Morphological study of the formation and development of basal shoots in roses.

Basal shoots are the vigorous shoots at the base of the plant. In roses, basal shoots determine the potential flower production of the plant. Although many attempts have been made to promote the formation of basal shoots for commercial production, little attention has been paid to the origin and development of these shoots. The present study addresses this by following the development of a rose plant, raised from a cutting. Basal shoots only originated from basal axillary buds and not from adventitious buds. The first basal shoot of a plant emerged from one of the two most basal axillary buds of the primary shoot. The second basal shoot also emerged from an axillary bud of the primary shoot or, sometimes, from an axillary bud of the first basal shoot. If a third basal shoot occurred, it originated from an axillary bud of a basal shoot. The buds, which became the first and second basal shoot, were already present as secondary buds in the axils of the scales of the axillary bud when used for propagation. During the development of this primary bud into the primary shoot the secondary buds continued to initiate new leaf primordia, but did not sprout until the growth of the primary shoot slowed down. Removal of these two secondary axillary buds in the primary bud resulted in less basal shoots per plant and the basal shoots developed from buds number 3, 4 or 7