Related Papers
HortScience
Potential Uses and Water Demand of Pigeonpeas in Mixed Intensive Horticultural Systems in Dry-subtropical Northwest Mexico
1995 •
Federico Salinas
A water demand model based on the plant–water–climate interactions is proposed to establish the effects of the photosynthetically active radiation (PAR) on the water demand processes of a crop. It is shown that a relationship exists between PAR, leaf temperature, and the transpiration of regional ecotypes of Northwest Mexico from Asia in the middle of the century. These ecotypes were found in the influence area of the Sierra de La Laguna, B.C.S., Biosphere Reserve. Estimated relationship was backed by measurements of leaf and ambient temperatures, and PAR, of which the transpiration is dependent. It is concluded that this procedure is useful to establish the expected level of transpiration of pigeonpeas and thus, their water requirements. The observed phenotype characteristics suggest the usefulness of pigeonpeas in intensive ecosystems; grain yield was near 6 Mg·ha–1. The results enable us to design appropriate horticultural systems in the villages of Sierra de La Laguna, which cou...
HortScience
Preparation and Analysis of Grape Leaf and Petiole Samples by NIR Spectroscopy
Graeme BATTEN
NIR-based tissue analysis has proven useful in Australia for making fertilizer recommendations for rice and wheat growers. Viticulturists have for some time made fertilizer recommendations based on tissue analysis, although there is some debate in the literature as to whether younger or older leaves or petioles provide the best indicator of vine nutrient status for diagnostic purposes. The aim of our research has been to develop NIR-based nutrient analysis for grape producers. Aspects of sample collection, including leaf lamina vs. leaf petiole; leaf opposite the basal cluster vs. youngest leaf; aspects of drying (microwave vs. convection oven), have been reexamined from the viewpoint of convenience, cost, accuracy, and turnaround time with respect to NIR analysis. We have refined procedures for collecting and microwave-drying samples. The samples of leaves and petioles were collected from vines in most wine-growing regions of Australia and included all the major wine grape and some...
HortScience
Grower Contributions to the Early Stages of Crop Nutrient Trials with Vegetables
1995 •
George Hochmuth
Trials to determine crop nutrients for four vegetable crops grown on the limestone soils of Dade County, Fla., have been conducted in growers' fields to duplicate commercial growing conditions. This has increased grower participation in the experimental process. The four vegetable crops are snap beans, Irish potatoes, sweet corn, and malanga (a.k.a. yautia or tannia, Xanthosoma sagittifolium Schott). The discussion will focus on grower participation in various critical decision-making activities: a) location of plots in a commercial field, b) placement of fertilizers, c) possible problems with Restricted Entry Intervals, d) harvest determinations, and e) grading criteria and quality assessment.
HortScience
The Effect of Avocado Clonal Rootstock on Productivity and Tree Vigor of `Hass' Avocado
1995 •
Mary Arpaia
A project evaluating the performance of cv. Hass on eight clonal avocado rootstocks—G755A, G755B, G755C, Duke 7 (D7), Borchard (BR), D9, Toro Canyon, and Topa Topa was established in southern California in 1986. Two additional rootstocks, Thomas and G1033, were added in 1987. Of the trees planted in 1986, the BR and D7 rootstocks have consistently had the highest total yields for all rootstocks, whereas the three G755 selections have had the lowest productivity. No differences in productivity between the two rootstocks planted in 1987 have been detected. The influence of rootstock on the magnitude of alternate bearing will be discussed, although the oscillation in yield is greater for the higher-yielding rootstocks. Tree size has been measured throughout the study. The BR selection has consistently produced a larger tree, even though it has continued to have high productivity. There are no consistent differences between the other rootstocks. Yield efficiency, measured as the kg frui...
HortScience
Changes in Water Relation Parameters in Leaves of Olive (Olea europaea L.) during Salinity Stress and Relief
1995 •
Massimiliano Tattini
Water relation parameters were calculated from analysis of 92 pressure-volume isotherms of leaves of two olive varieties, `Leccino' and `Frantoio', measured after 4 weeks of salinity stress and 4 weeks of subsequent relief either in hydroponics or soil culture. `Frantoio' was more salt-tolerant than `Leccino', but no major differences in water relation parameters emerged between the two varieties. Increasing salinity from 0 to 200 mM NaCl decreased predawn leaf water potential from –0.5 MPa to –1.3 MPa, relative water content (RWC) from 97.6% to 89%, and leaf osmotic potential (Ψπ) from –2.0 to –3.5 MPa. Relative water content at turgor loss point (RWCtlp) was decreased from 89% to 85% (soil culture) and from 86% to 80% (hydroponic culture) in 0 to 200 mM CaCl-treated plants, respectively; a lower RWCtlp was also retained during the relief from salinity. Active osmotic adjustments induced by salinity was the result of accumulation of both inorganic ions and compatibl...
