Vascular tissue and cell dynamics during bent neck formation sweet heart and intermediate roses

Abstract

Rose plants are ornamentals most selling in the world market. Bent neck Peduncle phenomenon (BPP) compromises their quality. The objective of this study was to explain the basis for the high prevalence of bent neck in sweet heart roses and old plants at the vascular tissue and cell level. It was hypothesized is that bent neck formation is1) caused by large flower bud weight that becomes too heavy for the stem to withstand, 2) prevalent in rose cultivars with large bud weight to neck diameter ratio, and 3) due to non-uniform cell division and expansion around the neck region of the flower stem. Treatments considered were cultivar, age and cultivar group (intermediates and sweet hearts). Data was collected on stem length, neck diameter, bud weight and Internode number. Key results were that BPP occurred in all the cultivar groups. Neck diameter in the bent neck was found to be thinner than of the normal neck. Stem length in bent necks were shorter than in normal necks but not much different in comparison of individual plants other than Akito with the smallest length while the cultivar groups had similar stem lengths. Neck diameter of the bent was smaller than in the normal neck and much smaller in the sweetheart relative to intermediate cultivars.