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Dep. Hortic. Sci., North Carolina State Univ., Raleigh, NC 27695-7609. The research was funded in part by the North Carolina Agricultural Research Service (NCARS)
* Corresponding author (todd_wehner{at}ncsu.edu)
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ABSTRACT |
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 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSNOTESRESULTS AND DISCUSSIONCONCLUSIONSREFERENCES |
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INTRODUCTION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSNOTESRESULTS AND DISCUSSIONCONCLUSIONSREFERENCES |
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Cucumber is grown as a number of different types and is used as either a fresh or processed vegetable. Some of the types of cucumber grown throughout the world are American pickling, European pickling, American slicing (fresh market), European greenhouse (parthenocarpic), oriental trellis, middle-eastern (Beit Alpha), and schalgurken. Cucumber types differ based on the type of use (fresh market or processed), fruit length, diameter, color, color uniformity, skin thickness, and skin surface protrusions. In the United States in 1998, 17 264 ha were planted to pickling cucumber with a total production of 615 310 Mg of fruit (USDA, 1998). The total area and production of slicing cucumber for 1997 was 9760 ha with a production of 202 514 Mg (USDA, 1998). Cucumber is the second most important vegetable crop in North Carolina, with a production area of 
9717 ha (USDA, 1997). Nationally, North Carolina was ranked third in pickling cucumber production after Michigan and Florida, and fifth in slicing cucumber production after Georgia, Florida, Michigan, and California during 1997 (USDA, 1997).
Breeding for yield in cucumber has been one of the important objectives of many cucumber breeding programs since the 1900s (Wehner, 1989). Yield of pickling cucumber has been improved by breeding for disease resistance (Peterson, 1975), as well as through the use of improved cultural practices (Cargill et al., 1975). Increased yield of cucumber cultivars has been due also to the improvement of qualitative traits such as gynoecious sex expression, improved fruit color (improved percentage marketable fruit), and direct yield improvement (Wehner, 1989).
The average yield of pickling cucumber in the United States (USDA, 1959–1998) has increased by 100% across the last four decades due to improved cultural practices, and selection for yield and disease resistance. Most of the productivity increase was during the first two decades, with a plateau in the last two decades. Thus, there is a need to focus more on yield improvement. To identify new sources of high yield in the cucumber germplasm collection for use in breeding, we are using a three-stage process: First, all available plant introduction accessions, cultivars, and breeding lines (hereafter collectively referred to as cultigens) are tested for combining ability with a gynoecious tester; second, all available cultigens are tested for yield per se; and third, the best cultigens are evaluated using larger trials with multiple harvests, seasons, and years.
Measurement of the yield of a large and diverse set of cucumber cultigens is costly. Previous research has provided some guidelines for the design of efficient yield trials. Fruit number was found to be a more stable measure of productivity than fruit weight or value in a once-over harvest trial for cucumber (Ells and McSay, 1981). Fruit number was more highly heritable (0.17) than fruit weight (0.02) (Smith et al., 1978). Evaluation of yield in single-plant hills was poorly correlated with multiple-harvest yield in replicated field trials, indicating the necessity for testing in row plots (Wehner and Miller, 1984; Wehner, 1986). In addition, greenhouse evaluation for yield based on fruit number on single plants was not correlated (r = 0.09 to 0.15) with yield at two field locations (Nerson et al., 1987).
Once-over harvest trials having three replications were recommended for maximum efficiency to determine which cucumber lines should be tested further in multiple-harvest trials (Wehner and Miller, 1984; Wehner, 1986). A plot size of 1.2 x 1.5 m was found to be optimum for yield evaluation for once-over harvest of pickling cucumber cultigens harvested using paraquat (1,1'-dimethyl-4,4'-bipyridinium ion; Swallow and Wehner, 1986). In cucumber, small-plot, single-harvest trials were found to be more efficient than large-plot, multiple-harvest trials (Wehner, 1986, 1989). Wehner et al. (1984) recommended the use of paraquat to defoliate plots for efficient yield measurement in once-over harvest trials.
