Evaluation of Marigold Cultivars as Bedding Plants in Central Florida

Richard O. Kelly 1 and Brent K. Harbaugh 2

ADDITIONAL INDEX WORDS. african marigold, french marigold, Tagetes

erecta, Tagetes patula, variety trial

SUMMARY.

Annual bedding plants comprised 50% of the $4.6 billion wholesale value of United States floricultural crops in 2000. Florida is one of the top wholesale producers of bedding plants in this industry, and in 2000 was number one in the production of potted marigolds. Evaluation of marigold cultivars is vital for continued growth of the industry. We evaluated 84 cultivars of african marigold (Tagetes erecta) and french marigold (T. patula) in replicated class tests at the University of Florida’s Gulf Coast Research and Education Center at Bradenton, Fla. (lat. 274' N, long. 825' W; AHS Heat Zone 10; USDA Cold Hardiness Zone 9b) in Fall 1999. In this report, we provide objective plant measurements of vegetative and floral characteristics as well as six weekly subjective ratings. Subjective ratings were on a 1 to 7 scale with the highest rating of 7 for excellent. In general, cultivars with vegetative and floral ratings ≥5 were considered outstanding, 4 to 4.9 as good performers, and ≤3.9 as fair to poor. These ratings permit readers to evaluate foliage and floral characteristics at different times during the season, and to evaluate performance over time. Cultivars were grouped into classes based on species, plant height, flower type, and flower color. Outstanding cultivars (those cultivars with an overall rating ≥5) and their class were: ‘Inca Gold’ and ‘Royal Gold’ [african marigold (African)—gold class]; ‘Mesa Orange’ and ‘Royal Orange’ (African—orange class); ‘Inca Yellow’, ‘Mesa Yellow’, and ‘Perfection Yellow’ (African—yellow class); ‘Disco Granada’ [french marigold (French) dwarf—single gold/red class], ‘Disco Flame’ (French dwarf—single red/gold class); ‘Golden Boy’ and ‘Hero Gold’ (French dwarf—double gold class); ‘Bonanza Orange’, ‘Orange Boy’, ‘Girl Orange’, ‘Jacket Orange’ (French dwarf—double orange class); ‘YellowBoy’, ‘Girl Primrose’, and ‘Jacket Yellow’ (French dwarf—double yellowclass); ‘Harmony Boy’ (French dwarf— double orange/red class); ‘Hero Flame’(French dwarf double red/orange class); ‘Bonanza Flame Improved’(French dwarf—double red/yellow class); ‘Legend Gold’ (French double—gold class); ‘Legend Orange Improved’ (French—double orange class); ‘Spry Boy’ (French double—yellow/red class); ‘Durango Bee’, ‘Durango Red’, and ‘Hyper Red/Yellow’ (French—double red/yellow class). We believe these cultivars would perform well in the southern U.S. or areas of the world with similar heat and cold hardiness zones.

The United States wholesale value of floricultural crops was $4.6 billion in 2000, estimated from growers with sales ≥$10,000. (U.S. Department of Agriculture, 2001). Bedding and garden plants comprised 50% of the floriculture value at $2.12 billion. Florida ($107.4 million) ranked fifth behind California, Michigan, Texas and Ohio, which together generate 42% of the bedding/garden plant wholesale value. Hybrid marigolds were first introduced in 1939 by David Burpee (Burpee Seeds and Plants, 1999), and are now ranked fourth and eleventh in the United States for wholesale value in flat and pot culture, respectively (U.S. Department of Agriculture, 2001). Florida was number one (growers with sales ≥$100, 000) in the United States for the number of potted marigolds produced, and their wholesale value was $1.2 million in 1999–2000 (United States Department of Agriculture, 2001).

The bedding plant industry by its nature requires timely evaluation of cultivars for a competitive market. Many of the bedding plant cultivar trials currently conducted in the United States are performed without replicated experimental units. While those trials provide valuable observational information, they require replication over years to gain the benefits from statistical analysis. Since seed companies are releasing new cultivars yearly, timely evaluations are critical to provide growers with non-biased performance evaluations to help them make decisions concerning cultivar selection. Standards have not been developed for marigolds and thus new cultivars are often compared with a random number of cultivars chosen from over 100 commercially available cultivars.

This study was done to evaluate marigold cultivar performance in a seasonal replicated trial to provide timely evaluations that may be used by growers, landscapers, consumers and seed companies as well as the scientific community. These trials also were to establish cultivars to be used as standards (best-of-class), thus reducing the number of cultivars needed in future trials to these established standards and new releases.

