Search Results
Abstract
The rate and total germination of cucumber (Cucumis sativus L.) seeds incubated at 12°C was markedly increased by acetone infusion with fusicoccin (FC). Gibberellic acid (GA4/7) was less effective than FC but more effective than GA3 or (2-chloroethyl)phosphoric acid (ethe-phon) in promoting rapid germination. Infusion of GA4/7 alone or in combination with kinetin and/or ethephon into muskmelon (Cucumis melo L.) seeds increased total germination at 16°C The growth regulators were generally not effective in promoting low temperature germination of watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai) seeds.
Abstract
The rate and total emergence of lettuce (Lactuca sativa L. ‘Empire’) seedlings incubated at 33°C for 10 hr, alternating with 23° for 14 hr, was markedly increased by seed treatment with 0.5 mM fusicoccin (FC). Neither gibberellic acid (GA) nor kinetin (K) were effective in improving emergence when used alone. The combination of FC with GA or K appeared to give a synergistic enhancement of emergence rate. The radicle elongation of seedlings was reduced by seed treatment with FC, K, or combinations of FC, GA, and K in tests at 20°. The greatest reductions were caused by combinations that included FC. The inhibiting effect of FC on radicle growth was reduced by using a concentration of 0.05 mm. Treatment with 0.05 mm FC resulted in slower emergence but gave the same total emergence as 0.5 mm FC at high temperature. Both FC and GA stimulated hypocotyl elongation.
Abstract
(2-chlorethyl)trimethylammonium Chloride (chlormequat) sprayed on tipped Clusters of girdled ‘Cardinal’ grape (Vitis vinifera L.) at 250 to 1000 ppm during bloom increased the number of seeded berries per Cluster but reduced berry weight Heavy Cluster thinning increased berry weight on chlormequat treated Clusters. Succinic acid-2,2-dimethylhydrazide (SADH) did not increase seeded berry set or affect any of the other fruit characteristics measured at the concentrations tested. The synthetic cytokinin, 6-(benzylamino)-9-(2-tetrahydropyranyl)-9H purine (PBA), resulted in a marked increase in seeded berries at 300 ppm, but the number of shot-berries was also increased.
Abstract
Early introduction of honey bees into caged ‘Jersey’ blueberries was associated with increased yields and fruit size and suggests that hives be introduced in plantations for pollination not later than 25% of full bloom.
The results of six experiments conducted over 3 years were analyzed to develop a relationship between nutrient uptake rate and growth rate in hydroponically grown Dendranthema ×grandiflorum (Ramat.) Kitamura, cv. Fiesta. Plants subjected to two levels of CO, and three levels of irradiance in four greenhouses were periodically analyzed for growth and the internal concentration of 11 mineral elements. The resulting data were used to determine relative accumulation rate and relative growth rate, which were included in linear regression analyses to determine the dependence of uptake on growth. The regression equations were significant, with a slight trend toward nonlinearity in some elements. This nonlinearity seems to be related to the aging of the plant and suggests a process in the plant capable of controlling uptake rate, perhaps as a result of changes in the rate of formation of different types of tissues.
Abstract
In the paper “Effect of Plant Population and Planting Date on Root and Starch Production of Buffalo Gourd Grown as an Annual” by J.M. Nelson, J.C. Scheerens, J.W. Berry, and W.P. Bemis [J. Amer. Soc. Hort. Sci 108(2): 198–201, 1983), 2 incorrect quadratic equations are given. In Fig. 3 and on page 199, column 2, line 11, the equation Y = 676 + 0.8X - 0.000072X2 should be Y = 6.8 x 103 + (8.0 x 10-2)X - (7.2 x 10-8)X2. In Fig. 4, the equation Y = 462 + 1.27X - 0.000145X2 should be Y - 4.6 x 102 + (1.3 x 10-2)X - (1.5 x 10-8)X2.
