Effect of preharvest growing temperatures on the development of cut roses

Abstract

Two Rosa hybrida L. cultivars, Meitakilor and Meired, were grown in two different greenhouses; one was kept in cool conditions and the other one in warm conditions. Flower stems of both cultivars in both greenhouses were cropped at two well defined stages corresponding to different bud development states. Their vase life was observed in uniform conditions. The different temperature regimes during the growth determined different harvest dates and different morphological traits (such as flower bud length and number of petals) but also different opening abilities when cut flowers were held in water. These opening characteristics were also functions of the cultivar and bud stage at harvest. Although the flower stems cropped at the cracked bud stage opened with more facility and were slower to reach a fully opened stage than the ones cropped at a tighter stage, the latter crop stage seems more or less adapted to the warmest growth conditions generated here (at least for one cultivar). The less developed flower buds did not open well following cooler growing conditions. The results presented are largely in agreement with growers practices in different areas and under various cultural conditions.