2014 ASHS Annual Conference

Rose (Rosa spp.) is an important ornamental crop which is commercially utilized for garden plants, cut flower, and food/medicinal/aroma industrial use. Heat stress is a major abiotic stress in Texas and in the world. It affects the rose appearance by causing increased flower abscission and leaf damage, and decreased flower size. This can reduce its market value. To increase the heat tolerance in rose cultivars, breeding lines derived from wild rose species Rosa wichurana were utilized as donor source in trait introgression. In this project, 10 hybrid populations were created by crossing both heat tolerant and sensitive diploid parents including TAMU breeding lines (M4-4, J06-20-14-3, DD, Rosa wichurana‘Bayse’s Thornless’) and commercial cultivars (‘Red Fairy’, ‘Sweet Chariot’, ‘Vineyard Song’, ‘Old Blush’, ‘Little Chief’, ‘Ducher’). All the parents and the progenies were propagated and grown in pots under greenhouse conditions. Before giving them a heat shock treatment (44 ℃ for 30 minutes) the roses will be pruned uniformly to obtain synchronized flowering for the heat treatment.  After the heat shock the plants along with untreated controls will be assessed for flower abscission, leaf necrosis, flower size and petal number. This growth chamber heat tolerance data will be compared to field ratings of flower intensity and plant growth of the same rose genotypes in the field over cool and warm temperature seasons.