Materials and methods

Seeds of 29 cultivars of african marigolds and 55 cultivars of french marigolds were sown on 10 Aug. 1999 into a soil mix containing 1 peat : 1 vermiculite (by volume) amended with dolomite 6.7 kg·m –3 (11.3 lb/yard 3 ), superphosphate 3.3 kg·m –3 (5.6 lb/yard 3 ) and hydrated lime 1.7 kg·m –3 (2.8 lb/yard 3 ). Seeds were allowed to germinate at 22.2 to 23.9 °C (72 to 75 °F) in a growth room with a photosynthetic photon flux of 30 μmol·m –2 ·s –1 for 12 h per day from cool-white fluorescent lamps. Immediately after germination, seedlings were transplanted into Todd‚ planter flats (model 128; Speedling Inc., Sun City, Fla.) [3.8 × 3.8 × 6.4-cm cells (1.5 × 1.5 × 2.5 inches)] and placed into a screen sided, fiberglass covered greenhouse. Seed-lings were fertilized weekly with a 20N–16.6P–8.7K water soluble fertilizer (20–20–20 Ca–Mg Excel; Scotts Co., Marysville, Ohio) solution containing nitrogen at 500 mg·L –1 (ppm). 

On 22 Sept., plugs were trans-planted into raised ground beds with six plants per plot spaced 30.5 cm (12 inches) apart in a staggered layout. Beds were 81.3 cm wide × 20.3 cm high (32 × 8 inches). Nutricote 14N–6.1P–11.6K fertilizer (14–14–14, 180-d slow release type; Florikan, Sarasota, Florida) was broadcast across the width of the bed at 3587.7 kg·ha –1 (3201 lb/acre) and incorporated to a depth of 7.6 to 10.2 cm (3 to 4 inches). Beds were fumigated 21 d before planting with a mixture of 66% methyl bromide and 33 % chloropicrin at 392 kg·ha –1 (350 lb/acre) and covered with white-on-black polyethylene film. Subsurface seepage irrigation water was supplied from lateral ditches spaced 12.8 m (42 ft) apart (Howe and Waters, 1997).

Integrated pest management was used to determine when pesticide applications were needed to control arthropod pests and plant pathogens. Temperature [University of Florida’s Gulf Coast Research and Education Center at Bradenton, Fla.; lat. 274' N, long. 825' W; AHS Heat Zone 10 (American Horticultural Society, 1999); USDA Cold Hardiness Zone 9b (U.S. National Arboretum, 1990)] at 61 cm (2 ft) above the ground during the remainder of the experiment ranged from a low of 6.2 °C (43 °F) to a high of 32.4 °C (90 °F) with a total rainfall of 6.9 cm (2.7 inches), (Florida Automated Weather Network, 2002).

On 9 to 10 Nov., plant height (from the stem base to the inflorescence tip), plant width at the widest point and flower diameter were recorded for three plants selected from the center and edge of each plot. Subjective ratings were made by the senior author on 27 Oct., 3, 10, 17, and 23 Nov., and 1 Dec. (evaluations were across all six plants resulting in one value per plot). A 1 to 7 scale was used with the highest rating a 7. Floral characteristics were rated within a scale as follows: 7 = flowers were numerous, uniformly distributed over all plants, flowers were free from pest symptoms; 4 = average floral display, may have some pest damage but not severe enough to cause flowers to be unacceptable; and 1 = unacceptable flower number or display, and/or pest damage severe resulting in unattractive flowers. Foliage ratings were as follows: 7 = all plants in a plot had full and uniform foliage, plants were free of pest symptoms and abnormalities or weaknesses such as lodging; 4 = average foliage density, minimal lodging, and/or some insect damage but foliage was still acceptable; 1 = foliage sparse, stem lodging, and/or unacceptable pest damage making plants undesirable. For a measure of performance over time, six weekly flower or foliage ratings were added and divided by six to provide an average flower or foliage rating. For a measure of overall performance (i.e., performance over time with combined floral and foliage performance), an overall rating was derived by taking the sum of the average floral and foliage ratings and dividing by two. In general, cultivars with vegetative and floral ratings ≥5 were considered outstanding, 4 to 4.9 as good performers, and ≤3.9 as fair to poor.