Swallow and Wehner (1989) calculated that maximum efficiency was achieved by allocating test plots of cucumber cultigens to different seasons and years rather than locations and replications. Another study showed that yield evaluation at the Clinton location was more efficient (information relative to cost) than three other North Carolina locations tested (Wehner, 1987).
Miller and Hughes (1969) reported that harvesting at 14 to 31% oversized fruit stage in a plot was found to be optimum for maximum value in once-over harvest for ‘Piccadilly’ and ‘Southern Cross’ gynoecious pickling hybrids in North Carolina. Oversize is >51-mm diameter for pickling and >60-mm diameter for slicing cucumber. Chen et al. (1975) used a computer simulation and reported that plots harvested at 10% oversized fruit stage gave an optimum yield for Piccadilly hybrid under North Carolina conditions. Colwell and O'Sullivan (1981) reported that the optimum harvest stage to maximize yield for ‘Femcap’ and ‘Greenstar’ gynoecious hybrids occurred when 5 to 15% of fruit in a plot were oversized. Studies using a diverse array of pickling and slicing cucumber cultigens revealed no effect on fruit yield and quality traits (with the exception of early yield of pickling type) between harvesting cucumber when fruit in a plot reached 10 or 50% oversized fruit stage (Shetty, 1999).
Cucumber plants produce one or more of three types of flowers: staminate, pistillate, and perfect. Exogenous application of ethylene is known to promote the production of pistillate flowers in monoecious cucumber lines, resulting in increased fruit yield (McMurray and Miller, 1968; Robinson et al., 1968; Miller et al., 1970; Rudich et al., 1972; Hogue and Heeney, 1974; Cantliffe and Phatak, 1975). Ethephon treatments significantly improved the total yield, percentage of culled fruit, and fruit quality traits evaluated in pickling cucumbers (Shetty, 1999). Shetty (1999) observed higher total yields with a single ethephon application and did not observe an additional benefit beyond a single application at the first-true-leaf stage.
Ethephon also was found to have an effect on vegetative and floral traits (days to first flower set, days to 50% flower set, days to first fruit set, days to 50% fruit set, and fruit quality in a group of cucumber cultigens which differed in their sex expression. This study also concluded that one application of ethephon was optimum. More ethephon applications usually increased the number of days to reach a particular growth stage (days to first flower set, days to 50% flower set, days to first fruit set, and days to 50% fruit set). However, ethephon did not have an effect on fruit yield and quality traits on a set of slicing cucumber cultigens (Shetty, 1999). Ethephon treatment of isogenic lines of cucumber differing in sex expression improved gynoecious rating, fruit number (total, early, and marketable), and fruit weight (total, early, and marketable) compared with the untreated control. Ethephon was effective in increasing pistillate flower number on monoecious inbreds, but had little effect on gynoecious inbreds.
The objective of this experiment was to evaluate all available cucumber cultigens in the USDA germplasm collection for fruit yield and quality under field conditions in North Carolina.
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MATERIALS AND METHODS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSNOTESRESULTS AND DISCUSSIONCONCLUSIONSREFERENCES |
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Plots were 1.2-m long and 1.5-m wide with 1.2-m alleys at each end. Plots were planted with 16 seeds and thinned to a uniform stand of 12 plants per plot. Recommended horticultural practices (Schultheis, 1990) were used for all experiments. Fertilizer was incorporated before planting at a rate of 90-39-74 kg ha-1 (N-P-K), with an additional 34 kg ha-1 N applied at the vine tip-over stage. Curbit [ethalfluralin N-ethyl-N-(2-methyl-2-propenyl)-2,6-dinitro-4-(trifluoromethyl)benzenamine] was applied for weed control. Irrigation was applied when needed for a total (irrigation plus rainfall) of 25 to 40 mm per week. ‘Sumter’ pollenizer was planted in side rows and end plots to provide additional pollen and border competition for the test plots.
No disease problems were observed in the spring season of either year. Some foliar diseases were observed in the plots during the summer season, but symptoms were mild due to the routine spray program followed as part of recommended cultural practices (Schultheis, 1990). Each plot was harvested once-over when the plants had 15% oversized fruit. Although the usual index for yield evaluation for testing populations in our breeding program is 10%, we used a 15% index in this study to avoid penalizing low yielding or late-maturing cultigens.
