The 2012 ASHS Annual Conference

Cultivars of ornamental annual species are commonly evaluated for field performance prior to commercial introduction.  Evaluation for postharvest performance is less common and there is very little information relating these two characteristics.  With this as our objective, seventeen cultivars of gomphrena were grown to flowering in 10-cm pots and evaluated in a simulated interior postharvest environment (21 °C with fluorescent lighting on 16 hrs per day) for 30 days.  Plants were assigned a performance rating every 10 days based on lower leaf yellowing and flower senescence.  After 20 days, all plants had good performance, but after 30 days, those cultivars with mediocre or poor performance exhibited yellowing lower leaves and senescent flowers.  Additional plants were field planted in beds and evaluated during the growing season from May to September in Texas.  Plants in the field were fertilized, weeded and watered as needed.  Monthly, plants were rated for landscape performance and flowering.  During mid-summer, all cultivars were performing well.  By the end of the season, mediocre and poor performers exhibited decreased flowering and unhealthy foliage.  In general, postharvest and field performance was similar.  Eight cultivars exhibited good postharvest and field performance both.  ‘Buddy Rose’, ‘Buddy White’, and ‘Gnome White’ exhibited poor postharvest and field performance both.  ‘All Around Purple’, ‘Audray Bicolor Rose’, and ‘Las Vegas White’ exhibited mediocre postharvest and field performance both.  ‘Gnome Purple’ exhibited mediocre postharvest performance and poor field performance.  The exceptions were ‘Buddy Purple’ and ‘Las Vegas Pink’ which exhibited good postharvest performance, but performed poorly in the field.  At the marketable stage, another set of plants were sealed in 55-gallon treatment chambers and exposed to 0 or 5 ppm ethylene for 24 hours in the dark.  Plants were evaluated for symptoms of ethylene damage including flower wilting and abscission and leaf senescence.  After 24 hours of exposure to ethylene none of the cultivars showed any symptoms of ethylene damage, suggesting that Gomphrena are insensitive or have very low sensitivity to ethylene.