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- Author or Editor: Richard C. Funt x
Abstract
Strawberry, Fragaria × ananassa Duchesne ‘Redchief’, plants were grown in single plant-width rows on raised and flat beds at spacings of 13 cm, 50 cm, and 50 cm with runners set at 13 cm. Raised beds had more negative soil water potentials and more variable soil temperatures than flat beds. Plants on raised beds had deeper root distribution, poor runner-plant establishment, higher photosynthetically active radiation (PAR) penetration at one half canopy height in May, and earlier yield than those on flat beds. On raised beds, earliness of yield was enhanced by close spacing, and plants at the 13-cm spacing had more crowns per unit area than wide spacings. Total yield per unit area was not influenced by any treatment.
Abstract
In 1968 and 1970 applications of gibberellic acid (GA) at berry shatter to mature vines of Vitis labrusca L. cv. Concord treated with succinic acid-2,2-dimethylhydrazide (daminozide, SADH) at first-bloom appeared to reduce cluster compactness by lengthening the rachis, to increase berry size, to reduce the number of shot berries, and to increase further the number of mature berries, cluster weight and yield, as compared to daminozide alone. A single application of GA at 50 ppm at berry shatter was as effective in increasing yield as daminozide at 1000 ppm at first bloom, while GA at 100 ppm was significantly more effective. When GA was combined with daminozide were counteracted. The effect of GA on vegetative development was less pronounced than on yield. Highest yield was from the sequential treatment of daminozide 1000 ppm at first bloom and GA at 100 ppm at berry shatter. In the posttreatment year, yields were significantly higher on vines previously treated with either daminozide at 1000 ppm at first bloom, GA at 100 ppm at berry shatter, or daminozide at 1000 ppm with GA at 50 ppm at first bloom.
Physiological disorders of apples, such as cork spot and bitter pit, are a result of low soil calcium, low or excessive soil moisture, large fruit size, and environmental conditions. We report on the effect of microirrigation treatments on apple fruit when irrigation is applied as water alone or water plus a calcium (Ca)/boron (B) solution with applications applied over the tree canopy or under the tree canopy. Apples were harvested from trees in their 4th to 7th leaf and the number of fruit and size of fruit varied from year to year. In most years, there were no significant differences among treatments for fruit Ca. Fruit B was significantly higher in treatments where B was applied through the irrigation. Fruit N/Ca levels were lower when the fruit size was smaller, which was due to a higher number of fruit per tree. Year to year variations in fruit Ca levels also were likely to temperature, humidity, rainfall, fruit size, and shoot growth.
Abstract
Trees of ‘Golden Delicious’, ‘Topred Delicious’, ‘Millersturdeespur Delicious’, and ‘Sundale Golden Delicious’ apple (Malus domestica Borkh.) were grown in two or more of the following orchard management systems established in 1973: slender spindle (SS), 2151 trees/ha, ‘Golden Delicious’ and ‘Sundale Golden Delicious’; trellis (TR), 1121 trees/ha, all cultivars; interstem hedgerow (IH), 795 trees/ha, all cultivars; and pyramid hedgerow (PH), 425 trees/ha, ‘Golden Delicious’ and ‘Topred Delicious’. Yields of ‘Golden Delicious’ in the SS and TR were similar during the first 7 years and these systems generally produced higher yields than the less-intensive systems (IH and PH) during this period. Except for a drop in yield in the TR system in year 10, ‘Golden Delicious’ trees ≥8 years old in all systems produced >50 t·ha−1. ‘Topred’ in the TR system outyielded IH and PH every year, while IH had higher yields than PH in three out of the eight cropping years. The spur-type cultivars Sundale and Millersturdeespur had lower yields per hectare than the standard-habit cultivars because they were spaced too widely. Yields of the systems with ‘Sundale’ generally followed plant density, with the SS being highest, IH lowest, and TR in between and often not significantly different from the other two systems. Orchard management systems had no consistent effects on fruit size. The cumulative yield per hectare of ‘Golden Delicious’ over 11 years grown as SS outproduced the IH and PH systems, with the TR yields intermediate. ‘Sundale’ managed as SS outproduced both the TR and IH systems. ‘Topred’ in the TR had higher cumulative yields per hectare than the PH system. An economic comparison of the ‘Golden Delicious’ systems indicated that PH provided the highest rate of return and the SS the lowest, with the IH and TR systems intermediate.
The performance of peach trees [Prunus persica (L.) Batsch cv. Redhaven/Siberian C.] on raised beds as compared to the conventional flat (unraised) orchard floor surface was evaluated from 1982 to 1991. The raised bed was similar to the flat bed in cation exchange capacity (CEC), Ca, P, K, Mg, B, and Zn soil levels in the 0-15 cm depth. Microirrigation, using two 3.7 L.h-1 emitters per tree vs. no irrigation, was applied to trees planted in a north-south orientation on a silt loam, noncalcareous soil. Raised beds increased trunk cross-sectional area (TCA) and yield-efficiency over 5 years. Irrigation increased fruit mass mostly in years of highest evaporation. Significant year to year variations occurred in yield, fruit mass, TCA and yield efficiency. There were significant bed × year interactions for yield and TCA. Irrigation increased leaf boron content regardless of bed type. Leaf potassium was higher in flat beds. Nonirrigated trees had the lowest tree survival on the flat bed, but the opposite was true on the raised bed.