To provide meaningful performancecomparisons, cultivars were divided into classes based on species (african marigold or french marigold), height [dwarf ≤25.4 cm (10 inches); >25.4 cm], flower form (double if crested, anemone, or single), and flower color (gold, orange, red, yellow, and bicolored ). Bicolored classes were represented as x/y, with x = primary color and y = secondary or less predominant color.

Each class was analyzed as a separate experiment. A randomized complete block experimental design was used with three blocks containing six plants per plot. The experimental unit for objective data was the average measurement from three plants, and for subjective data, one rating value considering all six plants in the plot. All data were analyzed by analysis of variance (ANOVA) methods, and means of de-pendent variables significant at the 0.05 level of probability were separated using Duncan’s multiple range test (PROCANOVA, SAS Institute, Cary, N.C.).

Results and discussion

AFRICAN DWARF —ORANGE CLASS. ‘Pumpkin Crush’ plants were smallest at 20 cm (7.9 inches) high and 26 cm (10.2 inches) wide, but they had the largest flowers 7.3 (2.9 inches) (Table 1). Flower ratings were high (4.7 to 6.0) for ‘Pumpkin Crush’ and ‘Discovery Orange’ on 27 Oct. and 3 Nov. However, later ratings decreased rapidly indicating a narrow window of peak performance (Table 2).

AFRICAN —GOLD CLASS. Plant height ranged from 30 cm (11.8 inches) for ‘Mesa Gold’ to 50 cm (19.7 inches) for ‘Lady Gold’ and ‘Perfection Gold’. Plant width ranged from 34 cm (13.4 inches) for ‘Sunspot Gold’ to 53 cm (20.9 inches) for ‘Perfection Gold’. Flower diameters were from 6.5 cm (2.6 inches) for ‘Sunspot Gold’ to 9.3 cm (3.7 inches) for ‘Inca Gold’. ‘Lady Gold’ (3.8) and ‘Sunspot Gold’ (3.4) had below average foliage ratings, while ‘Sunspot Gold’ (3.1) and ‘Mesa Gold’ (3.1) had below average flower ratings.  Overall ratings were above average (4.6 to 5.0) for most members of this class except ‘Sunspot Gold’ (3.2) and ‘Lady Gold’ (4.2).

AFRICAN —ORANGE CLASS. Plant height ranged from 29 cm (11.4 inches) for ‘Antigua Orange’ and ‘Atlantis Orange’ to 47 cm (18.5 inches) for ‘Perfection Orange’. Plant width ranged from 31 cm (12.2 inches) for ‘Sunspot Orange’ to 50 cm (19.7 inches) for ‘Perfection Orange’. Flower diameters were from 5.9 cm (2.3 inches) for ‘Sunspot Orange’ to 9.2 cm (3.6 inches) for ‘Inca Orange’. ‘Mesa Orange’ (6.6) had the best average foliage rating, while ‘Atlantis Orange’ (3.3), ‘American Indian Orange’ (3.2) and ‘Sunspot Orange’ (2.7) had poor average foliage ratings. Good flower ratings on 27 Oct. and 3 Nov. were received for all cultivars except ‘Mesa Orange’ (2.3 to 3.0). Flower ratings were good for ‘Marvel Orange’ (4.7) and ‘Antigua Orange’ (4.8) to 10 Nov., and to 17 Nov. for ‘Royal Orange’ (5.3) and ‘Inca Orange’ (4.0). Average flower ratings were fair to low for this class (4.4 to 2.8).

AFRICAN —YELLOW CLASS. Plantheight ranged from 27 cm (10.6 inches) for ‘Antigua Yellow’ to 49 cm (19.3 inches) for ‘Perfection Yellow’. Plant width ranged from 33 cm (13 inches) for ‘Antigua Yellow’ to 47 cm (18.5 inches) for ‘Perfection Yellow’. Flower diameter ranged from 7.0 cm (2.8 inches) for ‘Antigua Yellow’ to 9.7cm (3.8 inches) for ‘Inca Yellow’. ‘Inca Yellow’ (5.3) and ‘Mesa Yellow’ (6.2) had the highest average foliage ratings, followed by ‘Perfection Yellow’ (5.4) and ‘American Indian Yellow’ (4.9). Early flower ratings, 27 Oct., were fair to low for ‘Mesa Yellow’ (3.0) and ‘Perfection Yellow’, but flower ratings were good through 10 Nov. for most cultivars, only falling lower after that date. However, ‘Perfection Yellow’ had extended good ratings to the end of the test.

