Seedcoat Structure and Oxygen-enhanced Environments Affect Germination of Triploid Watermelon

Triploid or seedless watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai] cultivars often have erratic germination and low seedling vigor. The morphology of the seedcoat on two triploid cultivars—Tri X 313 and Tri X Sunrise—was examined by scanning electron microscopy (SEM) to identify structural differences compared to diploid seeds. Triploid seeds incubated with oxygen-enhanced treatments that included nicking, 1% hydrogen peroxide (H2O2), and 40% oxygen were investigated at low and high medium moisture levels. Triploid seed has a thicker seedcoat with a dense endotesta layer and a larger and highly variable air space surrounding the embryonic axis as compared with diploid seed. All cultivars rapidly imbibed water (≈50% of the original weight) during the first hour of imbibition, with a faster increase for triploids than for diploids. High moisture affected germination to a lesser extent in diploid than triploid seeds. Triploid germination under low medium moisture ranged from 96% to 76%, but was severely reduced to <27% under high medium moisture. Triploid seed germination was significantly improved at high moisture by H2O2 and by 40% oxygen. Triploid watermelon seed is very sensitive to submerged conditions, possibly due to a combination of physiological and morphological defects. The rapid imbibition and excess water collected in the seedcoat and air space surrounding the embryo, could reduce oxygen diffusion and impair metabolic pathways leading to normal germination and seedling development.

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Influence of Diploid Pollinizer Frequencies on Triploid Watermelon Quality and Yields

HortTechnology ◽

10.21273/horttech.13.1.0058 ◽

2003 ◽

Vol 13 (1) ◽

pp. 58-61 ◽

Cited By ~ 3

Author(s):

Dena C. Fiacchino ◽

S. Alan Walters

Keyword(s):

Significant Interaction ◽

Citrullus Lanatus ◽

Hollow Heart ◽

Heart Disorder ◽

Soluble Solids ◽

Growing Seasons ◽

Frequency Interaction ◽

Quadratic Response ◽

Seedless Watermelon ◽

Triploid Watermelon

During the 1999 and 2000 growing seasons in Illinois, studies were conducted to determine the influence of two pollinizers (`Crimson Sweet' and `Fiesta') and three pollinizer frequencies (11%, 20%, and 33%) on `Millionaire' seedless watermelon (Citrullus lanatus) quality and yields. More large-sized [>16 lb (7.2 kg)] `Millionaire' watermelons were produced when `Crimson Sweet' was used as the pollinizer compared to `Fiesta', which resulted in `Crimson Sweet' leading to greater marketable and total `Millionaire' yields. Pollinizers responded similarly over the pollinizer frequencies for `Millionaire' watermelon yields as no pollinizer by pollinizer frequency interaction was observed. The 20% and 33% pollinizer frequencies produced similar `Millionaire' yields per acre and both resulted in greater yields compared to the 11% pollinizer frequency. Soluble solids in `Millionaire' fruits were not influenced by pollinizer or pollinizer frequency. However, hollow heart disorder followed a quadratic response with respect to pollinizer frequency with the lowest amount of hollow heart observed at the 33% pollinizer frequency and greatest at the 11% pollinizer frequency. No significant interaction (P ≤ 0.05) was observed for pollinizer by pollinizer frequency for hollow heart disorder in `Millionaire'; although, more hollow heart disorder in `Millionaire' was observed when `Fiesta' was used as the pollinizer.