Ethephon was applied at the first to second true leaf stage (approximately one month after planting). A backpack sprayer at 100 to 140 kPa (15 to 20 psi) was used to spray the ethephon on the leaves until run-off. Ethephon was prepared using Florel (3.9% ethephon, Southern Agricultural Insecticides, Inc., Palmetto, FL)1 at the rate of 2.5 mL L-1.
Data were collected as plot means, and consisted of number of total, early, and cull fruit per plot. Early fruit were the number of oversized fruit at harvest. The number of marketable fruit was calculated as total - cull. Percentage of culls was calculated as 100 x cull fruit number/total fruit number. Similar formulas were used to compute percentage of early (by weight and by number) fruit and percentage (by weight and by number) of marketable fruit. Fruit weight was recorded for all grades (early, marketable, cull, and total) during the spring season of 1997. In all other environments, only total fruit weight was recorded. In those environments, early, marketable, and cull fruit weights were estimated from early, marketable, and cull fruit number along with total fruit weight using regression relationships from the spring season (Shetty, 1999).
Fruit quality was rated, based on fruit color and shape, on a 1 to 9 scale (1–3 = poor overall with curved and tapered shape and nonuniform light green color; 4–6 = intermediate; 7–9 = excellent overall with straight, cylindrical, and blocky shape and uniform dark green color). Thus, the scale has three main levels, with three sublevels in each, resembling a +/- system (7 = excellent-, 8 = excellent, 9 = excellent+). Days to harvest and fruit quality rating were also recorded. All cultigens were grouped into one of four types: pickling, slicing, middle-eastern (Beit Alpha), and oriental trellis. Digital photographs of fruit of all cultigens used in the study were recorded to verify fruit type.
The experiment was a randomized complete block design with 817 cultigens, two seasons (spring, summer), two years (1997, 1998), and three replications. The two years and two seasons were considered to be four environments to simplify the statistical analysis. Data were analyzed using GLM procedures of SAS 6.12 (SAS Institute, Inc., Cary, NC). Yield was expressed as thousands of fruit ha-1 for fruit number, and Mg ha-1 for fruit weight to make comparisons with other studies easier. Plots with a stand count (plant number) of <50% were eliminated from the statistical analysis, and plots with stand count ranging from 50 to 75% of target stand (12 plants) were corrected using the formula:
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RESULTS AND DISCUSSION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSNOTESRESULTS AND DISCUSSIONCONCLUSIONSREFERENCES |
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The main effect of environment was not significant for any traits except percentage marketable fruit weight (Table 2) . There were significant differences among the 817 cultigens for fruit yield and quality, and for days to harvest. The interaction of cultigen and environment was significant for all traits, except percentage of culls. However, the effect of cultigen was much larger than that of cultigen x environment for all the traits (Table 2). Therefore, fruit yield and quality traits are presented as averages across the three environments.
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Pickling Cucumber
Forty-seven cultigens produced higher yields (total fruit number) than the highest yielding check Calypso. The cultigens with the highest fruit number were PI 215589, PI 344440, PI 356809, PI 370643, PI 249561, PI 209065, PI 288992, PI 179678, PI 531314, and PI 422191. PI 215589 produced 267 thousand fruit ha-1, compared with Calypso, with 105 thousand fruit ha-1. PI 209065 (USA OH) and PI 531314 (Hungary) were the only two cultigens with both a higher fruit number and fruit weight than Calypso (Table 3).
Cultigens with the highest early fruit weight were PI 209065, PI 285610, PI 175111, PI 137848, PI 264666, PI 269481, PI 306180, PI 370019, PI 482463, PI 211728, and PI 163216. All yielded more than 20 Mg ha-1. Only 21 cultigens had higher early yield than the best check, Calypso. A total of 68 cultigens had a higher early yield percentage (by weight) than the best check cultivar, Sumter. PI accessions of pickling type that had the highest early yield percentage (by weight) were PI 211728, PI 512336, PI 175121, PI 500359, PI 344432, PI 370447, PI 163218, PI 163216, PI 212896, and PI 512607. Cultigens with higher early fruit weight and higher early yield percentage (by weight) than the best checks were PI 174160, PI 175111, PI 175121, PI 209065, PI 269481, PI 285610, PI 344432, and PI 370019.
