The 2011 ASHS Annual Conference

Roses are popular garden plants in the world.  Due to intense competition for fresh water among agriculture, industry, and domestic water users, alternative water sources such as municipal reclaimed water are being used for irrigating landscapes in some regions.  The responses of roses to irrigation water with elevated salts are unknown. Two experiments were conducted to evaluate the relative salt tolerance of 13 self-rooted rose cultivars by irrigating the plants with nutrient solutions at an electrical conductivity (EC) of 1.34 dS/m (control), or nutrient saline solutions at EC of 3.10, 4.44, or 6.39 dS/m.  In Expt. 1, ‘Belinda’s Dream’, ‘Caldwell Pink’, ‘Carefree Beauty’, ‘Folksinger’, ‘Quietness’, and ‘Winter Sunset’ plants were grown in a greenhouse from 13 Aug. to 21 Oct. (10 weeks).  Plants were transplanted from 1.8-L containers to 2.6-L containers on 3 Sept. and were pruned to same height (about 7 cm).  Shoot dry weight of all cultivars decreased linearly as EC increased, except for ‘Folksinger’, which had powdery mildew in all treatments.  ‘Winter Sunset’ was most sensitive among these cultivars to salt stress, followed by ‘Carefree Beauty’ and ‘Folksinger’, with severe leaf injury or death at EC 3.10 or higher.  No visual damage was observed in ‘Belinda’s Dream’ and ‘Caldwell Pink’ regardless of the salinity level.  In Expt. 2, ‘Bayse’s Blueberry’, ‘Iceberg’, ‘Little Buckaroo’, ‘The Fairy’, ‘Marie Pavie’, ‘Rise N Shine’, and ‘Sea Foam’ plants were grown in 2.6-L containers in the greenhouse from 29 Sept. to 16 Nov. (7 weeks) and irrigated with the same nutrient or nutrient saline solutions.  Salinity treatment did not affect shoot dry weight of ‘Bayse’s Blueberry’, ‘Little Buckaroo’, ‘Sea Foam’, and ‘Rise N Shine’.  Shoot dry weight of ‘Iceberg’, ‘The Fairy’, and ‘Marie Pavie’ decreased as EC of irrigation water increased.  No visual damage was observed in ‘Little Buckaroo’, ‘Sea Foam’, and ‘Rise N Shine’.  Slight leaf tip burns were found in ‘Iceberg’, ‘Marie Pavie’, ‘Bayse’s Blueberry’, and ‘The Fairy’ at EC 6.39. Generally, these symptoms were less severe than those observed in Expt. 1, probably due partially to shorter treatment period.  Further experiments will be conducted to confirm the results and compare all these cultivar at the same time.