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Effect on Production and Quality of Intensifying Triploid Watermelon Crops Using ‘Temporary Trellises’ and CPPU for Fruit Development

HortScience ◽

10.21273/hortsci.43.1.149 ◽

2008 ◽

Vol 43 (1) ◽

pp. 149-152

Author(s):

Francisco Javier Núñez ◽

Maria Victoria Huitrón ◽

Manuel Díaz ◽

Fernando Diánez ◽

Francisco Camacho-Ferre

Keyword(s):

Plant Density ◽

Citrullus Lanatus ◽

Quality Parameters ◽

Traditional System ◽

Crop Intensification ◽

Production Techniques ◽

Seedless Watermelon ◽

Triploid Watermelon ◽

Improve Cost

In Spain, the adoption of the triploide ‘Queen of Hearts’ (Citrullus lanatus Thunb.) watermelon cultivar has brought important changes in the production of seedless watermelon thanks to its magnificent acceptance by the market. The experiments on triploid watermelon presented here examined innovative production techniques that would guarantee the productivity and quality of this cultivar in plastic greenhouses and improve cost-effectiveness, serving growers. Crop intensification was tested under a “temporary trellis” management system, increasing plant density from 2500 plants/ha in the traditional or creeping crop system to 10,000 plants/ha. The “temporary trellis” system was combined with fruit set through the localized application of a 150- to 200-mg·L−1 solution of 1-(2-chloro-4-pyridyl)-3-phenylurea (CPPU). The increase of grafted watermelon plant density to 1 plant/m2 gave rise to an increase in early harvest measured as the number of fruits per surface area compared with the traditional system with a density of 0.25 plant/m2. In addition, a process of temporary trellising facilitates choosing female flowers for applying CPPU. The °Brix and pulp firmness quality parameters did not show significant differences between “temporary trellised” and creeping crops.

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Excess Moisture and Seedcoat Nicking Influence Germination of Triploid Watermelon

HortScience ◽

10.21273/hortsci.35.7.1355 ◽

2000 ◽

Vol 35 (7) ◽

pp. 1355-1356 ◽

Cited By ~ 3

Author(s):

S.L. Grange ◽

D.I. Leskovar ◽

L.M. Pike ◽

B.G. Cobb

Keyword(s):

Seed Germination ◽

High Moisture ◽

Highly Sensitive ◽

Water Conditions ◽

Air Space ◽

Excess Moisture ◽

Diploid Cultivar ◽

Triploid Watermelon ◽

Moisture Conditions ◽

Excessive Water

Poor and inconsistent germination is a problem in triploid watermelon. Nicking was shown effective in improving germination in triploid cultivars. In this experiment, we examined the effects of high and low medium moisture, and nicking on diploid and triploid seed germination. Germination for the diploid cultivar was unaffected by any treatment. At high moisture conditions, triploid seed germination was severely reduced to less than 15%, while nicking significantly improved germination up to 40%. However, this increase is still not commercially acceptable. When seed morphological components were measured for each cultivar, triploid seeds had a larger and highly variable air space as compared to the diploid seed. The data confirm that seed germination is not inhibited by the seedcoat alone, but appears to be highly sensitive to excessive water conditions.

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Scarification and Moisture Effects on Triploid Watermelon Seed Germination

HortScience ◽

10.21273/hortsci.35.4.553c ◽

2000 ◽

Vol 35 (4) ◽

pp. 553C-553b

Author(s):

S. Grange ◽

D.I. Leskovar ◽

L. Pike ◽

G. Cobb

Keyword(s):

United States ◽

Hydrogen Peroxide ◽

Seed Germination ◽

Citrullus Lanatus ◽

The United States ◽

Watermelon Seed ◽

Seed Moisture ◽

Moisture Effects ◽

Air Space ◽

Triploid Watermelon

Triploid watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai] consumption is increasing in the United States However, some of the original problems, poor and inconsistent germination, still exist. Seeds of several triploid and diploid watermelon cultivars were subjected to a variety of treatments to improve germination. Control and scarified seeds, by nicking, were incubated at 25 or 30 °C in either 5 or 10 mL H2O or hydrogen peroxide (H2O2). Triploid seed germination was strongly inhibited in all cultivars when seeds were at 10 mL of H2O or H2O2; both nicking and H2O2 increased germination but not equal to rate of the control in 5 mL H2O or H2O2. Germination of diploid cultivars was unaffected by any treatment. Seed morphological measurments indicated that triploid seed has a smaller embryo with a large and highly variable (cv = 105%) air space surrounding the embryonic axis as compared with the diploid seed. These data suggests that triploid watermelon seed germination is not inhibited by the seed coat thickness alone. Seed moisture plays a significant role in germination, emergence, and stand uniformity.