Calla (Zantedeschia Spreng.) growers were studied as members of an expanding sector in the New Zealand floricultural industry. The calla sector is characterized by diverse-size firms scattered throughout the two main islands of New Zealand. Growers differ in their skill and experience with calla production. Problems are both grower-specific (e.g., control of diseases, postharvest disorders) and sector-wide. Examples of the latter include the prioritizing and funding research, interacting with science organizations and planning sector marketing strategy. Both sets of problems have been exacerbated by the progressive withdrawal of research and extension support services traditionally provided by government agencies. There is competition between the floriculture industry and calla sector-based grower organizations. The leadership role of a strong grower organization, in this case the New Zealand Calla Council (NZCC), is seen as an essential forum for growers, and as the link between growers, exporter organizations, scientists and central government. Good communications between the industry organization and growers is essential to identify and prioritizeproblems and to transfer information to individual growers through workshops, newsletters and manuals. To maintain its effectiveness, the NZCC does not satisfy the needs of smaller growers at the expense of the larger, influential growers. Rather, it seeks to the benefit the latter by upgrading the skill level of the industry, and by undertaking tasks too large for any individual business.
Annual yields of thornless blackberries may be inconsistent due to low winter or early spring temperatures. Under ideal conditions thornless blackberries can produce two or three times more berries per acre and ripen over a longer period of time than the erect, thorny type.
Yields of several thornless blackberry cultivars were improved by using straw mulch. In experiment one standard cultivars were compared to numbered clones. In experiment two Chester, Black Satin, Dirksen and C-65 were compared. Over a six year period, straw increased yields from 1670 to 8300 pounds per acre. Straw mulch appeared to be effective during years where low temperatures did not affect bearing surface.
We investigated the responses of staminate and pistillate floral components of Prime-Jan and Prime-Jim primocane-fruiting blackberry (Rubus L. subgenus Rubus Watson) to three different growth chamber temperature regimens, 35.0/23.9 °C (HT), 29.4/18.3 °C (MT), and 23.9/12.8 °C (LT). Temperature was negatively related to flower size, and morphologically abnormal floral structures were evident in 41% and 98% of the MT- and HT-grown plants, respectively. Anthers of LT- and MT-grown plants dehisced. The viability of pollen (as deduced through staining) from Prime-Jan grown at LT or MT exceeded 70%, whereas that of Prime-Jim pollen was significantly reduced (<40%) by the MT regimen. In vitro pollen germinability (typically <50%) was negatively influenced by temperature but was unaffected by cultivar. Pollen useful life was diminished under HT conditions; LT-grown pollen held at 23.9 °C retained 63% of its original germinability over a 32-h period, while the germinability of that held at 35.0 °C for 16 hours decreased by 97%. Virtually all flowers cultured under HT conditions were male sterile, exhibiting structural or sporogenous class abnormalities including petaloidy and malformation of tapetal cells or microspores; HT anthers that were present, failed to dehisce. Stigma receptivity, pistil density, and drupelet set were also negatively influenced by increased temperature; values for these parameters of floral competency among control plants were reduced by 51%, 39%, and 76%, respectively, in flowers cultured under HT conditions. In this study, flowering and fruiting parameters, and presumably the yield potential of Prime-Jan and Prime-Jim, were adversely affected by increased temperature. However, their adaptive response to heat stress under field conditions awaits assessment.
We investigated the response of staminate and pistillate floral components of Prime-Jan™ and Prime-Jim™ primocane-fruiting blackberry (Rubus L. subgenus Rubus Watson) to three different growth chamber temperature regimes, 35.0/23.9 °C (HT), 29.4/18.3 °C (MT), and 23.9/12.8 °C (LT). Temperature was negatively related to flower size and morphological abnormalities in floral structures were evident in 41% and 98% of the MT- and HT-grown plants, respectively. The viability (stainability) of pollen from LT- and MT-grown Prime-Jan™ flowers exceeded 70%; that of Prime-Jim™ pollen was significantly reduced (<40%) by the MT regime. Pollen in-vitro germinability was negatively influenced by temperature but was unaffected by cultivar. LT-grown pollen held at 23.9 °C retained 63% of its original germinability over a 32-hour period; the germinability of LT-grown pollen held at 35.0 °C was decreased by 97% from its original level after 16 hours. Virtually all flowers cultured under HT conditions were male-sterile, exhibiting structural and/or sporogenous class abnormalities including petaloidy, malformation of tapetal cells, and microspores or failure of dehiscence. The duration of stigma receptivity, pistil density, and drupelet set were also negatively influenced by increasing temperature; values for these parameters of floral competency among control plants were reduced by 51%, 39%, and 76%, respectively, in flowers cultured under HT conditions. Herein, flowering and fruiting parameters and presumably the yield potential of Prime-Jan™ and Prime-Jim™ were adversely affected by increased temperature. However, assessment of their adaptative response to heat stress under field conditions awaits experimentation.