Incidence and severity of the floral bud disorder “budjump”, on nashi (Pyrus serotina) grown in the Waikato region of New Zealand

Abstract

The incidence and severity of bud loss as a result of the floral bud disorders collectively called “budjump”, were investigated from 1986 to 1991 throughout the Waikato region of New Zealand. Large variation was found in levels of bud loss from year to year. Most bud loss was found in the cultivar ‘Hosui’, with high levels of bud loss significantly reducing fruit production in some years. In the cultivars ‘Kosui’, ‘Shinsui’, ‘Nijisseiki’, and ‘Shinseiki’ bud loss was much less severe. On ‘Hosui’ most bud loss was found on young trees, and on young wood on older trees. Least bud loss was found at branch tips and on spur buds on older wood. High levels of bud loss were also associated with reduced flower numbers in remaining flower clusters. The type of rootstock and training system used had no effect on the incidence of budjump.

Keywords:

• nashi
• Pyrus serotina
• budjump
• floral bud disorders
• flowering
• fruit production
• Hosui