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93 -* UNIVERSITY OF 3 UN IVRSITY OF Gulf Coast Research and Education Center FLO R DA 5007 60th Street East, Bradenton, FL 34203 Bradenton GCREC Research Report BRA1993-20 Institute of Food and Agricultural Sciences September 1993 it:rstn Science STANDARD WATERMELON VARIETY EVALUATION SPRING 1993i i D. N. Maynard1 """ --siy Of o F . Standard watermelons weigh from 18 to 35 lbs and represent most of the commercial crop grown in Florida. Icebox watermelons weigh 6 to 12 Ibs each and are grown on a small acreage. Seedless watermelons, weighing 12 to 18 Ibs, also are grown in Florida on a limited scale. Florida produced 9 million cwt of watermelons of all types from 45,000 harvested acres in 1991-92 which provided an average yield of 200 cwt/acre. The average price was $6.95/cwt providing a crop value exceeding $62 million which accounted for 3.6% of the gross returns to the state's vegetable growers (Freie and Young, 1993). Until recently, the Florida crop was about equally divided among open pollinated and hybrids of the Crimson Sweet, Charleston Gray, and Jubilee types. A noticeable decline in Charleston Gray and Jubilee production has been replaced largely by increased acreage of Allsweet and blocky Crimson Sweet types. The purpose of this trial was to evaluate some of the recently introduced varieties, hybrids, and experimental lines of the Crimson Sweet, Jubilee, and Allsweet standard types. Materials and Methods Soil samples from the experimental area obtained before fertilization were analyzed by the University of Florida Extension Soil Testing Laboratory (Hanlon and DeVore, 1989): pH = 7.2 and Mehlich I extractable P = 117, K = 23, Mg = 125, Ca = 836, Zn = 9.1, Cu = 7.2, and Mn = 8.0 ppm. The EauGallie fine sand was prepared in early February 1993 by incorporation of 0-1.2-0 lb N-P20O-K20 per 100 linear bed feet (Ibf). Beds were formed and fumigated with methylbromide:chloropicrin, 67:33 at 2.3 lb/100 Ibf. Banded fertilizer was applied in shallow grooves on the bed shoulders at 2.7-0-3.8 lb N-P205-K20/100 Ibf after the beds were pressed and before the black polyethylene mulch was applied. The total fertilizer applied was equivalent to 130-60-182 lb N-P 0 -K20/acre. The final beds were 32 in. wide and 8 in. high and were spaced on 9 ft centers, with four beds between seepage irrigation/drainage ditches which were on 41 ft centers. The standard watermelons were planted in rows adjacent to the ditches to serve as pollenizers for seedless watermelons that were being evaluated in the two center beds of each land. 'Professor and Vegetable Extension Specialist. Twenty-five standard watermelon entries (Table 1) were direct-seeded on 16 February in holes punched in the polyethylene at 3 ft in-row spacing. Experimental line plots had six plants each and named variety plots had eight plants each; both were replicated three times in a randomized, complete block design. Weed control in row middles was by cultivation and applications of paraquat. Pesticides were applied as needed for control of sweetpotato whitefly endosulfann and esfenvalerate) and gummy stem blight (chlorothalonil and metaxyl- chlorothalonil). The watermelons were harvested on 7, 15 and 28 June. Marketable melons (U.S. No. 1 or better) according to U.S. grades (U.S. Standards for Grades of Watermelons, 1978) were separated from culls and counted and weighed individually. Soluble solids determinations were made with a hand-held refractometer on two to six fruit of each entry at each harvest, and the incidence of hollowheart was recorded on two to eight fruit. The resulting data were subjected to analysis of variance and mean separation was by