Single-bud Cuttings Research Articles

カルシウム•シアナミド及びシアナミドがブドウ‘巨峰’の芽の休眠打破に及ぼす効果

Bud breaking effects of a leaching solution containing 20% lime nitrogen (55% CaCN2) and cyanamide (H2CN2) applied to the surface of dormant buds of glasshouse grown vines and single-bud cuttings of ‘Kyoho’ grape were examined.Treatment of intact vines with CaCN2 in December, January and February advanced bud break in the following spring by 16, 9, and 5 days, respectively. Treatment during the period of deep dormancy was most effective, in agreement with previous results. The effect of 3% H2CN2 given at the corresponding times was very similar to that of CaCN2, with bud break being advanced by 15, 7 and 4 days, respectively.Treatment of the single-bud cuttings bedded in December with CaCN2 and 0.5 or 1% H2CN2 during the same month advanced the bud break by 2 to 4 days. The bud breaking effect on the cuttings was much smaller than on the intact vines. Furthermore, at concentrations of H2CN2 above 2%, buds of the cuttings died due to chemical injury. In cuttings, the effective concentration of H2CN2 was one-third to one-sixth of that in intact vines. This might be the result of shallower dormancy due to wound effects in the cuttings. In late February, when dormancy had been broken, chemical injury to the cuttings occurred even when treated with CaCN2 and 1% H2CN2.These results indicate that H2CN2 has the same effect as CaCN2 on bud break of ‘Kyoho’ grape, which suggests that the bud breaking effect of lime nitrogen is mainly due to the active form of the cyanide ion (CN-), H2NCN being produced by partial hydrolysis of CaCN2.

A Study of Two Black Currant Chimaeras

Detailed studies of two black currant varieties, Daniels’ September and Laleham Beauty, failed to show any morphological differences between them, except slight differences in time of flowering and bush vigour. Both varieties are infected with a virus complex causing characteristic leaf mosaic and both behave as periclinal chimaeras, or bud sports, producing distinct early- and late-ripening fruit from morphologically different inflorescences. Propagation by single-bud cuttings and other methods failed to fix either type but showed the late type to be less variable than the early type.

Propagation of Black Currants from Single-Bud Cuttings

SummaryBlack currants are readily propagated from single-bud hardwood cuttings approximately i inch long, with the bud at the top and planted vertically. The best part of the shoot from which to take such cuttings is the lower- mid portion (buds 15-22).Optimum rooting is obtained from cuttings planted in January, February and March after dormancy has broken in the field, but by using 24-hour day-length successful rooting can be extended from October to March. The emergence of flowers in March-planted cuttings slightly reduces rooting.Thirteen commercial varieties have been propagated successfully by this method.Suitable softwood and semi- hardwood cuttings are available when the current season's shoots are 12 nodes or more in length, i.e. normally in late April. When these are planted in a propagation frame with soil heating, good rooting is obtained from April to June provided the subtending leaf is retained during the rooting period.Twenty-four-hour day-length increases the rooting of cuttings planted i...