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Flowering Patterns of Pollenizer and Triploid Watermelon Cultivars

HortScience ◽

10.21273/hortsci.49.6.714 ◽

2014 ◽

Vol 49 (6) ◽

pp. 714-721 ◽

Cited By ~ 2

Author(s):

Cecilia E. McGregor ◽

Vickie Waters

Keyword(s):

United States ◽

Fruit Set ◽

Citrullus Lanatus ◽

Staminate Flower ◽

The United States ◽

Specific Production ◽

The Past ◽

Seedless Watermelon ◽

Triploid Watermelon ◽

Fundamental Requirement

The past 10 years has seen a steep increase in production of seedless watermelon (Citrullus lanatus) in the United States. Seedless fruit is produced on triploid plants that require pollination from diploid pollenizers for fruit set. Synchronization of the staminate flowers on the pollenizers with the appearance of pistillate flowers on the triploids is a fundamental requirement for this production system. Previous research suggested that pistillate flowers reach peak production early in the season, but data are only available for a small number of triploid cultivars. We compared the flowering patterns of 29 triploid cultivars and 20 pollenizers, including 10 harvested pollenizers, during the first 6 weeks after transplanting over 2 years. The average number of days from transplanting (DAT) to the first staminate flower was between 5.3 days and 19.1 days in 2012 and 9.7 days and 24.4 days in 2013 for the pollenizers and between 18.7 days and 27.6 days and 22.1 days and 32.7 days for the pistillate triploid flowers in the 2 years, respectively. K-means clustering of the weekly percentage of plants with staminate and pistillate flowers for the different cultivars shows that different triploid and pollenizer cultivars have different flowering patterns and that some combinations have better synchronized flowering than others. Growers should take particular care when choosing pollenizers for early-flowering triploid cultivars. Harvested pollenizers are better suited to late-flowering triploids and growers should choose triploid and pollenizer cultivar combinations with flowering patterns that best satisfy their specific production goals.

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Effect of 2,4-D and CPPU on Triploid Watermelon Production and Quality

HortScience ◽

10.21273/hortsci.42.3.559 ◽

2007 ◽

Vol 42 (3) ◽

pp. 559-564 ◽

Cited By ~ 12

Author(s):

Maria Victoria Huitrón ◽

Manuel Diaz ◽

Fernando Diánez ◽

Francisco Camacho ◽

Antonio Valverde

Keyword(s):

Citrullus Lanatus ◽

Soluble Solids ◽

Dichlorophenoxyacetic Acid ◽

Cucurbita Moschata ◽

Average Production ◽

Pollinating Insects ◽

Seedless Watermelon ◽

Triploid Watermelon ◽

2,4 Dichlorophenoxyacetic Acid

Pollination is one problem with intensive seedless watermelon (Citrullus lanatus Thunb.) production under unfavorable environmental conditions (low solar radiation and temperature) due to the lowered activity of pollinating insects, such as the bee (Apis mellifera L.). An alternative to overcome these problems is the use of plant growth regulators. For this reason, experiments were conducted for 2 years in plastic greenhouses in the fields of Almeria, southwestern Spain, to evaluate the production and quality of ‘Reina de corazones’ triploid watermelon grafted onto RS841 rootstock (Cucurbita maxima × Cucurbita moschata). Two phytoregulators were used for the development of the ovary: 1-(2-chloro-4-pyridyl)-3-phenylurea (CPPU) and 2,4-dichlorophenoxyacetic acid (2,4-D). Concentrations of CPPU evaluated were 50, 100, 150, and 200 mg·L−1. An application of 0.6 mL was applied to each ovary in addition to 4, 6, 8, or 12 mg·L−1 of 2,4-D to the foliar mass at a proportion of 1000 L·ha−1. Results showed that the production and number of fruit obtained with CPPU treatments were similar to what is obtained by using bees for fruit pollination. Maximum production was reached at concentrations of 100–200 mg·L−1. Average production was 32% to 83% higher than results from 2,4-D at 8 mg·L−1. The number of fruit per plant was 33% to 35% higher as well. In the first assay, a positive correlation was also observed between production and CPPU concentration. CPPU treatments had a lower accumulation of sugars than those with 2,4-D; nevertheless, both treatments showed values of commercially acceptable soluble solids.