HortScience
Matriconditioning Integrated with GA to Hasten Seed Germination and Improve Stand Establishment of Pepper and Tomato
1995 •
Claudinei Andreoli
Emergence and stand establishment of pepper and tomato seeds often are slow and erratic, particularly under stress conditions. Field emergence trials sometimes have not responded to priming in pepper. In this study, we examined the combining effect of matriconditioning with GA4+7 to hasten germination and improve stand establishment of pepper and tomato seeds. The results showed that, in all cases, even under stressful conditions, the combined matriconditioning plus GA treatment was effective in improving germination and emergence of pepper and tomato seeds. Emergence was improved in 20% when seeds were treated with GA4+7 up to 200 mM. Thus, matriconditioning during which germination is suspended, provides a unique means to rapidly and efficiently digest the endosperm by GA-induced enzymes and reduce not only the mechanical restraints but also provide the energy for embryo growth.
HortScience
The Effect of Salinity on Growth and Physiology of `Hass' Avocado on Three Rootstocks
1995 •
Mary Arpaia
Salinity effects on `Hass' avocado was studied on three rootstocks, `Thomas' (TH), `Toro Canyon' (TC), and `Duke 7' (D7). Four levels of salinity (1.4, 3.0, 4.5, and 6.0 dS·m–1) were applied to 1-year-old trees grown in sand culture for 10 weeks. Increased salinity resulted in decreased trunk cross-sectional area and reduced shoot growth. Specific leaf area and dry weight decreased linearly with increased salinity. TH was significantly more affected than TC of D7. Leaf necrosis was also greatest in TH. Older leaves had the highest percentage of leaf necrosis, while younger leaves of TH exhibited symptoms only in the 6.0 dS·m–1 treatment. TH had the highest Cl leaf levels. TC maintained the lowest Na levels in the scion plant organs, indicating an ability to sequester Na in the rootstock. TC also had the lowest Na:K ratio in leaf tissue, indicating that TC can utilize K as an osmoticum. Predawn xylem potential decreased linearly with increased salinity in all rootstoc...
Hortscience
Dispersal of Perillus bioculatus, a Stinkbug Predator of the Colorado Potato Beetle
1995 •
Conrad Cloutier
HortScience
Copper Sprays—Effects on Apple Fruit Typiness and Market Color Grades
1995 •
Rhoda Burrows
Late dormant copper (Cu) sprays and mid-summer foliar Cu sprays are being promoted within the Washington apple industry as a means to enhance fruit typiness and red skin color, respectively. While there appears to be theoretical bases for these practices, they have not been tested for horticultural significance. Differential late dormant spray treatments of Cu hydroxide (the Cu source most commonly recommended by agricultural consultants) were imposed in two `Delicious' orchards. Flower cluster Cu was positively related to Cu rate, but the sprays had no effect on leaf Cu or on six fruit typiness variables. Differential mid-summer spray treatments of water, Cu sulfate, and Cu oxysulfate solutions were imposed in three `Delicious' orchards and one `Fuji' orchard. The Cu sprays increased leaf Cu, but had no effect on market color grade measured using a commercial color sorter. The results appear to reflect Cu physicochemistry and timing of application. These preliminary res...
HortScience
Effect of Soil Fumigation and Soil Solarization on Annual Hill Strawberry Production
1995 •
Floyd Woods
The use of soil solarization on 20-cm raised beds 30, 60, and 90 days prior to fall planting of `Chandler' strawberries was compared with soil fumigation with 269 kg·ha–1 98/2 methylbromide/choropicrin and with 562 liters·ha–1 metam-sodium (Busan). The clear plastic mulch was painted with white latex paint prior to planting on 15 Oct. Methylbromide/choropicrin treatment gave the best yields, followed by the metam-sodium treatment. Soil solarization on raised beds was complicated by weed growth on the top edges and sides of the bed. Soil solarization is a useful alternative for flat bed culture, but is practically limited on raised beds due to insufficient weed control.