FRENCH DWARF —SINGLE GOLD/RED CLASS. Plant and flower measurements for ‘Disco Granada’ and ‘Disco Marietta’ were not significantly different. ‘Disco Granada’ (5.6) had an average foliage rating significantly better than ‘Disco Marietta’ (4.1). Both cultivars had equally good flower ratings (5.0) from 10 Nov. to 17 Nov.

FRENCH DWARF —SINGLE RED/GOLD CLASS. Plant height ranged from 23 cm (9.1 inches) for ‘Disco Queen’ to 41 cm (5.5 inches) for ‘Red Marietta’. Plant width ranged from 39 cm (15.4 inches) for ‘Disco Queen’ to 53 cm (19.7 inches).481 July–September 2002 12(3) for ‘Red Marietta’. Flower diameters were from 4.8 cm (1.9 inches) for ‘Disco Queen’ to 5.3 cm (2.1 inches) for ‘Red Marietta’. ‘Disco Flame’ and ‘Red Marietta’ had significantly better average foliage (5.0 and 5.6, respectively) and combined (5.0 and 4.9, respectively) ratings. All members of the class had good flower ratings to 10 Nov. (5.0 to 6.0), and ‘Disco Queen’ (6.0) had a very good flower rating on 27 Oct. However, the flower rating averages for ‘Disco Flame’ (6.0) and "Red Marietta’ (5.7) were significantly better than ‘Disco Queen’ and ‘Red Cherry Improved’on 10 Nov., and the latter cultivar ratings decreased rapidly for the rest of the test.

FRENCH DWARF —DOUBLE GOLD CLASS.  Plant height ranged from 24 cm (9.4 inches) for ‘Girl Gold’ to 35 cm (13.8 inches) for ‘Hero Gold’. Plant width ranged from 35 cm (13.8 inches) for ‘Girl Gold’ to 45 cm (17.7 inches) for ‘Bonanza Gold Improved’. Flower diameter ranged from 3.9 cm (1.5 inches) for ‘Golden Boy’ to 6.0 cm (2.4 inches) for ‘Safari Gold Improved’. ‘Golden Boy’ (5.6) and ‘Hero Gold’ (5.4) had good foliage ratings all sea-son. ‘Safari Gold Improved’ (3.7) was the only member of this class that failed to have good flower ratings on 17 Nov. It also had a low average foliage (3.8) and flower (3.4) ratings.

FRENCH DWARF —DOUBLE ORANGE CLASS. Plant height was 24 cm (9.4 inches) for ‘Little Hero Orange’ to 37 cm (14.6 inches) for ‘Safari Tangerine’. Plant width ranged from 37 cm (14.6 inches) for ‘Little Hero Orange’ to 54 cm (21.3 inches) for ‘Safari Tangerine’. Flower diameters were from 4.0 cm (1.6 inches) for ‘Orange Boy’ to 6.2 cm (2.4 inches) for ‘Hero Orange’. Most cultivars had good foliage and flowers ratings for the entire evaluation period except for ‘Safari Orange Improved’ (3.1, 3.5) and ‘Safari Tangerine’ (3.0, 3.9) with poor average foliage and flower ratings, respectively.

FRENCH DWARF —DOUBLE YELLOW CLASS. Plant height ranged from 23 cm (9.1 inches) for ‘Little Hero Yellow’ to 36 cm (14.2 inches) for ‘Yellow Jacket’ and ‘Safari Primrose’. Plant width ranged from 38 cm (15.0 inches) for ‘Little Hero Yellow’ to 47 cm (18.5 inches) for ‘Yellow Jacket’. Flower diameters were from 4.1 cm (1.6 inches) for ‘Yellow Boy’ to 6.0 cm (2.4 inches) for ‘Safari Yellow’. ‘Yellow Boy’ and ‘Yellow Jacket’ received high average foliage (5.8) and flower ratings (4.7 to 4.9).‘Girl Primrose’ (5.2) had higher flower ratings with good but significantly lower foliage ratings (4.7) than the former cultivars. ‘Yellow Boy’ (5.3), ‘Yellow Jacket’ (5.2) and ‘Girl Primrose’ (5.0) had significantly higher overall ratings than other cultivars in the class.