Thirty PI accessions had higher early yields (by number), and 111 PI accessions had higher early yield percentage (by number) than the best check, Calypso. PI accessions with the highest early yield (by number) were PI 209065, PI 422191, PI 531314, PI 169397, PI 215589, PI 379278, and PI 269480. All were estimated to produce more than 66 thousand fruit ha-1. Cultigens with the highest early yield percentage (by number) were PI 500359, PI 222986, PI 370447, PI 175120, PI 175121, PI 217946, PI 512607, and PI 221440. All had >70% of yield in numbers as early yield. Cultigens with both high early fruit yield and high early yield (by number) compared with the checks were PI 169397, PI 209065, PI 212985, PI 263047, PI 263079, PI 269480, PI 269481, PI 326597, PI 330628, PI 370019, PI 379278, PI 390954, PI 422191, PI 458855, PI 458856, PI 504567, and PI 512620. PI 269481 was the only cultigen that had high early yield (number and weight) and had a high percentage of early yield (number and weight) (Table 3).
There were cultigens with marketable yields (by weight) higher than the best check, Calypso. Cultigens producing >5 Mg ha-1 marketable fruit were PI 326598, PI 197087, PI 478367, PI 206043, PI 326596, PI 512597, PI 531312, PI 169397, PI 379278, PI 209065, PI 531309, PI 271753, and PI 531314. There were 88 cultigens with a higher marketable yield percentage (by weight) than the best check, Calypso. Cultigens with both high marketable weight and high marketable yield percentage (by weight) were PI 197087, PI 206043, PI 271753, PI 326596, PI 326598, PI 379278, PI 478367, PI 512597, PI 531309, and PI 531312 (Table 3).
There were 72 cultigens with higher marketable yield (by number) and 101 cultigens with higher marketable yield percentage (by number) than the best check, Calypso (33 thousand fruit ha-1). Cultigens with high marketable fruit number were PI 215589, PI 179678, PI 288992, PI 249561, PI 267087, PI 356809, PI 205995, PI 344440, PI 292012, PI 390953 (all >53 thousand fruit ha-1). Those with high marketable yield percentage (by number) were PI 179678, PI 215589, PI 200815, PI 164734, PI 532162, PI 288992, PI 135122, PI 267087, PI 264226, and PI 482463 (all >50%). Pickling cultigens ranked in the top 10% category for high marketable fruit number and high marketable yield percentage (by number) were PI 179678, PI 215589, PI 267087, and PI 288992 (Table 3).
A total of 100 pickling PI accessions had a lower culled fruit percentage (by weight) than the best check Calypso. Calypso had lower cull weight than the other pickling check, Sumter, for total cull fruit weight but had the same culled fruit percentage (by number). There were 114 cultigens with a lower percentage of culled fruit than Calypso. Cultigens which ranked in the top 10% for fewest number and weight of culls were PI 135122, PI 175121, PI 283902, PI 289698, PI 370447, PI 504570, PI 512634, PI 512637, PI 512640, and PI 532162 (Table 3). In general, the PI accessions evaluated had poor fruit quality ratings compared with the standard checks used in the study. Four pickling cultigens had similar or better ratings for fruit quality: PI 422180, PI 422182, PI 506461, and PI 435947 (Table 3).
There were 36 cultigens that required fewer days to harvest than Calypso. The best one (PI 343452) was 4 d earlier than Calypso. The latest one (PI 512336) required 28 d more than Calypso to harvest. The earliest cultigens were PI 205995, PI 271334, PI 164816, PI 531309, PI 342950, PI 257486, PI 351139, PI 164819, PI 264226, PI 267746, PI 137848, and PI 343452 (Table 3).
