SWEET CORN VARIETY TRIALS

Transcription

1 WESTGATE, FORBES, DARBY: SWEET N TRIALS 13 areas in the state were involved in the study. The five size classifications under consideration were 2, 2, 3,, and 6-dozen stalks crate. Actual stalk count crate most generally was within limits established by U. S. Standards for Celery. Most exceptions were attributable mislabeled. Celery ranged from 55 7 pounds crate, however, the average weight exceeded the esti mated 6-pound billing weight. There was a linear increase in crate weight from the 2-dozen (61 pounds) 6-dozen ( pounds) size. Average stalk diameter for size classifications 2, 2y2, 3,, and 6 was 3.55, 3.17, 2., 2.5, and 2.13 inches respectively; mean stalk weight was 2.53, 2., 1.77, 1.31, and.93 pounds respectively. Frequency distribution curves for each size classi fication plotted for both diameter and weight fol lowed the normal bell-shaped pattern with well defined apex and subtending base. There was considerable overlap between adjacent size classi fications in both stalk weight and diameter. There was a difference between cooars in the size of celery packed. However, no single cooar packed the largest and heaviest stalks when all five size classifications were considered. Regression of celery stalk weight on diameter showed a very close correlation between the two measurements. Theoretical weight-sizing of celery previously packed by conventional methods resulted in a more uniform pack by eliminating over- and under-sized stalks. Data showed weight-sizing be a practical method of sizing celery. LITERATURE CITED 1. Florida Department of Agriculture, Florida Agricultural Statistics, Vegetable Summary. 2. Gull, D. D., Uniformity of Celery Packaging. Florida Agricultural Eximent Stations Annual Report, 1963: United States Department of Agriculture, United States Standards For Celery. SWEET N VARIETY TRIALS AT ZELLWOOD P. J. Westgate, R. B. Forbes, J. F. Darby Horticulturist, Assistant Soils Chemist, and Plant Pathologist Central Florida Eximent Station Sanford The origin of corn has intrigued botanists for centuries. The plant was unknown in the Old World before 192, while in the New World it was the basic food plant of the Inca of South American and the Maya and Aztec of Middle America (6). Remains of prehisric corn have been unccovered from caves in southern Mexico. The earliest remains, dated B.C., are almost certainly those of wild corn. Later remains in clude cultivated corn, and reveal a distinct evo lutionary sequence which gave rise ultimately several still-existing Mexican races of corn. Despite a spectacular increase in size and pro ductiveness under domestication, there has been no substantial change in 7 years in the funda mental botanical characteristics of the corn plant (7). Corn has been considered by botanists as a Florida Agricultural Eximent Stations Journal Series No monotypic genus, its one species being Zea Mays Linn. However, Z. Mays is an extremely variable species, and Sturtevant has proposed seven agri cultural species, including Zea saccharata Sturt. for sweet corn. The first variety of sweet corn recorded in American cultivation was introduced in the region of Plymouth, Massachusetts, from the Indians of the Susquehanna in 1779 (1). From an insignificant beginning in the State of Florida in the early 19's (5), an 1 million dollar crop in (3) in less than two decades, is a striking record for this crop. In 1925 the use of DDT for the control of the corn ear worm was a major breakthrough for the production of sweet corn in Florida. The chemical control of the ear worm made it pos sible offer worm free sweet corn on northern markets. Insect control and the introduction of new high quality, high yielding hybrid sweet corn varieties soon established this crop as a major vegetable crop of Florida. The central Florida area, including plantings in Lake, Orange, and Seminole counties, ac counted for 6,3 s of sweet corn harvested for the season. Most of this age is located on Everglades mucky peat at Zellwood. The tal age of sweet corn harvested for the season in Florida was 9,3 s with 37, s of this tal being grown in