FRENCH DWARF —DOUBLE ORANGE/RED CLASS. Plant heights [29 cm (11.4 inches) and 35 cm (13.8 inches)] and widths [41 cm (16.1 inches) and 45 cm (17.7 inches)] were similar for the two cultivars ‘Harmony Boy’ and ‘Safari Bolero’, respectively. ‘Safari Bolero’ [6.3 cm (2.4 inches)] had significantly larger flowers than ‘Harmony Boy’ [4.0 cm (1.6 inches)]. Foliage and overall ratings were not significantly different at all evaluations. ‘Safari Bolero’ (6.0) had significantly better flower ratings than ‘Harmony Boy’(5.0) early in the season (3 Nov. and 10 Nov.), but ‘Harmony Boy’ (5.7 and 5.3) had better flower ratings than ‘Safari Bo-lero’ (2.7 and 2.3) later in the season (23 Nov. and 1 Dec., respectively).

FRENCH DWARF —DOUBLE RED/GOLD CLASS. Plant height ranged from 32 cm (12.6 inches) for ‘Golden Gate’ to 36 cm (14.2 inches) for ‘Safari Queen’ and ‘Safari Red’. Plant width ranged from 42 cm (16.5 inches) for ‘Golden Gate’ to 47 cm (18.5 inches) for ‘Safari Red’, and flower diameters were 6.0 to 6.1 cm (2.4 inches) for ‘Golden Gate’, ‘Safari Queen’, ‘Safari Red’, but neither the differences in plant width nor flower diameter were significantly different.  Foliage ratings were not significantly different among cultivars in all evaluations. ‘Golden Gate’ (5.0), ‘Safari Queen’ (6.0 to 5.0) and ‘Safari Red’ (6.0 to 5.0) had good to very good flower ratings between 3 Nov and 10 Nov., but ratings quickly dropped after that period.

FRENCH DWARF —DOUBLE RED/ORANGE CLASS.  Plant height ranged from 30 cm (11.8 inches) for ‘Hero Harmony’ to 41 cm (16.1 inches) for ‘Safari Scarlet’. Plant width ranged from 40 cm (15.7 inches) for ‘Hero Harmony’ to 49 cm (19.3 inches) for ‘Safari Scarlet’. Flower diameters were similar ranging from 5.2 cm (2.0 inches) for ‘Hero Harmony’ to 6.2 cm (2.4 inches) for ‘Safari Scarlet’. Foliage ratings were not significantly different for cultivars in this class for all evaluations. ‘Hero Harmony’ (5.3) and ‘Safari Scarlet’ (4.7) had higher flower ratings than ‘Hero Flame’ (3.7) on 27 Oct. However, average flower ratings for ‘Hero Flame’ (5.2) and ‘Hero Harmony’ (5.1) were higher than those of ‘Safari Scarlet’ (4.3) by the end of the test.

FRENCH DWARF —DOUBLE RED/YELLOW CLASS. Plant height ranged from 27 cm (10.6 inches) for ‘Bonanza Flame Improved’ and ‘Harmony Girl’ to 30 cm (11.8 inches) for ‘Bonanza Bee Improved’ and ‘Hero Spry’. Plant widths were not significantly different at 37 cm (14.6 inches) for ‘Harmony Girl’ to 45 cm (17.7 inches) for ‘Bonanza Bee Improved’. Flower diameter ranged from 4.7 cm (1.9 inches) for ‘Hero Spry’ to 5.9 cm (2.3 inches) for ‘Harmony Girl’. Foliage ratings were similar for all evaluations except ‘Bonanza Bee Improved’ (3.7) had low foliage ratings on 10 Nov. Flower ratings were good on 10 Nov. for ‘Bonanza Bee Improved’ (5.3) and ‘Hero Spry’, while they were very good for ‘Bonanza Flame Improved’ (6.0) and ‘Harmony Girl’ (6.0).

FRENCH DWARF —DOUBLE YELLOW/ RED CLASS. Plant height ranged from 24 cm (9.4 inches) for ‘Girl Spry’, ‘Hero Bee’, and ‘Little Hero Fire’ to 32 cm (12.6 inches) for ‘Spry Boy’. Plant widths were not significantly different and ranged from 36 cm (14.2 inches) for ‘Hero Bee’ to 42 cm (16.5 inches) for ‘Spry Boy’ and ‘Little Hero Fire’. Flower diameter ranged from 4.0 cm (1.6 inches) for ‘Boy Spry’ to 5.7 cm (2.2 inches) for ‘Hero Bee’. Average foliage ratings for ‘Spry Boy’ (5.7) were significantly better than ‘Girl Spry’ (2.7), ‘Hero Bee’ (3.6), and ‘Little Hero Fire’ (3.8). Average flower ratings were also higher for ‘Spry Boy’ (5.4) than ‘Girl Spry’ (4.7), ‘Hero Bee’ (4.3), and ‘Little Hero Fire’ (4.7). Every weekly foliage and flower rating for ‘Spry Boy’ was better than the other cultivars in the class except on 27 Oct. The flower rating for ‘Girl Spry’ (5.7) was the best on 27 Oct, indicating a superior early performer.

