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- Author or Editor: JoAnn Robbins x
Fruit weight and morphological characteristics of `Meeker' red raspberry (Rubus idaeus L.) fruit, including drupelets (height, diameter, number), receptacle cavities (depth, diameter), and pits (individual weight) were measured five times in 1988. Fruit strength, as measured by compression, was recorded. The relationship of fro-it weight to fruit strength had linear and quadratic components. Fruit weight was correlated with fruit strength, drupelet height and number, receptacle cavity depth and diameter, and individual pit weight. Besides fruit weight, fruit strength was correlated with drupelet diameter and number, receptacle cavity depth, and individual pit weight. Drupelet number, receptacle cavity depth, and individual pit weight provided the largest component contribution to fruit strength, as determined by path analysis.
Weight and morphological characteristics of red raspberry (Rubus idaeus L.) fruit, including drupelets (height, diameter, number), receptacle cavities (depth, diameter), and pits (individual weight), were measured on 78 seedlings from the cross `Chief' × `Chilliwack'. Fruit strength, as measured by compression, correlated with fruit weight, drupelet number, receptacle cavity depth, and individual pit weight. Fruit weight was positively correlated with all morphological characteristics. Individual pit weight, drupelet height, and drupelet number provided the largest component contributions to fruit strength as measured by path analysis.
The effects of delayed precooling on fresh red raspberry fruit during storage was determined. Precooling was delayed for 0.5 to 12 hours, followed by cold storage for 8 days, with subsequent storage at 20C for 24 hours. Weight loss was greater with increasing delays of precooling. Fruit that lost more weight during the delay period lost less during the subsequent S-day storage at 0C. The exception was fruit held for 12 hours before precooling. Weight loss during the final 24 hours at 20C showed no pattern. Cumulative weight loss at the end of the storage treatments was similar regardless of delay of precooling. Fruit strength was reduced by any delay of precooling. The effect of delayed precooling on color was not consistent in the 2 years using different cultivars. The results indicate that fruit should be precooled as quickly as possible after harvest for long-distance fresh marketing.
Morphological characteristics of whole red raspberry fruit (weight, density), drupelets (height, diameter, number), receptacle cavities (depth, diameter), and pits (individual weight) were measured three times in 1983 on five cultivars of red raspberry (Rubus idaeus L.) and three times in 1984 on 10 cultivars. Fruit strength, measured by compression and cohesion, was also recorded. Across all genotypes, compression and cohesion measurements were highly correlated with fruit weight, drupelet height and number, receptacle cavity depth, and individual pit weight. Drupelet height, drupelet number, receptacle cavity depth and width, and individual pit weight provided the largest component contribution to both cohesive strength and compression strength by path analysis.
Fruit strength in red raspberry was measured using a cohesion method that determines the force required to pull a fruit apart. This method was compared to the compression method, which measures the force required to flatten the fruit. Fruit maturity significantly affected accuracy; the cohesion method was most variable for ripe fruit. A relatively low coefficient of variation across all maturity types indicates that the compression method is preferable for between-maturity comparisons, using a log transformation to produce variance homogeneity. With both methods, red ripe-stage raspberries showed significant differences between clones; the coefficients of variation for each method were similar within each clone. Variances were homogeneous using either method. The cohesion method gave relatively low absolute measurements that were highly correlated with those obtained using the compression method. Therefore, either method should be acceptable for measurements made within one maturity type.
Strawberry (Fragaria × ananassa Duch.) seedlings were planted in a greenhouse at 3- to 4-week intervals and simultaneously inoculated at ages 80, 101, 129, or 157 days with either of two naturally occurring virus sources each of which contained a mottle, mild yellow edge, and crinkle virus complex. Inoculation by aphids with either virus source reduced vigor, petiole length, leaflet width, stolons per plant, and vegetative dry weight of plants in the greenhouse. The tendency of virus inoculation to reduce vigor and petiole length was inversely proportional to increasing seedling age. In the field, inoculated seedlings were also less vigorous than control seedlings. Virus source effects and seedling age interactions with virus source were not significant. Selection for virus tolerance, based on greenhouse vigor, petiole length or leaflet width measurements, increased the frequency of seedlings subsequently classified as virus-tolerant in the field in both 80- and 101-day-old seedlings. Selection based on greenhouse vigor or petiole length increased the frequency in 129-day-old seedlings. No greenhouse selection method evaluated was effective in 157-day-old seedlings.
