From 1988 to 1990, the fall fruiting raspberries Heritage, Perron Red, Autumn Bliss and 3413-12 were field evaluated under two cultural systems: conventionnal production and production under plastic tunnel. The plastic tunnel was in place over 4 rows from early September to late October without supplemental heating. Compared to the conventionnal system, the tunnel contributed to a lengthening of 1 to 4 weeks in the fruiting period 2 years out of 3. In spite of the higher day temperatures, the rate of fruit ripening was not increased under the tunnel but fruit size was increased slightly. However, the latter did not translate in higher yield per day since fruit number decreased under the tunnel. Total yield increased only one year when the first killing frost occurred a full month before the second one. Generally, night temperatures were as low in the tunnel as those outside.
Michel Lamarre and Michel J. Lareau
over traditional summer-fruiting, floricane raspberries. Most notably, they provide an opportunity to extend the season from late summer into fall. Whereas the summer raspberry harvest lasts ≈6 weeks, fall fruiting can add an additional 6 weeks or
Jean-Pierre Privé and J. Alan Sullivan
Growth rates for two types of tissue-cultured plant stock for `Heritage', `Ruby', and `Redwing' red raspberry (Rubus idaeus L.) were examined. Actively growing plantlets from the greenhouse (G) were compared to cold-treated (CT) plantlets from cold storage. The greatest differences between these two occurred during the first 6 weeks after planting. At 4 weeks, CT plants for all cultivars had longer canes and internodes, sometimes twice that of G plants. Although `Heritage' had greater total plant dry weights following chilling, `Ruby' and `Redwing' had less. Chilling had no effect on `Heritage' root growth but did reduce root dry weight for `Redwing' and `Ruby'. Relative growth rate (RGR) and leaf area ratio (L-AR) were more effective variables for analyzing growth as they considered differences in initial biomass and cane number and provided a better representation of the data during the initial 6 weeks of growth. All cultivars showed a greater total plant RGR and LAR for the CT plants at 6 weeks. During the first 4 weeks, the G plants were more efficient producers of root dry matter while the CT plants were more efficient producers of cane dry matter. By 6 weeks, the G plants had partitioned a greater percentage of their assimilates into cane growth while the leaves, canes, and roots of the CT plants contributed equally to total RGR. No difference in total or individual component RGR was observed after 6 weeks.
James R. Ballington, Barclay Poling, and Kerry Olive
South Carolina. In Tennessee, Straw (2005) has investigated the potential of fall fruiting of ‘Sweet Charlie’ (SD type), along with 2 DN strawberry cultivars (Everest and Seascape) at the Plateau Experiment Station near Crossville, but problems were
Christine M. Bradish, Gad G. Yousef, Guoying Ma, Penelope Perkins-Veazie, and Gina E. Fernandez
of environmental protection between field and greenhouse production systems ( Kadir et al., 2006 ; Heidenreich et al., 2008 ). Most high tunnels in the United States and Canada are used for fall-fruiting primocane cultivars to extend the harvest
The effect of fruit on shoot growth, leaf area, and on dry weight (DW) partitioning into leaves, fruit, trunk, and branch sections was investigated using 7-year-old `Lambert' sweet cherry (Prunus avium L.) trees. Dormant trees were sampled in the spring, and fruiting and deblossomed trees were sampled and compared at fruit harvest and just before leaf fall. Fruiting reduced shoot growth, leaf area, and above-ground DW accumulation of the trees. The annual above-ground DW accumulated was 13.4 kg for fruiting trees and 16.0 kg for nonfruiting trees. The greatest proportion of above-ground DW was partitioned to wood, whereas the least was partitioned to fruit. Current-season's growth (wood and leaves) appears to be a greater sink for photosynthates than is fruit because a greater proportion of above-ground DW was partitioned to current-season's growth than to fruit.
