Mustaherukan kukankehitys ja marjanmuodostus

Authors

• J. E. Hårdh Helsingin yliopiston Puutarhatieteen laitos, Viik, Pihlajamäki
• Johanna Wallden Helsingin yliopiston Puutarhatieteen laitos, Viik, Pihlajamäki

DOI: https://doi.org/10.23986/afsci.71625

Abstract

Development of flower primordia in the areas north of the 60th latitude is scarcely known. The differentiation data on Lepaan musta (Lepaa black), Brödtorp, Wellington xxx and of Silvergieter (Silvergieters Zwarte) in Viik, close to Helsinki, are given (Tables 2 and 3). Table 4 gives the differentiation stages of Lepaan musta, Brödtorp, Wellington xxx and of Laxtons Tinker on four latitudes in Finland. It is clear that differentiation is delayed by the long day in the north (Table 5) and that a daylength of less than 13 hours favours the differentiation process. This was confirmed in tests with an artificial prolonging of the day (Table 6). The Finnish varieties Lepaan musta and Brödtorp seem to be more adapted to the long day conditions than Wellington xxx and Laxtons Tinker. Development of the primordia occurs during winter, despite the temperature remaining far below zero, until the fifth stage (9, 20), where overwintering occurs (Table 3). Flowering data are given in Table 7. In pollination tests in 1963 and 1964 it was shown that Lepaan musta belongs to the completely self-fertile varieties, Brödtorp to partially self-fertile ones (7, 8, 12). On Lepaan musta and Brödtorp the intrafloral self-pollination gave better berry formation than interfloral self-pollination. Of the pollinating varieties Wellington xxx was more vigorous than the domestic varieties Lepaan musta for Brödtorp and vice versa (Tables 8 and 9). »Running off» in the tests was stated to depend on a low number of seeds in the berries (Table 10). Close correlation existed between the size of berry and the number of seeds (Figures 2 and 3).