MEAN DAILY MAXIMUM TEMPERATURE FOR 8-14 DAYS BEFORE HARVEST AS A GOOD PREDICTOR OF CHANGE IN GARDEN ROSE FLOWER DRY WEIGHT
Heat stress is a major limiting factor for growing crops and can severely affect rose flower quality and post-harvest quality. Flower dry weight and the number of vegetative nodes to flowering of fourteen adapted garden roses were studied during 2010 and 2011. A simple linear model based on the mean daily maximum temperature for 8-14 days (2WkMax°C) before the flowers open grouped the 14 cultivars into two groups: cluster 1 with a predicted 4.3% and cluster 2 with a 6.5% decrease in average flower dry weight for a 1°C increase in 2WkMax°C. The average mean daily temperature recorded during the growth period for plants was 24.7°C, with the maximum and minimum daily average of 34.4 and 2.22°C. The number of vegetative nodes to the inflorescence was affected by the growing season but the change and magnitude were cultivar dependent. The number of nodes of some cultivars was not affected by the growing season and could be an indicator of heat tolerance. The change in number of nodes and predicted change in flower size appears to be separate traits and could aid breeders in selecting better adapted material.
Greyvenstein, O., Starman, T., Byrne, D.H., Pemberton, H.B. and Genhua Niu, (2015). MEAN DAILY MAXIMUM TEMPERATURE FOR 8-14 DAYS BEFORE HARVEST AS A GOOD PREDICTOR OF CHANGE IN GARDEN ROSE FLOWER DRY WEIGHT. Acta Hortic. 1064, 67-72
Rosa ×hybrida, heat stress, flower size, landscape