Kim E. Hummer, Les H. Fuchigami, Vonda Peters, and Neil Bell
Stem and bud tissues of promocanes from more than 260 Rubus genotypes were evaluated for mid-winter cold hardiness after laboratory freezing in January 1990. T50 values were calculated for cane samples of red, yellow, black and purple raspberry, and blackberry cultivars, hybrids and species. Red raspberries exhibited the hardiest stem tissue, although several purple raspberries (Rubus sp. cvs. Brandywine, Royalty) survived as low as -33 C. Fall fruiting red raspberries, such as R. idaeus L. cvs. Zeva Remontante, Indian Summer, St. Regis, and Fallred, survived from -23 to -25 C. Summer-bearing cultivars, Canby and Puyallup, survived to -30 C. Stems of several black raspberries (R. occidentalis L. cvs. New Logan, Bristol) survived to -27 C. Stems of the hardiest blackberry cultivars, (R. sp. cvs. Black Satin, Smoothstem) survived to -22 C. In most genotypes the region of the bud at the axis of the stem was less hardy than tissues within the bud scales. Buds tissue was 2 to 10 C less hardy than stem tissue. Field plants were also visually rated for cold injury following record low temperatures occurring in 1989, 1990, and 1991.
C. Jasso-Chaverria, G.J. Hochmuth, R.C. Hochmuth, and S.A. Sargent
Two greenhouse cucumber (Cucumis sativus) cultivars with differing fruit types [European (`Bologna') and Beit-alpha (`Sarig')] were grown during two seasons in a perlite medium in black plastic nursery containers in a passively ventilated greenhouse in northern Florida to evaluate fruiting responses to nitrogen (N) fertilization over the range of 75 to 375 mg·L–1. Fruit production, consisting mostly of fancy fruits, increased quadratically with N concentration in the nutrient solution, leveling off above 225 mg·L–1 for both cucumber cultivars. Fruit length and diameter were not affected by N concentration in the nutrient solution. Leaf N concentration, averaged over three sampling dates, increased linearly with N concentration in the nutrient solution from 46 g·kg–1 with 75 mg·L–1 N to 50 g·kg–1 with 375 mg·L–1 N. Fruit firmness decreased with increasing N concentration and there was little difference in firmness between the two cultivars. Firmness was similar across three measurement dates during the spring harvest season, but increased during the season in the fall. Fruit color responses to N concentration were dependent on the specific combination of experiment, sampling date, and cultivar. For most combinations of experiment, sampling date, and cultivar, cucumber epidermal color was greener (higher hue angle) with increased N concentration. The color was darkest (lowest L* value) and most intense (highest chroma value) with intermediate to higher N concentrations.
S. Pérez, S. Montes, and C. Mejía
A wide range of peach [Prunus persica (I,.) Batsch] germplasm was collected from the most important peach growing regions in Mexico and some Latin American countries, as well as from breeding programs in the United States, Europe, and South Africa. Budded trees, seedlings derived from selfing cultivars and selections, and seed samples from various growing regions were propagated and planted in central Mexico. Twenty eight morphological or phenological variables were recorded on 52 accessions representing different geographic regions. The highest degree of variability was observed for traits related to bud density and distribution, and to phenological variables associated with temperature requirements such as budbreak and harvest seasons, leaf fall, fruit development, and seed stratification period. Principal component analysis (PCA) integrated groups of phenotypes based mainly on growth habit, shoot diameter, bud and leaf size, as well as resistance to powdery mildew, rust, and frost. PCA provides support for the development of objectives and breeding strategies in the search for germplasm and cultivars for nontraditional peach growing regions.
W.C. Lin and P.A. Jolliffe
The importance of light intensity and spectral quality on fruit color and shelf life of long English cucumber (Cucumis sativus L.) was studied in four greenhouse experiments. The intensity of cucumber greenness was measured nondestructively by video imaging, and shelf life was measured by visual observation of incipient yellowing. In the summer, filters were used to cover individual fruit to reduce light intensity reaching the fruit surface. The lower the light intensity incident on a cucumber, the shorter its shelf life. The average shelf life was 8, 5, or 1 days for cucumbers receiving 100%, 66%, or 31% of natural daylight, respectively. The fruit that were covered with a filter transmitting red (R) light were greener (low grey level via video imaging) than those with a far-red (FR) filter. In the fall, fruit receiving spectral R lighting from fluorescence tubes were greener and had a longer shelf life than those receiving FR lighting from incandescent bulbs. In the winter, high-pressure sodium (HPS) lighting was necessary to supplement natural daylight for crop growth and production. Under HPS, R and FR lighting produced the same fruit greenness and shelf life. In the spring, R-lighted fruit had longer shelf life than FR-lighted ones, although fruit color at harvest was similar. In these four experiments, postharvest shelf life of long English cucumber was generally related to fruit greenness upon harvest. The data suggest the importance of an open canopy in improving fruit greenness and shelf life of greenhouse-grown cucumbers.