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Predicting Hollow Heart Incidence in Triploid Watermelon (Citrullus lanatus)

HortScience ◽

10.21273/hortsci15361-20 ◽

2020 ◽

Vol 55 (12) ◽

pp. 1926-1930

Author(s):

Marlee A. Trandel ◽

Penelope Perkins-Veazie ◽

Jonathan Schultheis

Keyword(s):

Logistic Regression ◽

Cultural Practices ◽

Citrullus Lanatus ◽

Hollow Heart ◽

Placental Tissue ◽

Research Station ◽

Screening Process ◽

Flesh Firmness ◽

Seedless Watermelon ◽

Triploid Watermelon

In triploid (seedless) watermelon [Citrullus lanatus var. lanatus (Thunb. Matsum. and Nakai)], hollow heart (HH) is a disorder that is expressed as a crack in the center of the fruit that expands to an open cavity. Although HH incidence and severity is part of a screening process for marketable watermelon fruit during cultigen evaluations, HH incidence is highly variable with growing season, even when the best cultural practices are used. Placental tissue firmness is also measured because firmness is related to the marketability of watermelon and may be related to HH. Genetic and environmental factors can influence watermelon HH development, including plant genetics, pollen amount and viability, pollinator activity, and temperature and rainfall fluctuations. We used seedless watermelon cultigen evaluation data collected over 3 years (2012–14) to determine the relationship between germplasm HH and tissue firmness. Transplanted watermelon representing 30 to 44 cultigens per year were grown at the Central Crops Research Station, Clayton, NC, and interplanted with pollenizers ‘Ace’ and/or ‘SP-6’. Harvested fruit were cut length-wise and rated for HH incidence and severity. Flesh firmness was determined by a handheld penetrometer at five locations in the flesh (stem end, top side, ground spot, blossom end, and heart). A common cultigen subset, consisting of 13 cultigens that were grown in all three experiments, was used for analysis of HH severity and incidence, and placental firmness. The presence of HH was negatively correlated with tissue firmness in both the large multiyear cultigen set (R2 = −0.32; P = 0.0001) and the common cultigen set (R2 = −0.78; P = 0.0001). Cultigens with lower watermelon tissue firmness values had higher HH incidence and severity. By using multiyear cultigen studies and logistic regression, we were able to detect trends for cultigen susceptibility to this highly variable disorder. Using logistic regression, the probability of HH development was highest for ‘Bold Ruler’, ‘Liberty’, and ‘Affirmed’, and lowest for ‘Maxima’ and ‘Captivation’. The identification of cultigens with a tendency for higher or lower rates of HH will be useful for further research of the causes of HH. Measurements of placental flesh firmness may be useful indicators of susceptible cultigens.

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Stand Survival, Establishment, and Yield of a Diploid and a Triploid Watermelon Transplants of Different Ages and Sizes

HortTechnology ◽

10.21273/horttech.9.4.656 ◽

1999 ◽

Vol 9 (4) ◽

pp. 656-660

Author(s):

John R. Duval ◽

D. Scott NeSmith

Keyword(s):