Abstract
The buffalo gourd (Cucurbita foetidissima HBK) produced root yields as high as 34,550 kg/ha with a root starch content of 63.5% on a dry weight basis at a 920-m elevation site. A quadratic relation between root yield and plant population showed maximum yield at 550,000 plants/ha. No clear relation was observed between root starch content and plant population. An April planting resulted in higher root and starch yields than a July planting, at a 370-m elevation site. Vine growth appeared to be restricted when maximum air temperatures were above 40°C.
Agricultural limestone is classified based on particle-size distribution, a key factor influencing neutralization capacity. This property is an effective basis for liming recommendations for agronomic purposes which allow for gradual rise in soil pH and residual neutralization for three years. Inconsistencies are prevalent when agricultural limestone is used for horticultural applications which require rapid attainment of target pH and residual neutralization for only four months. Variations in pH among batches of substrate produced with the same limestone rate and pH drift from the same initial pH during crop production infer that factors other than particle diameter also influence limestone neutralization capacity. In this study the relationship between specific surface and diameter of limestone particles was examined. Limestones obtained from twenty North American quarries were wet-sieved into eight particle diameter fractions from 600 to <38 μm (passing 30 through 400-mesh screens). Specific surface (m2/g) of particles was measured in three replications for each fraction following the BET theory that dinitrogen gas (N2) condenses in a continuous mono-molecular layer on all particle surfaces. At each particle diameter fraction, specific surface varied significantly (five-fold differences) among quarries. Large specific surface may indicate many reactive interfaces, hence high neutralization capacity. In containerized production, typical to horticulture, preponderance of root over substrate mass and short crop duration dictate narrower characterization of limestone than is currently used. Specific surface may describe limestone neutralization capacity more finely than does particle diameter.
Boron deficiency in fresh-market tomatoes (Lycopersicon esculentum Mill.) is a widespread problem that reduces yield and fruit quality but is often not recognized by growers. Tomatoes were grown in field and hydroponic culture to compare the effects of foliar and soil applied B on plant growth, fruit yield, fruit quality, and tissue nutrient levels. Regardless of application method, B was associated with increased tomato growth and the concentration of K, Ca, and B in plant tissue. Boron application was associated with increased N uptake by tomato in field culture, but not under hydroponic culture. In field culture, foliar and/or soil applied B similarly increased fresh-market tomato plant and root dry weight, uptake, and tissue concentrations of N, Ca, K, and B, and improved fruit set, total yields, marketable yields, fruit shelf life, and fruit firmness. The similar growth and yield responses of tomato to foliar and root B application suggests that B is translocated in the phloem in tomatoes. Fruit from plants receiving foliar or root applied B contained more B, and K than fruit from plants not receiving B, indicating that B was translocated from leaves to fruit and is an important factor in the management of K nutrition in tomato.
Plant cold hardiness is a dynamic process, and seasonal changes occur through cold acclimation and deacclimation to help prevent lethal injury from the cold. Cold weather injury resulting from inadequate plant cold hardiness can result in significant economic losses to growers of perennial crops in temperate climates. The objective of the current study was to develop models that estimate the lethal temperature that causes 10%, 50%, and 90% mortality (LT10, LT50, LT90) to two cultivars of sweet cherry (Prunus avium) flower buds from the early fall through to spring. We parameterized regression models using lethal temperature data collected in the Okanagan Valley, British Columbia, Canada, over six seasons (2013–17, 2019–20, 2021–22) for ‘Sweetheart’ sweet cherry and three seasons (2013–15, 2016–17) for ‘Lapins’ sweet cherry. These models incorporate parameters that are based on equations that describe chill and heat accumulation that rely on measures of hourly air temperature. Model evaluation and validation using several seasons of lethal temperature data not included in model development were completed. Models for estimating the cold hardiness of sweet cherry showed good agreement between model lethal temperature predictions and observed values for both sweet cherry cultivars. In addition, an open-access, interactive, web-based application was developed to access the outputs of these models in real time for use by growers, researchers, and extension workers. These current models of sweet cherry cold hardiness have potential application for use as a decision support tool for cold damage management as well as crop site suitability modeling.