THE EFFECT OF PINCHING ON THE GROWTH AND DEVELOPMENT OF ROSA-CHINENSIS MINIMA (SIMS) VOSS CULTIVARS

In fifty-five dwarf rose cvs currently used for pot culture, the gener al effects of pinching on the duration of the cultivation cycle and th e plant habit were studied. Plants propagated by single-node softwood cuttings were pinched or left unpinched, and grown until anthesis. In the pinched category, the number of days to anthesis, the plant height and width, and the numbers of flower buds and of bottom-breaks were s ignificantly larger, whereas the number of laterals and the growth rat e were smaller than in the unpinched category. In both categories, ver y significant genotypical differences for these characters occurred. S ignificant correlations between corresponding characters in the two ca tegories indicate basically the same behaviour of cvs. Without pinchin g, none of the cultivars involved showed sufficient quality. Some alte rnatives for, or in addition to pinching are considered.