The cultigens with the highest total yield in terms of fruit weight among the pickling cucumber cultigens evaluated in the study were PI 209065, PI 326598, PI 137848, PI 285610, and PI 264666. There were 17 cultigens that produced higher total fruit weight than the check cultivar Calypso. In general, all 17 cultigens identified had higher or similar early and marketable fruit weight and number than Calypso. However, fruit quality ratings were lower for the 17 cultigens. In general, the number of days to harvest for the 17 cultigens also was higher than for Calypso. The lowest yielding cultigens in the study were PI 179921, PI 163222, PI 222986, PI 164465, and PI 481612, which also showed low fruit quality rating and high number of days to harvest (Table 3).
Slicing Cucumber
Nine cultigens had more fruit weight than the high yielding slicing check ‘Sprint 440’. Four cultigens, PI 234517, PI 118279, PI 304085, and PI 512614, also had higher total fruit number than the check. The nine cultigens were similar for early, marketable, and cull fruit weight. However, PI 118279 from Brazil had a high number of total, early, and marketable fruits with fruit weight similar to the other eight PI accessions identified, but had smaller size. The nine cultigens identified were similar for days to harvest with the exception of PI 304805 and PI 368560, which took 8 d longer. The fruit quality ratings for the nine cultigens were lower than the checks, Sprint 440 and ‘Dasher II’. Of the check cultivars, Sprint 440 and Dasher II had similar fruit yield, quality rating, and days to harvest. Sprint 440 and Dasher II had the highest yields in terms of total fruit weight, followed by the remaining two slicing checks used in the study ‘Poinsett 76’ and ‘Marketmore 76’ (Table 4).
There were 16 cultigens with a higher number of total fruit than the check cultivar Sprint 440, three cultigens (PI 118279, PI 304805, PI 561145) with a higher total fruit number than Poinsett 76, and five cultigens (PI 118279, PI 304805, PI 561145, PI 234517, PI 512614) with a higher total fruit number than Dasher II. Cultigens with both high fruit weight and number were PI 118279 (Brazil), PI 234517 (USA SC), PI 304805 (USA NY), and PI 512614 (Spain). The four cultigens produced higher total, early, and marketable fruit weight and number than the check cultivars of the same type. Their percentage of cull fruit weight was higher than Sprint 440, but their percentage of cull fruit number was lower. Fruit quality ratings were lower than the check, and PI 234517 had the best fruit quality rating of the four. The four PI accessions had similar days to harvest. However, PI 304805 took 8 d longer than the check (Table 4).
Seven cultigens produced higher early yields (by weight) (PI 234517, PI 118279, PI 368560, PI 173893, PI 165499, PI 512614, and PI 512615) and by fruit number (PI 118279, PI 234517, PI 173893, PI 288996, PI 390259, PI 512614, and PI 561148) than the best check, Dasher II. Forty PI accessions had a higher early yield percentage (by weight) than the best check, Dasher II. Cultigens with the highest early yield percentage (by weight) were PI 338234, PI 368551, PI 368559, PI 173893, PI 368560, PI 379283, PI 250147, PI 357860, PI 561144, PI 267745, and PI 391570. Cultigens with both high early yield and high early yield percentage (by weight) were PI 173893 and PI 288996. Thirteen cultigens had a higher early yield percentage (by number) compared with the highest yielding check Sprint 440. PI 118279 was the only cultigen with a high early fruit yield and high early yield percentage (by weight) compared with the high check (Table 4).
Eighteen cultigens produced higher marketable yields (by weight) while 11 cultigens had a higher marketable yield percentage (by weight) compared with the best performing slicing cucumber check, Poinsett 76. Cultigens with both high marketable yield and higher marketable yield percentage (by weight) compared with the checks were PI 304805, PI 369717, PI 390244, PI 504815, and PI 512598. Five cultigens (PI 504816, PI 401732, PI 304805, PI 432864, and PI 118279) had high marketable yield (by number) compared with the best check, Sprint 440. Eleven cultigens (PI 481616, PI 504816, PI 432864, PI 390244, PI 401732, PI 525075, PI 561146, PI 390260, PI 512633, PI 344347, and PI 512639) had a higher marketable yield percentage (by number) compared with the high check, Poinsett 76. PI 401732, PI 432864, and PI 504816 had both high marketable yield and high marketable yield percentage compared with the best checks (Table 4).
