Apoyos Gubernamentales y No Gubernamentales

In the fi rst planting year (year 1) the ‘handle’ or main stem is cut and removed several weeks after planting to reduce disease spreading from the stem onto the new soft stems. If the grower receives clean plants and applies a fungicide during the season, this practice may be unnecessary. No other pruning is suggested during the fi rst year.

Plants that are subjected to good weed control and frequent irrigation during the fi rst year can, in the second year, produce stems and many laterals that are 1–1.2 m (3–4 ft). These stems and laterals can be detached from the soil at the tip and single canes are tied to the trellis wire (support system) and

128 R.C. Funt

then headed in a manner to extend 20 cm (8 in) beyond the wire for easy picking (Fig. 10.3g). In some cases, laterals are thinned to maintain some space for air movement or canes that are too small in diameter are removed.

Moderate yields (fi rst baby crop) can be harvested. If there are few stems or laterals to reach the wire, it may be best to cut most of the growth and leave an untied stem 30 cm (12 in) long. This will allow sunlight into the interior part of the row for the primocane to grow.

Before harvest in the second or subsequent years, primocanes (new canes) are headed at 60 cm (24 in) for stocky and self-supporting canes (no support system) (Slate et al., 1949). This is referred to as raspberries trained to the solid row system (Fig. 10.3b). Canes can also be headed at 90 cm (36 in) for a T-trellis system. In either case, allow the canes to grow 10 cm (4 in) above the recommended height and remove this part from the top, leaving the cane 60 or 90 cm (24 or 36 in) tall (Plate 10.2 and Fig. 10.5). The heading (tipping) can be done by hand pinching with gloved hands, with a sharp knife, or with pruning shears. Because all plants do not reach the same height at the same time, the pruning may need to be done every few days. A fungicide spray, within 24 h after pruning, on this soft wood will reduce diseases entering the cut. If the plants are not pruned and grow above a height of 1.2 m (4 ft), the laterals will be short and stems will be weak. No additional pruning of canes or laterals should be done until the canes are dormant or after the coldest temperatures of the winter have been reached.

Generally, the heading at 90 cm (36 in) reduces stooping to pick the berries from laterals that grow between 90 cm and 1.2 m (36 in and 48 in).

Therefore, people can stand erect and reduce spillage from either their hands

Newly headed canes Lateral growth 2 months after heading 2˝–3˝

20˝–24˝

Fig. 10.5. Heading (cutting back from tip) of black or purple raspberry in summer (left); lateral growth after heading (right). (Courtesy of The Ohio State University.)

Pruning and Training 129

or container. It appears that these taller canes may be better for mechanical harvest. They are also easier to prune. However, primocanes headed at 60 cm (24 in) can be self-supporting, requiring no trellis, and therefore, reduce establishment costs.

After the fl oricanes have fruited, the spent (old) canes should be removed by cutting the stem near the soil. In warm climates (zones 7 to 8), spent canes can be removed in early to late autumn without subjecting the canes to possible winter injury or to delayed acclimation. In cold climates (zones 5 to 6), canes should be removed in late winter or early spring.

Prior to the removal of the spent black raspberry canes, laterals, which can be 90 cm (3 ft) or longer are cut back to 20–35 cm (8–14 in) in length (Fig. 10.6), leaving eight to 12 buds (Slate et al., 1949). Cutting back the laterals prior to the removal of spent canes makes it easier to remove spent canes to the aisle (Plate 10.3). Most of the fruit buds are on the plant’s laterals; laterals that are pencil sized in diameter (0.6 cm/0.25 in) can be pruned to a longer length than those that are smaller in diameter. Fruit size will be larger on thick laterals (Plate 10.3). Laterals smaller in diameter than a pencil should be pruned at 15–20 cm (6–8 in) to improve fruit size. The pruning should be completed after the severest cold weather has passed so as to be able to remove canes or laterals that have been damaged by low winter temperatures.

Floricanes (new canes) are thinned to four to six canes located in clusters of the original plant. Remove canes that are less than 1.2 cm (½ in) in diameter at the base of the plant. A large number of canes per unit of land (14,000 to 16,000 per hectare (5500 to 6500 per acre)) are preferred

Fig. 10.6. Black and purple raspberry before (left) and after (right) dormant pruning.

(Courtesy of The Ohio State University.)

130 R.C. Funt

as compared to fewer canes and longer laterals. The plants remaining are oriented to both sides of the row, with each plant and lateral independent (no crossing over) of each other, so that the berries and canes are receiving good air movement and are easily harvested. With a V-shape from the top to bottom, sunlight can reach the soil and allow strong plants to grow for the next year. Flower bud initiation occurs in late autumn, followed by fl ower development in late spring. The newly developed spineless black raspberries may be similar in growth habit to red raspberries and could be managed in a similar way.

Purple raspberries

Purple raspberries are crosses between red and black raspberries which produce reddish to purple fruit. Many purple raspberries are pruned similarly to red raspberries and are not headed in the summer. Other cultivars of purple raspberries, such as ‘Brandywine’, will respond to summer heading like black raspberries. Heading should occur at 90 cm (3 ft) on these types. Generally, purple raspberry cultivars in the USA are vigorous and grow very tall. Leaving three to four fruiting canes per linear foot (30 cm) of row is acceptable. Both types will require some type of trellis. Primocane suppression can be used to control this vigor with good results (Pritts and Handley, 1989).