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Western trailing blackberries (e.g., `Boysen' and `Marion') are grown in Oregon. USDA-released semi-erect thornless blackberries (e.g., `Chester Thornless') and erect, thorny blackberries (e.g., `Cherokee') from Arkansas are grown across the United States from the mid-Atlantic coast region to Oregon. Flower bud development in several blackberry cultivars growing at three sites (Arkansas, Oregon, and West Virginia) was studied. In buds of `Boysen' and `Marion' blackberries from Oregon, sepal primordia were first observed in September and November, respectively. Further floral bud development continued into January. Sepal development in `Cherokee' buds occurred in November in Oregon and in December in Arkansas. At all subsequent sampling dates, the development was more advanced in Oregon than in Arkansas. Buds of `Chester Thornless' blackberry from all three sites remained undifferentiated until spring. Preliminary findings indicated that the time of flower bud initiation varied considerably among the cultivars examined. The results suggest that floral bud development in blackberry, once initiated, is continuous, but periods of low temperature can arrest bud development.
Biennial bearing has long been thought to occur in cranberry (Vaccinium macrocarpon Ait). Researchers have shown that percent return bloom on fruiting uprights can range from 12% to 65% depending on year, bed vigor and cultivar. Resource limitation and/or hormonal factors in a fruiting upright may be related to flower bud initiation and, thus, percent return bloom the following year. This research was undertaken to determine the extent of biennial bearing by cranberry cultivar and growing region. Seven cultivars were studied; three found in all states (MA, NJ, WI, OR), two common to MA and NJ, and two different cultivars in WI and OR representing cultivars commercially grown in these areas. In the fall or winter of 1989/1990 six 2-m transects were randomly selected within a cranberry bed for each cultivar. Along the transect, 60 uprights that fruited in 1989 were tagged. In the summer of 1990, fifty of the uprights will be sampled to determine percent return bloom and percent set.
Biennial bearing has long been thought to occur in cranberry (Vaccinium macrocarpon Ait). Researchers have shown that percent return bloom on fruiting uprights can range from 12% to 65% depending on year, bed vigor and cultivar. Resource limitation and/or hormonal factors in a fruiting upright may be related to flower bud initiation and, thus, percent return bloom the following year. This research was undertaken to determine the extent of biennial bearing by cranberry cultivar and growing region. Seven cultivars were studied; three found in all states (MA, NJ, WI, OR), two common to MA and NJ, and two different cultivars in WI and OR representing cultivars commercially grown in these areas. In the fall or winter of 1989/1990 six 2-m transects were randomly selected within a cranberry bed for each cultivar. Along the transect, 60 uprights that fruited in 1989 were tagged. In the summer of 1990, fifty of the uprights will be sampled to determine percent return bloom and percent set.
Cranberries (Vaccinium macrocarpon Ait.) require low rates of N fertilizer compared to many horticultural and agronomic crops. Excess N promotes vegetative growth at the expense of yield. Growers desire information about N fertilization to achieve optimum yields without overgrowth, Little information has been published about N rate and timing influence on cranberries in south coastal Oregon. An N rate and timing field experiment with Crowley and Stevens cultivars was established to answer grower questions. N was applied at 0, 18, 36 and 54 kg/ha in various combinations at popcorn (white bud), hook, fruitset, early bud, and late bud. Yield, yield components, (fruit set, number of flowering and total uprights, berry size, flowers per upright and the proportion of uprights that flower), vegetative growth and anthocyanin content were measured. After 2 years of treatments, N rate or timing had little influence on yield or yield components in the previously heavily fertilized Crowley bed. In the previously lightly fertilized Stevens bed, N rate increased yield, vine growth, and the number of flowering uprights, N timing also influenced the number of flowering uprights. The total number of uprights was influenced by the interaction of N rate and timing.
Biennial bearing of uprights has been documented for cranberry (Vaccinium macrocarpon Ait.). Percent return bloom (%RB) may vary from 14% to 74% depending on cultivar and growing region. Floral initiation for the following season in cranberry takes place during the same time period as flowering and fruit set for the current season. This research was undertaken to document the effect of fruiting or not fruiting in the previous year on %RB and %RF (return fruit) in two cultivars (Stevens and Ben Lear) and five growing regions (MA, NJ, WI, OR, WA). Previous year fruiting caused a reduction in %RB compared to non-fruiting in the previous year. The effect on %RF was even greater. For `Ben Lear', uprights that fruited in 1990 had 31%RB and 22%RF while those that did not fruit in 1990 had 67%RB and 54%RF. Both %RB and %RF in 1991 were about 49% lower for `Stevens' which fruited in 1990 than those that did not fruit in 1990. It is still not clear whether biennial bearing in cranberry uprights is a function of hormonal interaction and regulation or of resource limitation or both.