in northern Mississippi during 2000 and 2001 for the purpose of more narrowly defining plant population recommendations for commercial production in the humid southeastern United States. Four plant populations were examined for `Aspen': 908, 1361, 2045, and 3068 plants/acre (2244, 3363, 5053, and 7581 plants/ha, respectively) and for `Howden Biggie': 605, 908, 1361, and 2045 plants/acre (1495, 2244, 3363, 5053 plants/ha, respectively). Plant populations were adjusted by varying in-row spacing while holding between-row spacing constant at 8 ft (2.4 m). Plant population significantly affected yield of `Aspen' and `Howden Biggie'. Linear and quadratic terms were significant for `Aspen', with maximum yield (ton/acre and fruit/acre) for the quadratic relationship occurring at about 2045 plants/acre. In contrast, yield of `Howden Biggie' decreased significantly (ton/acre) and nonsignificantly (fruit/acre) in a linear relationship as plant population increased from 605 to 2045 plants/acre. Plant population significantly affected fruit weight and size. As plant population increased, weight and size decreased slightly but significantly in a linear relationship for `Aspen' (lb/fruit and inch3/fruit) and `Howden Biggie' (lb/fruit). The quadratic relationship for `Howden Biggie' (inch3/fruit) was significant and the minimum value occurred at about 1361 plants/acre. Plant population significantly affected pumpkin yield components associated with plant productivity. As plant population increased, number and weight of fruit per plant decreased sharply in a quadratic relationship for `Aspen' (lb/ plant and fruit/plant) and `Howden Biggie' (lb/plant). The linear relationship for `Howden Biggie' (fruit/ plant) also decreased significantly. At the highest plant populations for `Howden Biggie', 40% of the plants did not produce marketable pumpkins. In conclusion, recommendations of optimum plant populations for a semi-vining cultivar such as `Aspen' should be centered on about 2045 plants/acre. Published recommendations from Kentucky appear sound, advocating plant populations within the range of 1360 to 2720 plants/acre (3361 to 6721 plants/ha). For a vining cultivar such as `Howden Biggie', recommendations can be as low as 605 plants/acre. Published recommendations from Kentucky and Georgia, along with those published in the Vegetable Crop Guidelines for the Southeastern U.S., advocate plant populations for vining cultivars of approximately 725 to 1465 plants/acre (1790–3620 plants/ha). Our results with `Howden Biggie', a cultivar that produces larger pumpkins than most other vining cultivars grown for the wholesale market, indicate that producers of vining cultivars should use plant populations from the lowest values of these recommendations or use even lower values. Our results also indicate that growers can control size and weight of pumpkins by varying plant population, with increasing populations resulting in a slight decrease of size and weight.
Declines in cabbage (Brassica oleracea var. capitata) crop quality may result from delaying harvest to allow for greater total yield. An accurate, reliable, rapid and inexpensive method to estimate yield before harvest not requiring direct weight measurements would assist cabbage growers and handlers in harvest scheduling. Results from 3 years of study during which a tool to predict cabbage yield was developed and tested are reported here. The tool was developed using plots containing a total of 13 cabbage varieties (fresh market and processing types) planted in May to July 1999 and 2000 at the Ohio Agricultural Research and Development Center (OARDC) Vegetable Crops Research Branch in Fremont, Ohio. Exhaustive measurement of marketable yield and traits of hundreds of individual heads taken from these plots revealed simple mathematical relationships among head number, size, density, and yield. The tool was tested by comparing marketable yield predicted using a formula based on these head trait relationships to direct measures of crop yield in three different studies: 1) a factorial of nine varieties and 2 planting dates completed in Fremont in 1999, 2000, and 2001, 2) a survey of 12 commercial cabbage fields in northwestern Ohio encompassing six varieties and various planting dates and fertility regimens, in 2001, and 3) a factorial of 32 varieties and 2 planting dates (10 May, 20 June) completed in Fremont in 2001. The R2 for predicted and actual marketable yield in commercial fields and experimental plots ranged from 0.72 to 0.97. Of 510 individual estimatesof marketable yield, 48% were within 10% of actual yield values. The average quotient of predicted divided by actual marketable yield for 510 estimates made for commercial and experimental samples in 1999-2001 was 0.975. Results from this study were applied to the development of a table of potential use to crop managers in obtaining preharvest estimates of cabbage crop marketable yield. The table and its underlying assumptions are easily adjusted for local conditions.