FRENCH —DOUBLE GOLD CLASS. ‘Durango Gold’ [42 cm (16.5 inches)] was significantly taller than than ‘Legend Gold’ [34 cm (13.4 inches)]. Plant width was also significantly greater for ‘Durango Gold’ (49 cm; 19.3 inches) than for ‘Legend Gold’ (46 cm; 18.1 inches). Flower diameter for ‘Durango Gold’ (7.0 cm; 2.8 inches) was significantly greater than ‘Legend Gold’ (5.0 cm; 2.0 inches). ‘Durango Gold’ had significantly higher foliage (6.0) and flower (5.0) ratings Oct. 27 than Legend Gold.  However, ‘Legend Gold’ had significantly higher foliage (4.0 to 6.0) and flower (5.0 to 6.0) ratings on Nov. 17 and 23, and a significantly higher overall rating (5.4) than ‘Durango Gold’ (4.3).

FRENCH —DOUBLE ORANGE CLASS. Plant height was 24 cm (9.4 inches) for ‘Hyper Orange’ and 36 cm (14.2 inches) for ‘Legend Orange Improved’. Plant widths were 36 (14.2 inches) for ‘Hyper Orange’ and 47 cm (18.5 inches) for ‘Legend Orange Improved’. Flower diameters were not significantly different at 4.6 cm (1.8 inches) for ‘Hyper Orange’ and 5.0 cm (2.0 inches) for ‘Legend Orange Improved’. ‘Legend Orange Improved’ had significantly better foliage ratings 23 Oct. (6.0) and 3 Nov. (5.3) compared to ‘Hyper Orange’ ratings of 3.3 and 3.7 for those dates. Flower ratings were not significantly different for all evaluations. Overall ratings were higher for ‘Legend Orange Improved’ (5.2) compared to ‘Hyper Orange’ (4.5).

FRENCH —DOUBLE YELLOW CLASS. ‘Durango Light Yellow’ was 40 cm (15.7 inches) tall and was significantly taller than 'Durango Yellow’ and ‘Hyper Yellow’ at 28 cm (11.0 inches), and ‘Legend Yellow’ at 31 cm (12.2 inches). ‘Durango Light Yellow’ flowers (6.0 cm; 2.4 inches) were significantly wider than ‘Durango Yellow’ (3.7 cm; 1.5 inches), but similar to the other cultivars in this class. There were no significant differences in foliage ratings for all evaluations of these cultivars. The average flowerrating for ‘Hyper Yellow’ (5.2) was significantly better than the ratings for other cultivars in the class, which ranged from 3.8 to 4.3.

FRENCH —DOUBLE RED/YELLOW CLASS. Plant height ranged from 26 cm (10.2 inches) for ‘Hyper Red/Yellow’ to 34 cm (13.4 inches) for ‘Honey-comb’. Plant widths were not significantly different. Flower diameter was 5.7 cm (2.2 inches) for ‘Durango Bee’ and ‘Durango Red’, 4.0 cm (1.6 inches) for ‘Hyper Red/Yellow’, and 5.4 cm (2.1 inches) for ‘Honeycomb’. The average  flower rating was significantly lower for ‘Honeycomb’. However, the overall ratings were not significantly different for the members of this class.