2 1 FLORIDA STATE HORTICULTURAL SOCIETY, 19 Palm Beach County in the Florida Everglades (3). Guzman () has reported on horticultural trials with sweet corn hybrids in the Florida Everglades. Sweet corn from Zellwood in central Florida yielded an average of 229 at an average selling price of $2.7 crate (2 pounds net) for the year (2). Yields and prices for the season continued be good, but the search for better varieties of high yielding, good quality, disease resistant sweet corn goes on, backed up by breeding and testing programs. Eximental Procedure Three one blocks in a field of Zellwin Farms at Zellwood were used for these sweet corn variety trials. On March, 19, soil samples (-6") were taken from this eximental area and analyzed by the Soil Testing Lab., Agricultural Extension Service, Gainesville. This mucky peat showed a ph 6.2 and a Solubridge reading1 of. Available nutrients, extracted with ammonium acetate at ph. were as fol lows: nitrate nitrogen, very low; P2O5, 61 pounds ; K2O, 27 pounds ; CaO, pounds, and MgO, 7 pounds. Block I was planted 5 varieties of sweet corn on March, 19, each variety being planted rows, each feet long. The corn was planted with a hand planter in rows inches apart, and the corn was thinned inches between plants in the row, thus leaving a plant population of 21,7 plants. Block II was planted the same 5 varieties of sweet corn on March 25, 19. Block III was planted 61 varieties on April 21, 19. The following seed sources are listed in Table 1, column 2 under the abbreviations shown in parentheses: Abbot and Cobb (), Asgrow (), Burpee (), Corneli (), Ferry Morse (), Illinois Seed Producers (ISP), J. Harris (), Northrup-King (), Robson (), Roger Bros. (), Seed Research Specialists (), and Emil Wolf, Everglades Eximent Station (EES). The corn plantings were fertilized with one application of 5 pounds of a -1-1 fertilizer, including minors, approximately three weeks after planting. Weeds were chemically i Soluble salts (E.C. x 15) determined by Solubridge in 1:2 soil-water extract. controlled with Randox applied as a spray. DDT and Sevin, in the form of sprays, were used control corn ear worms. No fungicides were used for disease control. Twenty feet of row of each row plot in each block were harvested by hand as each variety matured. The number s and their weight, the average length and diameter of 1 ears, and the average height of 1 stalks for each variety were recorded. The tal of corn were calculated on the basis of 2 pounds s crate (net). Fancy were calculated by figuring the centage of Fancy ears in a sample of 25 ears, and calculating the yield of Fancy from the tal yield. Ears had have at least 6 inches of edible kernels, well filled the tip of the ear, be graded as Fancy. Results and Discussion The earliest maturing varieties, such as Northern Belle () and Gold Cup (), ok 7 days mature when planted on March, 19, while later maturing varieties, such as Silver Queen (), ok days, a 1 day spread between varieties at this early planting date. These early plantings escaped being frozen by a late frost only because they had not come up on the morning the frost occurred. The earliest maturing varieties in the third and last planting (April 21, 19) ok 63 days mature, and the later maturing varieties, days, a spread of only 6 days for the latest planting. A comparison of yields for the three plantings showed that the yield for any one variety tended be constant, even though the earlier plantings ok longer mature than the later plantings. The results of harvest and disease ratings for Block III, planted on April 21, 19, and all harvested by June 29, 19, are given in Table 1. Golden Security (), formerly the favo rite sweet corn variety grown at Zellwood, has been replaced in recent years by Gold Cup () as the favorite yellow variety for this area. Most of the age of sweet corn grown at Zell wood is planted yellow varieties, although there is some white sweet corn grown, principally Silver Queen (). Gold Cup G () out yielded Gold Cup () in the April planting, but of the ears of Gold Cup G showed tips uncovered by the husk. The uncovered tips s detracted from the appearance of the pack, but were not thrown out of grade unless kernels were missing. Gold Cup

3 WESTGATE, FORBES, DARBY: SWEET N TRIALS 15 Table 1. Sweet corn varieties arranged in descending order based on yield. (2 pounds crate net). of Fancy ears calculated L as Variety Seed Source Wt. ear (lbs.) length diara. Uncovered tips s Ht. of Stalk (ft.) Days harvest Shank rot Blight rating -51 Flavor Total Fancy E5C G Gold Cup 11 Gold Cup G. H HOG I Northern Belle Jubilee ko Southern Belle L Northern Belle L # Seneca MK 5 Dark Silk E6C2 139 Sure Crop Seneca MK 11 G. H KVF 6-133^ Seneca MK-1 Florigold Iobelle Iochief Seneca Chief k *H 29*t Arisgold Bantam Evgr Northern Belle Seneca MK 5 White Silk 1 x /63 E * Golden Eagle L Seneca MK Silver Cross Bantam -13 KVF k Seneca Wampum 6l.7k ^ Illiniohief Su Sweet ISP

4 16* FLORIDA STATE HORTICULTURAL SOCIETY, 19 Table 1. (continued) Variety Seed Source Wt. ear (lbs.) length diam. Uncovered tips s Ht. of Stalk (ft.) Days harvest Shank rot Blight rating O-51 Flavor Total Fancy Wintergreen l?l x 1921/63 XP * Northern Belle M Silver Queen 11 x 1921/ I Golden Security 33 Silver Queen Comeli 19 Delamar Gold Cup 97 SKS I White Hybrid #11 Florigold * White Hybrid #31 Snow Cross G. H. 193S I * Florigold A Florigold 17 White Cross Bantam E-357 G. H E-317 Illini Su Sweet Duet Improved Sure Cross I Florigold A # , ' Blight rating based on Ullstrup's scale extending from.25, highly resistant, 5. highly susceptible. G showed this tendency for the tips of the ear outgrow the shuck only in the later planting. Gold Cup did not show this fault in any of the three plantings. A new numbered variety, E5C (), pro duced of Fancy ears, the highest yield in this variety trial. Illinichief Susweet (IFS) and Silver Queen () pro duced sweet corn of outstanding flavor. Northern leaf blight (Helminthosporium turcicum Pass.) ratings were made when the sweet corn varieties reached maturity. The system of rating was based on that recommended by Ullstrup, et al (). The rating scale extended from