Factorial Design ◽

Cell Size ◽

Significant Interaction ◽

Seedling Survival ◽

Citrullus Lanatus ◽

Vine Growth ◽

Different Ages ◽

Diploid Cultivar ◽

Seedless Watermelon ◽

Triploid Watermelon

Age and cell size can have various effects on subsequent transplant production. The interaction of the two have not been studied in triploid watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai]. Seedless watermelon production is costly due to high seed prices, therefore it is necessary to optimize transplant performance in the field, and it is often thought that triploid watermelons are less hardy than their diploid counterparts. A 3 × 3 factorial design was established for 2 years to determine the effects of cell sizes 1.5, 3.4, and 7.9 inch3 (25, 56, and 130 cm3) and transplant age (4, 6, and 8 weeks) on the triploid watermelon `Genesis'. The diploid cultivar `Ferrari' was also planted for comparison. Seedling survival was affected by transplant age in 1997, and by cell size in 1998. Early main vine growth showed significant interaction between transplant age and cell size, with older transplants grown in the largest cells producing the longest vines. Early yield of 6-week-old transplants of `Genesis' was higher than 4- or 8-week-old transplants in 1997. Eight-week-old transplants of `Ferrari' outperformed younger transplants in 1997 and 1998. Results show that `Genesis' triploid watermelon transplants could be handled similarly to the diploid `Ferrari' without consequence.

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204 Scarification and Moisture Effects on Triploid Watermelon Seed Germination

HortScience ◽

10.21273/hortsci.35.3.426b ◽

2000 ◽

Vol 35 (3) ◽

pp. 426B-426

Author(s):

S. Grange ◽

D.I. Leskovar ◽

L. Pike ◽

G. Cobb

Keyword(s):

Hydrogen Peroxide ◽

Seed Germination ◽

Significant Role ◽

Citrullus Lanatus ◽

Watermelon Seed ◽

Seed Moisture ◽

Moisture Effects ◽

Air Space ◽

Triploid Watermelon ◽

The U.S

Triploid watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai] consumption is increasing in the U.S. However, some of the original problems, poor and inconsistent germination, still exist. Seeds of several triploid and diploid watermelon cultivars were subjected to a variety of treatments to improve germination. Control and scarified seeds, by nicking, were incubated at 25 or 30 °C in either 5 or 10 mL H2O or hydrogen peroxide (H2O2). Triploid seed germination was strongly inhibited in all cultivars when seeds were at 10 mL of the H2O or H2O2; both nicking and H2O2 increased germination, but not equal to rate of the control in 5 mL H2O or H2O2. Germination of diploid cultivars was unaffected by any treatment. Seed morphological measurments indicated that triploid seed has a smaller embryo with a large and highly variable (CV = 105%) air space surrounding the embryonic axis as compared with the diploid seed. These data suggests that triploid watermelon seed germination is not inhibited by the seedcoat thickness alone. Seed moisture plays a significant role in germination, emergence, and stand uniformity.

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PENGARUH ANTHESIS JANTAN DAN WAKTU POLINASI TERHADAP TINGKAT KEBERHASILAN PEMBENTUKAN BENIH SEMANGKA TANPA BIJI (Citrullus Lanatus Thunberg.)

JURNAL BIOINDUSTRI ◽

10.31326/jbio.v2i1.484 ◽

2019 ◽

Vol 2 (1) ◽

pp. 364-373

Author(s):

Ahmad Ihwanudin ◽

Sri Hartatik ◽

Kacung Hariyono ◽

Josi Ali Arifandi

Keyword(s):

Success Rate ◽

Significant Interaction ◽

Citrullus Lanatus ◽

Pollen Viability ◽

Block Design ◽

The Other ◽

Seed Formation ◽

Randomized Block Design ◽

Seedless Watermelon ◽

Triploid Watermelon

Triploid watermelon seeds are produced from the crossing between watermelon diploid as males and tetraploid watermelons as females. The success of triploid seed formation is influenced by the success of pollination determined by pollen viability which is characterized by the period of anthesis and peptic receptivity by the time of pollination. This experiment was conducted in Jember on 2018. The Factorial Randomized Block Design, 3x3 with three replications, was concucted to determine the effect of male anthesis period and pollination time on the success rate of seedless watermelon seed formation. The results showed that no significant interaction of the male anthesis period and the time of pollination effect. Pollens harvested during pre anthesis give the best pollination results. On the other hand, the best pollination can be done at 07.30 – 08.30 am Keywords: anthesis, pollination, seeds, seedless watermelon.

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