Duncan's multiple range test. Results and Discussion February, March, April, and May of 1993 were slightly cooler than the 39-year average (Stanley, 1993) while June was somewhat warmer (Table 2). Except for April, rainfall in the spring of 1993 was less than for the 39-year average. Aside from the 'storm of the century' on 13-14 March which caused extensive plant loss, there were no serious adverse weather effects on the watermelon crop. Early yields, representing the first of three harvests, ranged from 0 for 'Summer Flavor 400' to 304 cwt/acre for 'Rebel Queen' (Table 3). Fifteen other entries had early yields similar to those of 'Rebel Queen.' Average fruit weight of early-harvested watermelons ranged from 15.4 lb for XPH 6190 to 25.8 lb for 'StarBrite'. Five other entries had early fruit weight similar to that of 'StarBrite' while ten entries had early fruit weight similar to that of XPH 6190. The incidence of hollowheart ranged from 0 in 'Crimson Tide', RXW 105, 'Royal Sweet', and 'Regency' to 67% in 'StarBrite', however, this difference was not significant. Width of cracks as a measure of the severity of hollowheart ranged from 0 for those entries listed as having 0 hollowheart to 1.38 in. for RXW 104. Total yields, representing three harvests, ranged from 637 cwt/acre for XPH 6159 to 1026 cwt/acre for 'StarBrite' (Table 3). Five other entries had total yields similar to 'StarBrite' while 17 other entries had total yields similar to those of XPH 6159. Average fruit weight for three harvests ranged from 17.2 lb for 'Royal Majesty' and XPH 6190 to 24.9 lb for 'Summer Flavor 610'. Soluble solids ranged from 11.1% for RXW 105 to 13.0% for 'Sultan'. Soluble solids in all entries exceeded the 10% specified for optional use in the U.S. grade standards (U.S. Standards for Grades of Watermelons, 1978). The incidence of hollowheart for the entire season ranged from 6% for 'Crimson Tide' and XPH 6194 to 57% in 'Rebel Queen'. The severity of hollowheart ranged from 0.11 in. cell separations in XPH 6144 to 1.73 in. separations in 'Regency'. The hollowheart data was based on cutting from two to eight fruit per entry at each harvest. The variation is caused by the unequal number of fruit harvested at each harvest date. According to U.S. watermelon grades, the aggregate width of cracks in a long melon cannot exceed 1.25 in. in width and in a round melon cannot exceed 2 in. in width to qualify for the U.S. No. 1 grade, except for the 10% tolerance which is permitted (U.S. Standards for Grades of Watermelon, 1978). The proportion of fruit that was 12 lb or less ranged from 0 to 9%, but was not statistically different among the entries (Table 4). These fruit could not be marketed commercially. The proportion of fruit between 12 and 18 lb ranged from 8% for 'Mirage' to 69% for 'Rebel Queen'. Fourteen other entries had a similar proportion of fruit in this weight class as 'Mirage', while six other entries had a proportion similar to 'Rebel Queen'. The proportion of fruit weighing between 18 and 26 lb ranged from 20% for RXW 105 and five other entries to 73% for 'Crimson Tide' and 14 other entries. There were no 'Rebel Queen' fruit exceeding 26 lb, whereas 36% of the 'Summer Flavor 610' fruit weighed more than 26 lb. Watermelon yields and quality were considerably higher than those obtained in 1991 when gummy stem blight severely restricted yields (Maynard, 1991) and in 1992 when yields were restricted by a vine decline from an undetermined cause (Maynard, 1992). Overall yields were three to five times the state average yield (Freie and Young, 1993). Note The information contained in this report is a summary of experimental results and should not be used as recommendations for crop production. Where trade names are used, no discrimination is intended and no endorsement is implied. Literature Cited Freie, R. L. and H. V. Young. 