Adaptability of cut rose (Rosa hybrida L.) varieties for shade and high temperature conditions in tropical greenhouses

Rose (Rosa hybrida L.) is one of the most popular cut flower species grown under protected culture in the world. However, in Sri Lanka, the commercial cultivation is limited to upcountry region due to low temperature. Even though many rose varieties are grown in relatively warm regions, their growth rates and productivity vary due to the lack of adaptability to temperature stress. Therefore, this research was conducted to identify adaptable varieties for moderately high temperature and partial shade in a replicated greenhouse research in Mid Country Wet Zone (MCWZ) and Intermediate Zone (MCIZ) of Sri Lanka. Rose varieties Black Magic and White Success were identified to be more adoptable to warm and humid greenhouse conditions in the MCWZ and MCIZ during Yala season with respect to plant growth and flower yield. However, White Success was comparatively lower in marketable flower percentage and flower quality, compared to Black Magic. Cut flower varieties, Grand Gala and Peach Pope showed longer shelf-life compared to Black Magic and White Success. The types of shades, Aluminet (25 %) and black shade net (50 %), reduced the mean daytime temperature difference to 2.1±0.13 between greenhouse air and outside air. The rose varieties Black Magic, Grand Gala and White Success could successfully be grown to obtain a good quality flower yield under the shade of Aluminet (25 % shade) in the greenhouse. The recognized the adaptability of the selected rose varieties to tropical greenhouse conditions, and the potential use of Aluminet (25 % shade) as a temperature control measure in rose-producing greenhouses.