ISHS Acta Horticulturae 544: IV International Walnut Symposium
ASSESSMENT OF LOSSES DUE TO DROP OF FLOWERS AND YOUNG, |
| Authors: | N. Neves, A. Gonçalves, C. Carvalho, C. Alves, J.M.S. Martins |
| Keywords: | walnut blight, flower drop, fruit drop, loss assessment |
| Abstract:
Drop of flowers and young fruits was observed during two years, in a plot planted with ‘Lara’ where copper treatments were being evaluated. A correlation of flower and fruit drop with external necroses due to bacterial blight infections could not be found, a great proportion of fruits with early-formed necrotic spots reaching maturity. Highest propor-tions of dropped flowers and fruits were observed during bloom and immediately after pollination, irrespective of the treatment, reaching 40 to 60 % of the tagged flowers. Al-most all the lost flowers and fruitlets seemed healthy, but lesions would be difficult to ob-serve on them due to their small size. A similar study was made on a collection of 16 cultivars. A good correlation was found between the proportion of fallen fruits and the period of fruit development when drop occurs, indicating that the earlier the fruits drop, the sounder they are. The studied cultivars can be divided in two groups based on the relation of percentages of total fruit drop to percentages of drop before fruit set. The genealogy of these two groups does not explain their separation. | |
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