1993. Florida Agricultural Statistics. Vegetable Summary. Florida Agricultural Statistics Service, Orlando. Hanlon, E. A. and J. M. DeVore. 1989. IFAS Extension Soil Testing Laboratory Chemical Procedures and Training Manual. Fla. Coop. Ext. Circ. 812. Maynard, D. N. 1991. Standard watermelon variety evaluation. GCREC Res. Rept. BRA1991-18. Maynard, D. N. 1992. Standard and icebox watermelon variety evaluation. Spring 1992. GCREC Res. Rept. BRA1992-19. Stanley, C. D. 1993. Temperature and rainfall report for 1992. GCREC Res. Rept. BRA1993-1. U.S. Standards for Grades of Watermelons. 1978. U.S.D.A., AMS, Washington, DC. Table 1. Standard hybrid watermelon entries, fruit descriptions, and seed sources. Gulf Coast Research and Education Center. Spring 1993. Entry Description Source Elongated, blocky. Medium green American Sunmelon Crimson Tide Fiesta Huck Finn Mirage Rebel Queen Regency Royal Majesty Royal Star Royal Sweet RXW 104 RXW 105 RXW 106 Sangria Oval. Distinct, broken dark-green stripes on light-green background. Crimson Sweet type. Elongated. Indistinct light-green stripes on dark-green background. Allsweet type. Oblong. Indistinct dark-green stripes on a medium-green background. Oblong. Dark-green stripes on a light-green background. Oblong, blocky-round. Narrow dark- green stripes on a mottled, darker- green background. Oblong. Indistinct, dark-green stripe on a light-green background. Elongated. Narrow, light-green stripes on very dark-green back- ground. Allsweet type. Oblong, blocky. Dark-green stripe on light-green background. Oblong. Wide, dark-green stripes on light-green background. Blocky, oval. Indistinct, wide dark-green stripes on light-green background. Blocky. Indistinct, wide dark-green stripes on light-green background. Elongated. Indistinct, light-green stripes on dark-green background. Allsweet type. Elongated. Light-green stripes on dark-green background. Allsweet type. Rogers NK Rogers NK Ferry-Morse Asgrow Ferry-Morse Petoseed Petoseed Petoseed Petoseed Rogers NK Rogers NK Rogers NK Rogers NK ASM 6564 Table 1 (cont.) Entry Description Source StarBrite Oblong. Distinct dark-green stripes on light-green background. Royal Sweet type. Asgrow Sultan Blocky, oval. Medium-green stripes light-green background. Summer Flavor 400 Summer Flavor 410 Summer Flavor 610 XPH 6144 XPH 6159 XPH 6188 XPH 6189 XPH 6190 XPH 6194 Blocky, oblong. Wide, dark-green stripes on light-green background. Blocky, stripes oblong. Wide, dark-green on light-green background. Oblong. Wide, dark-green stripes on light-green background. Elongated. Indistinct, light-green stripes on dark-green background. Allsweet type. Oval. Distinct, dark-green stripe on very light-green background. Elongated. Very narrow, light-green stripe on dark-green background. Allsweet type. Elongated. Narrow, light-green stripe on dark-green background. Allsweet type. Elongated. Narrow, light-green stripes on very dark-green background. Allsweet type. Oval. green Dark-green stripe on light- background. Harris Moran Abbott & Cobb Abbott & Cobb Abbott & Cobb Asgrow Asgrow Asgrow Asgrow Asgrow Asgrow 6 Table 2. Temperature and rainfall at the Gulf Coast Research and Education Center for 16 February to 28 June, 1993 and 39-year monthly averages (Stanley, 1993). Average Temperature (OF) 1993 39-year average Rainfall (in.) Month (date) Max. Min. Max. Min. 1993 39-year average Feb. (16-28) 72 50 74 52 1.75 3.22 March 75 55 77 55 2.33 3.40 April 80 57 82 60 4.33 1.68 May 86 64 87 64 1.53 3.16 June (1-28) 93 70 89 70 3.66 7.97 '1993 data are