The effect of matric and osmotic seed priming on stand establishment and maturity of broccoli (Brassica oleracea L. var. italica) was investigated in three years at two locations in Virginia. Seeds (`Earlidawn') were primed at 1.1 MPa (68F for 7 days) either osmotically in polyethylene glycol (8000 molecular weight) or metrically in vermiculite (horticultural grade no. 2). In the frost year of the study, seeds were hand-seeded in August into crustprone soil with a mean temperature of 82F, and there were no differences in the percentage or mean time of seedling emergence between osmotic- and matric-primed seeds. Under cooler temperatures during the remaining two years of the study, priming increased the percent emergence and decreased the mean time of emergence by about 15 hours. Primed seeds did not increase yields or accelerate maturity in two out of three years. In the third year, the spread of seedling emergence times was less for primed seeds, which reduced plant-to-plant competition and hastened maturity. The primary benefit of primed broccoli seeds was faster emergence, which increased stands by reducing exposure to stresses that decrease emergence.
The commercial adoption of the relatively new rootstock `Gisela 5' (Prunus cerasus L. × P. canescens L.) has been limited in the United States sweet cherry (P. avium L.) industry despite its ability to induce precocity and productivity and reduce scion vigor compared to the standard Mazzard (P. avium). This is due in large part to inadequate crop load management that has led to high yields of small fruit. This paper reports on sweet cherry chemical blossom thinning trials conducted in 2002 and 2003. Two percent ammonium thiosulphate (ATS), 3% to 4% vegetable oil emulsion (VOE), and tank mixes of 2% fish oil + 2.5% lime sulphur (FOLS) were applied to entire 8- and 9-year-old `Bing'/`Gisela 5' sweet cherry canopies at about 10% full bloom (FB) and again at about 90% FB. In both years, ATS and FOLS reduced fruit set by 66% to 33% compared to the control (C). VOE reduced fruit set by 50% compared to C in 2002 but had no effect in 2003. In 2002, fruit yield was 30% to 60% lower from thinned trees. In 2003, fruit yield was unaffected by thinning treatment. In 2002, ATS and FOLS improved fruit soluble solids but had no effect in 2003. VOE did not affect fruit soluble solids in 2002 and reduced fruit soluble solids by 12%, compared to C, in 2003. In 2002, each thinning treatment nearly eliminated the yield of the small fruit (≤21.5-mm diameter) and increased yield of large fruit (≥26.5 mm) by more than 400%, compared to C. In 2003, ATS and FOLS did not affect yield of small fruit but increased the yield of large fruit by 60%. In 2003, VOE-treated trees yielded 4.3 kg of small fruit per tree compared to about 0.15 kg from C, suggesting a phytotoxic response to VOE beyond that which may effect thinning. Compared to C, ATS and FOLS consistently reduced fruit set and improved fruit quality. We conclude that commercially acceptable yields of excellent quality `Bing' sweet cherries can be grown on size-controlling and precocious rootstocks.
edamame cultivars have been bred for Virginia, few reports have evaluated commercially available cultivar yield potential in the mid-Atlantic United States ( Bhardwaj et al., 1996 ; Sciarappa et al., 2007 ). Virginia and the mid-Atlantic United States
, the objective of these studies was to make carrot cultivar recommendations for commercial production and processing by evaluating carrot root yield and quality characteristics. Materials and methods Study site information. Carrot cultivars were
. 2005, 3 Oct. 2005, 25 Sept. 2006, respectively). Plants that had bolted or exhibited a growth habit different from the remainder of the plot were considered nonmarketable or an off-type and not included in yield data. Yield from individual plots was
study lasting 10 years (5 years of fruit production), Goenaga and Jenkins (2011) found considerable genetic diversity among rambutan cultivars for economically important traits such as fruit production, yield, total soluble solids, and fruit
completely overcome the area's climatic disadvantages. Selection of cultivars that can produce good yields of high-quality bell peppers under these relatively difficult conditions is essential for the commercial success of this crop in northern climates. The