Selecting outstanding cultivars

While early or late season performance, a particular plant height, or shade of the same color may be a selection criteria outweighing seasonal performance, the overall ratings (combined foliage and flower ratings) represent the best view of performance for each cultivar in its class over the entire season. We considered cultivars with an overall rating ≥5 as outstanding, 4 to 4.9 as good performers, and ≤3.9 as fair to poor. The following is a summary of overall performance by class. African dwarf— orange class: ‘Pumpkin Crush’ and ‘Discovery Orange’ performed poorly; African gold class: seven of the eight cultivars were good to outstanding, only ‘Sunspot Gold’ had poor ratings; African— orange class: ‘Mesa Orange’ and ‘Royal Orange’ had outstanding performance ratings, and ‘Antigua Orange’ and ‘Inca Orange’ had similar good ratings. ‘Sunspot Orange’ was the poorest in its class; African—yellow class: ‘Inca Yellow’, ‘Mesa Yellow’, and ‘Perfection Yellow’ had outstanding performance ratings, and ‘American Indian Yellow’ had a similar good rating, while ' Marvel Yellow’ performed poorly; French dwarf—single gold/red class: ‘Disco Granada’ and Disco Marietta’ were similar with good to outstanding performance; French dwarf—single red/gold class: ‘Disco Flame’ and ‘Red Marietta’ were outstanding; French dwarf—double gold class: ‘Golden Boy’ and ‘Hero Gold’ were outstanding and similar to ‘Bonanza Gold Improved’ and ‘Girl Gold’; French dwarf—double orange class: seven of the nine cultivars in this group were good to outstanding, only ‘Safari Orange Improved’ and ‘Safari Tangerine’ were fair; French dwarf—double yellow class: ‘Yellow Boy’, ‘Girl Primrose’ and ‘Jacket Yellow’ were out-standing in the class of nine; French dwarf—double bicolor class: cultivars were not significantly different within the orange/red, red/gold red/orange and red/yellow classes, but  the yellow/red, ‘Spry Boy’ received the highest rating within that class; French double— gold class: ‘Legend Gold’ was outstanding, while ‘Durango Gold’ had a good rating; French—double orange class: ‘Legend Orange Improved’ was outstanding; French—double yellow class: ‘Durango Light Yellow’, ‘Durango Yellow’, ‘Hyper Yellow’ and ‘Legend Yellow’ had good ratings; French—double red/yellow class: ‘Durango Bee’, ‘Durango Red’ and ‘Hyper Red/Yellow’ had outstanding ratings, while ‘Honeycomb’ had a good rating. Those cultivars with the highest overall rating in their class will be considered as standards for comparison with new releases in future tests, thus eliminating the need for reevaluation of so many cultivars. While our irrigation/ soil type/fertilization practices may not represent cultural practices in other landscape situations, our choice of these growing conditions was to provide uniform and satisfactory nutrients and moisture to allow for outstanding growth and flowering of marigolds. Soil amendments and irrigation are typically used in bedding plant trials (Pemberton and Roberson, 2001), and indeed most gardeners and landscapers modify their soil and provide irrigation/fertilizer to maximize growth and flowering. Thus, performance evaluations for bedding plants are more likely influenced by climatic conditions than by culture. We believe these performance evaluations would provide useful information for the bedding plant industry in the southeastern United States or other parts of the world with similar climatic conditions.

Literature cited

American Horticultural Society. 1999. Heat zone map. 29 Apr. 2002. <http://www.ahs.org/publications/heat_zone_map.htm>.

Burpee Seeds and Plants. 1999. The legacy of W. Atlee Burpee. 29 Apr 2002. <http://www.burpee.com/content/articledetail_main.asp?uid=B8B89FEF-5D3E-46E1-A0F4-85A5BB7DEDDD-0&ContentID=497&catID=0&page=1>

Florida Automated Weather Network. 2002. FAWN: Florida Automated Weather Network. 29 Apr. 2002. <http://fawn.ifas.ufl.edu/costomj.html>.

Howe, T.K. and W.E. Waters. 1997. Evaluation of marigold cultivars for the landscape in west-central Florida. Proc. Fla.State Hort. Soc. 110:350–357.

Pemberton, H.B. and W.E. Roberson. 2001. The east Texas bedding plant pack and garden performance trials. HortTechnology 11:392–396.

U.S. Department of Agriculture. 2001. Floricultural crops 2000 summary, April 2001. Natl. Agr. Stat. Serv. Sp Cr 6-1 (01)a.

U.S. National Arboretum. 1990. USDA Plant hardiness zone map. 29 Apr 2002. <http://www.usna.usda.gov/Hardzone/ ushzmap. html?>.

University of Florida, Gulf Coast Research and Education Center, 5007 60th Street East, Bradenton, FL34203.

This research was supported by the Florida Agricultural Expt. Station, and approved for publication as Journal Series R-08788. We thank Nancy West and Gail Bow-man for their excellent technical support.

1 Variety trials coordinator.

2 Professor of floriculture.

HortTechnology
July–September 2002 12(3)