Of the four slicing cultigens used as checks in this study, Marketmore 76 had the lowest culled fruit percentage (by weight) followed by Sprint 440, Poinsett 76, and Dasher II. Two cultigens (PI 338234 and PI 481616) had a lower culled fruit percentage (by weight) than Marketmore 76. The check cultigens with the lowest culled fruit percentage (by number) were Marketmore 76, Sprint 440, Dasher II, and Poinsett 76. Eight cultigens (PI 390238, PI 481614, PI 250147, PI 379280, PI 368560, PI 512625, PI 338234, and PI 481616) had a lower culled fruit percentage (by number) than Marketmore 76 (Table 4).
The four slicing cucumber checks had the highest fruit quality ratings of the four cucumber types. PI 306785 from Canada was the only PI accession that had a similar fruit quality rating compared with the checks. Slicing cultigens that ranked just below the checks for fruit quality were PI 561148, PI 561145, PI 512633, PI 422192, PI 451976, and PI 406473 (Table 4). PI 176519 was the only slicing cultigen that was harvested as early (55 d) as Marketmore 76, the earliest slicing check. The latest cultigen was PI 481616, which took 81 d to harvest (Table 4).
Middle-Eastern (Beit Alpha) Cucumber
WI 2757 was included as a check representing late-maturing, low-yielding, gynoecious inbreds. A total of 229 middle-eastern (Beit Alpha) cultigens produced higher total fruit weight than the check WI 2757, while 32 cultigens produced higher fruit weight than the standard pickling cucumber check, Calypso. The cultigens with the highest total fruit weight were PI 167050, PI 163213, PI 532519, PI 211978, PI 357864, PI 183231, and PI 211117. Nine cultigens had twice the total fruit weight of WI 2757. There were 97 cultigens with a higher fruit number than WI 2757, while 25 cultigens produced higher fruit number than Calypso (Table 5). Cultigens with highest total fruit number were PI 175693, PI 532519, PI 292010, PI 176956, PI 171601, PI 181910, PI 293923, PI 175690, PI 535881, and PI 525152. The cultigens which were ranked in the top 10% for both total fruit number and total fruit weight were PI 137856, PI 169391, PI 171601, PI 175693, PI 181755, PI 292010, PI 525152, PI 532519, PI 534540, PI 534543, and PI 535881 (Table 5).
There were 164 cultigens with higher early yield and higher early yield percentage (by weight) compared with the check WI 2757, while 32 cultigens were higher in early yield compared with the standard pickling check, Calypso. Cultigens with the highest early yield and highest early yield percentage (by weight) were PI 357849, PI 512628, PI 379287, PI 169384, PI 344433, PI 211589, PI 182188, PI 172852, PI 357859, and PI 357834. Of the cultigens with high early yield, 147 had higher early yield (by number) than WI 2757, while 225 had a higher early yield percentage (by number) than WI 2757. PI 172852 was the only cultigen common to both groups (Table 5).
A total of 164 middle-eastern PI accessions had a higher marketable yield (by weight) than the best check. Cultigens in the top 10% category that had >6 Mg ha-1 marketable yield were PI 171601, PI 176924, PI 534543, PI 163213, PI 211117, PI 176951, PI 175693, PI 169380, and PI 344437. There were 72 cultigens with a higher marketable yield percentage (by weight) than the best check. Cultigens with the best performance for marketable yield percentage (by number) were PI 172844, PI 176924, PI 174173, PI 357843, PI 176522, and 176951. PI 171601, PI 176924, PI 176951, and PI 357843 were in the top 10% group for both high marketable weight and high marketable yield percentage (by weight) (Table 5).
There were 87 cultigens with a higher marketable yield (by number) than the check, WI 2757, while 76 cultigens had a high marketable yield percentage (by number). Cultigens in the top category for marketable yield, which also produced >50 000 marketable fruit ha-1, were PI 534543, PI 293923, PI 181910, PI 292010, and PI 171601. Cultigens in the top 10% for marketable yield percentage (by number) were PI 171604, PI 357843, PI 176924, PI 169385, PI 169380, PI 357854, and PI 169383 (Table 5).