for the dates shown, 39-year averages are for the entire month. Table 3. Early and total yield, average fruit weight, soluble solids, and the incidence and severity of hollowheart of standard watermelons. Gulf Coast Research and Education Center. Spring 1993. Early Harvest' Total Harvest Average Hollow Hollow Average Soluble Hollow Hollow Weight fruit heart heart Weight fruit solids heart heart Entry (cwt/A)2 wt (Ib) (%) (in.)3 (cwt/A)2 wt (Ib) (%) (%) (in.)3 StarBrite 123 a-d4 25.8 a 67 a 0.24 de 1026 a 23.7 a-c 11.5 c-f 53 ab 0.36 b-d XPH 6144 187 a-d 20.9 b-e 33 a 0.12 e-g 992 ab 21.2 b-h 11.5 c-f 17 bc 0.11 d Mirage 48 cd 24.0 a-c 17 a 0.08 fg 953 a-c 24.2 ab 11.8 b-f 17 bc 0.33 b-d Crimson Tide 72 b-d 17.8 e-g 0 a 0.00 g 932 a-d 20.7 c-j 11.9 b-f 6 c 0.59 b-d Huck Finn 154 a-d 23.3 a-c 33 a 0.16 d-g 913 a-e 22.0 a-f 11.8 b-f 33 a-c 0.20 d RXW 105 226 a-c 19.6 c-g 0 a 0.00 g 866 a-f 19.4 f-j 11.1 f 7 c 0.24 d RXW 104 204 a-c 21.0 b-e 17 a 1.38 a 831 b-g 19.8 e-j 11.8 b-f 11 c 0.75 b-d Summer Flavor 610 91 b-d 20.2 c-f 33 a 0.08 fg 824 b-h 24.9 a 11.9 b-f 24 a-c 0.80 b-d XPH 6194 175 a-d 22.6 a-d 17 a 0.12 e-g 815 b-h 18.5 f-j 11.4 d-f 6 c 0.12 d Fiesta 209 a-c 16.8 e-g 33 a 0.30 d 797 c-h 18.2 h-j 11.7 b-f 22 a-c 0.22 d Sangria 150 a-d 17.3 e-g 17 a 0.12 e-g 794 c-h 19.1 f-j 12.5 a-c 33 a-c 0.20 d Summer Flavor 400 0 d 787 c-h 23.4 a-d 12.3 a-d 42 a-c 0.47 b-d Royal Sweet 28 cd 21.0 b-e 0 a 0.00 g 786 c-h 21.8 a-g 11.4 d-f 8 c 0.16 d ASM 6564 135 a-d 17.0 e-g 17 a 0.04 fg 758 d-h 18.5 f-j 11.1 ef 17 bc 0.12 d Sultan 144 a-d 20.4 b-f 17 a 1.22 b 744 e-h 21.0 b-i 13.0 a 37 a-c 1.13 a-c XPH 6190 261 ab 15.4 g 17 a 0.59 c 743 e-h 17.2 j 11.7 b-f 17 bc 0.31 cd Royal Star 97 b-d 20.5 b-f 17 a 0.16 d-g 739 e-h 23.5 a-d 11.9 b-f 42 a-c 1.18 ab Royal Majesty 132 a-d 16.6 e-g 33 a 0.69 c 738 e-h 17.2 j 12.0 b-f 30 a-c 0.56 b-d Regency 30 cd 22.7 a-d 0 a 0.00 g 732 e-h 23.7 a-c 12.2 a-d 15 bc 1.73 a Summer Flavor 410 50 cd 24.8 ab 33 a 0.10 e-g 699 f-h 23.1 a-e 12.1 b-e 31 a-c 0.69 b-d RXW 106 192 a-d 17.9 e-g 17 a 0.12 e-g 682 f-h 20.1 d-j 12.1 b-e 28 a-c 0.13 d XPH 6188 181 a-d 18.2 e-g 17 a 0.20 d-f 680 f-h 18.6 f-j 12.1 b-e 17 bc 0.16 d XPH 6189 213 a-c 20.2 c-f 17 a 0.20 d-f 669 gh 20.3 c-j 11.7 b-f 33 ac 0.22 d Rebel Queen 304 a 16.0 fg 33 a 0.18 d-f 639 h 17.5 ij 11.9 b-f 57 a 0.28 cd XPH 6159 86 b-d 16.5 e-g 50 a 0.56 c 637 h 18.3 g-j 12.5 ab 52 ab 0.72 b-d 'Early harvest represents the first of three harvests. 2Acre = 4840 Ibf. 3Average width of fruit cracks in fruit with hollow heart. Mean separation in columns by Duncan's multiple range test, 5% level. Table 4. Fruit weight distribution of the total yield of standard watermelons. Gulf Coast Research and Education Center. Spring 1993. Fruit Weight (Ib) <12.0 12.1-18.0 18.1-26.0 >26 Entry Percentage of fruit ASM 6564 7 a' 45 a-f 46 b-f 2 f Crimson Tide 0 a 21 f-j 73 a 6 ef Fiesta 2 a 49 a-e 47 b-e 2 f Huck Finn 1 a 20 f-j 63 a-d 16 b-f Mirage 0 a 8 j 57 a-d 35 ab Rebel Queen 9 a 69 a 22 fg 0 f Regency 0 a 17 h-j 55 a-d 28 a-d Royal Majesty 4 a 66 ab 29 e-g 1 f Royal Star 0 a 10 j 66 a-c 24 a-e Royal Sweet 0 a 23 f-j 60 a-d 17 a-f RXW 104 4 a 32 c-j 55 a-d 9 d-f RXW 105 4 a 56 a-c 20 g 20 a-f RXW 106 9 a 29 d-j 51 a-e 11 c-f Sangria 5 a 36 c-i 46 b-f 13 c-f StarBrite 0 a 22 f-j 47 b-f 31 a-c Sultan 0 a 25 e-j 69 ab 6 ef Summer Flavor 400 0 a 19 g-j 54 a-d 27 a-d Summer Flavor 410 0 a 14 ij 57 a-d 29 a-d Summer Flavor 610 0 a 15 h-j 49 a-e 36 a XPH 6144 2 a 31 c-j 50 a-e 17 a-f XPH 6159 2 a 52 a-d 41 c-g 5 ef XPH 6188 7 a 41 b-h 49 a-e 3 f XPH 6189 3 a 31 c-j 55 a-d 11 c-f XPH 6190 8 a 50 a-e 39 a-e 3 f XPH 6194 8 a 43 b-g 38 d-g 11 c-f 'Mean separation in columns by Duncan's multiple range test, 5% level. |