‘Meeker’ red raspberry (Rubus idaeus L.) fruit harvested at three maturity stages [inception (IN), red ripe (RR), and processing ripe (PR)] on four harvest dates at weekly intervals were held 0, 3, 6, and 9 days at 0°C and 90-95% RH. Fruit retention strength, firmness, and titratable acidity decreased with increasing maturity, while berry weight, total anthocyanin concentration, pH, and postharvest rot incidence increased. Fruit were darker visually with increasing maturity when compared to color standards. Soluble solids differences among stages of maturity were not consistent for all harvest dates. During storage, fruit at all stages of maturity increased in pH, total anthocyanin concentration, and postharvest rot incidence, but decreased in titratable acidity and darkened visually. The rate of increase in anthocyanin concentration and visual darkening was greater for IN and RR fruit than PR fruit. Total anthocyanin concentration accounted for 85% of the variation in visual darkness. Changes in red hues during storage, and differences in red hues among stages of maturity, were not consistent for all harvests and were not related to total anthocyanin concentration. Firmness increased during storage for the first harvest date, but decreased for the remaining three harvests. Berry weight, firmness, and titratable acidity decreased for all stages of maturity with later harvest dates, while postharvest rot incidence increased. This decrease in berry weight was greater for RR fruit than IN or PR fruit. Harvest date affected pH and rate of weight loss of all maturity stages and fruit retention strength of IN and RR fruit, but not PR fruit. Total anthocyanin concentration increased with later harvest dates of PR fruit, but did not change in IN or RR fruit. Soluble solids decreased linearly with harvest date in IN and PR fruit, but changed nonlinearly in RR fruit.
Fruits of red raspberry (Rubus idaeus L.) cultivars were harvested at the red-ripe stage and stored at 0C for up to 36 days. Firmness and titratable acidity generally decreased during storage, while anthocyanin and pH generally increased. Cultivars differed in rates and direction of change in firmness and pH during storage, and means differed at successive storage periods. Cultivars generally maintained their at-harvest ranking through storage in all characters. Cultivars differed in respiration rate. Respiration rate was positively correlated with ethylene evolution, rot, weight loss, and change in soluble solids concentration after 36 days in storage, and negatively correlated with change in firmness after all storage periods.
Strawberry (Fragaria × ananassa Duch.) seedlings of a 4-parent diallel and runner plants of their parent cultivars were inoculated with naturally occurring complexes of mottle, mild-yellow edge, and crinkle viruses by infesting plants with viruliferous aphids. The parent cultivars, chosen to represent a range in tolerance to complexes of these viruses, were ‘Hood’, ‘Olympus’, ‘Rainier’, and ‘Totem’ (listed in order of increasing tolerance). Virus inoculation reduced seedling plant vigor, petiole length, leaflet width, leaf dry weight, and parent plant vigor, but increased the numbers of leaves per plant of both seedlings and parents in the greenhouse. After growing in the field, virus-tolerance ratings of inoculated seedlings were lower than ratings of control seedlings. General combining ability constants for inoculated seedlings were similar, in rank and separation, to those reported by previous investigators. Field virus-tolerance ratings were lower than controls for inoculated plants of only one parent (‘Olympus’) and were higher than controls at the final evaluation for inoculated plants of a 2nd parent (‘Totem’). Genotypic differences among seedlings and parents confounded the effects of virus inoculation in both the greenhouse and the field. Petiole length in the greenhouse was correlated most consistently with subsequent field virus-tolerance ratings. The mean virus-tolerance ratings of inoculated seedlings, selected on the basis of petiole length, was higher than the rating of all inoculated seedlings and did not differ from the rating of control seedlings.