There were 214 and 89 cultigens, respectively, having a lower percentage of culls (by weight and number) than the check, WI 2757. The PI accessions that were in the top 10% for lowest percentage of culled fruit (by weight and number) were PI 169385, PI 172852, PI 176924, PI 222243, PI 357843, PI 357849, and PI 512628 (Table 5). There were 30 PI accessions with fruit quality ratings better than the middle-eastern (Beit Alpha) check, WI 2757. Some of the PI accessions with high fruit quality ratings were PI 535881, PI 532519, PI 525153, PI 534539, PI 534541, PI 525154, PI 422197, PI 292010, PI 525155, and PI 525165 (Table 5).
There were 222 PI accessions with earlier yield than WI 2757, which took 64 d to harvest. The earliest middle-eastern (Beit Alpha) cultigen took 52 d to harvest. Some of the other cultigens that took fewer days to harvest were PI 226509, PI 175694, PI 174177, PI 344439, and PI 211975, which all took between 52 and 54 d to harvest. PI 357853 took the longest to produce fruit (77 d) (Table 5).
Trellis Cucumber
Trellis type cultigens with the highest total fruit weight were PI 264228, PI 478366, PI 390262, PI 532524, PI 390267, and PI 532520 (Table 6). Cultigens with high total fruit number were PI 432849, PI 264228, PI 275411, PI 532520, PI 390262, PI 489754, PI 518854, PI 478364, PI 478366, and PI 532523. Eight cultigens (PI 263085, PI 264228, PI 275411, PI 390262, PI 390267, PI 478366, PI 511820, and PI 532520) were in both lists of the top 10% for fruit weight and number. Cultigens of the trellis type that had high early yield (by weight) and high early yield percentage (by weight) were PI 357837, PI 418963, PI 422167, and PI 432889. Cultigens with high early yield and high early yield percentage (by number) were PI 192940, PI 193497, PI 212233, PI 264228, PI 275412, PI 432851, and PI 432889 (Table 6).
Cultigens with the highest yields for marketable fruit weight were PI 478366, PI 264228, PI 532524, PI 518851, PI 390262, PI 390267, PI 422167, PI 275411, PI 419182, and PI 419010 (all greater than 20 Mg ha-1). PI accessions of the trellis type with high marketable yield percentage (by weight) were PI 192940, PI 357841, PI 390263, PI 368554, PI 267742, PI 470254, PI 357837, PI 418963, and PI 193497. PI accessions ranked in the top 10% for marketable fruit weight and marketable yield percentage (by weight) were PI 264228, PI 357837, PI 422167, PI 432889, and PI 518851. PI accessions with high marketable fruit number were PI 264228, PI 275411, PI 511820, PI 518851, PI 390267, and PI 478366 (all greater than 40,000 fruit ha-1). PI 368554 from Yugoslavia had 100% marketable fruit in all replications in all environments of the study. Cultigens that ranked in the top category for both marketable fruit number and marketable yield percentage (by number) were PI 192940, PI 193497, PI 212233, PI 264228, PI 275412, PI 432851, and PI 432889. PI 264228 and PI 432889 were in the top group for marketable fruit (number and weight) and percentage of marketable fruit (number and weight) (Table 6).
PI accessions with the lowest percentage of culls in the trellis type (by weight and number) were PI 192940, PI 212233, PI 255938, PI 357830, PI 368554, and PI 368555 (Table 6). Cultigens with the highest fruit quality ratings among the trellis type cultigens were PI 422184, PI 255935, PI 285608, PI 422167, PI 372893, PI 356833, PI 511821, PI 255933, PI 390262, PI 508460, and PI 275410 (Table 6). The earliest of the trellis cultigens were PI 263081, PI 419183, PI 518854, PI 432849, PI 267742, and PI 275411 (Table 6).
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CONCLUSIONS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSNOTESRESULTS AND DISCUSSIONCONCLUSIONSREFERENCES |
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ACKNOWLEDGMENTS |
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NOTES |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSNOTESRESULTS AND DISCUSSIONCONCLUSIONSREFERENCES |
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Received for publication June 25, 2001.
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