5 GUZMAN: CELERY GERMINATION as follows:.25,.5, A rating of.25 represented excellent resistance, as shown by Southern Belle (), and Wintergreen (), and a rating of 5. represented complete susceptibility. The blight occurred under average conditions favorable for its development with high plant population densities, good fertility, adequate moisture, and no fungicide applications. Leaf blight usually reaches its maximum express ion in this area during the first two weeks of July. The blight ratings recorded in Table 1 were made during the latter part of June. The blight in this test did not make its appearance early enough severely affect the yield. Only two of the best 1 varieties based on yield re ceived a blight rating as high as 3., whereas 7 of them were rated at 2. or below. The cent shank rot recorded in Table 1 included any water soaking or discoloration noted at the base of the shank. The cent was ob tained by selecting 25 ears at random from each plot. The cause of this malady was not fully de termined. Spray injury, Helminthosporium (spe cies undetermined), and bacteria were associated with the condition. This malady did not affect the marketable yield since the trouble appeared late, near harvest, and the tips of the shanks are usually cut off during harvest. Summary Sixty-one varieties of sweet corn supplied by seed producers were planted on 3 planting dates from March th April 21, 19, on mucky peat at Zellwood. The planting rate was 21,7 plants. A -1-1 fertilizer, in cluding minors, was used at the rate of 5 pounds. Joseph Harris* Gold Cup, favorite commercial variety for Zellwood, was used as the standard. Seed Research Specialists' variety E5C pro duced the highest yield, (2 pounds net) of Fancy ears. Illinichief Susweet (Illinois Foundation Seeds, Inc.) and Silver Queen (Rogers Brothers Co.) produced sweet corn of outstanding flavor. Shank rot varied from 1, while Ullstrup's Helminthosporium blight ratings ranged from among the various sweet corn varieties. LITERATURE CITED 1. Bailey, L. H. The Standard Cyclopedia of Horticul ture. 1:7-. The Macmillan Co., New York, N.Y Brooke, Donald L. Costs and returns from vegetable crops in Florida. Agr. Econ. Mimeo Report EC-11 p.. Fla. Agr. Exp. Sta., Gainesville, Fla Florida Agricultural Statistics. Vegetable Summary p Fla. Dept. of Agr., Div. of Marketing, Tallahassee, Fla Guzman, V. L. Horticultural trials with sweet corn hybrids. Everglades Exp. Sta. Mimeo Report EES Kelbert, David G. A. Corn-Sweet. Progress by Design. Sunshine State Agricultural Research Report : No. 1 p Agr. Exp. Sta., Gainesville, Fla Mangelsdorf, P. C, and R. G. Reeves. The origin of Indian corn and its relatives. Texas Agr. Exp. Sta. Bull Mangelsdorf, P. C, Richard S. MacNeish, and Waln C. Galinat. Domestication of corn. Science 13: Ullstrup, A. J., Charlotte Elliot, and R. E. Hoppe. Report of the committee on methods for reporting corn disease ratings. U. S. D. A., Div. Cereal Crops and Diseases. Unnumbered mimeo publication. 5 pp SOIL TEMPERATURE EFFECT ON GERMINATION OF CELERY SEED V. L. Guzman Associate Horticulturist Everglades Eximent Station Belle Glade Celery seedbeds are usually planted during the summer and fall months in the organic soils of the Everglades. Shading of the beds with muslin curtains is necessary as celery seed will not germinate under direct sunlight during the hot months of the year (1, 3). Since the muck is Florida Agricultural Eximent Stations Journal Series No an opaque black body, it was postulated that radiation absorption is sufficient raise the temature of the soil long enough prevent germination or kill the celery seed embryo. It is also possible that high light intensity or the combination of light and temature prevents germination. Under natural conditions it is diffi cult, if not impossible, separate the effect of light from temature since they come as ra diant energy from the sun. It was felt, how ever, that temature was more important than light. A series of eximents was conducted ascertain the maximum temature at which celery seed germinate. This threshold value will be used for screening shade materials that may