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- Author or Editor: John Duval x
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.
During 1998 and 1999, `Genesis' triploid watermelons were grown in large blocks with a single row of the diploid `Ferarri' planted as a pollinizer in the middle. A once-over harvest of triploid watermelons was made each year in harvest lanes 0-, 1.5-, 3.0-, 4.5-, 6.0-, 7.5-, and 9.0-m perpendicular distances from the pollinizer row. Individual fruit were weighed and counted. Data from both years indicated a similar distribution of triploid fruit with respect to distance from the pollinizer row. The greatest number of triploid fruit per unit land area was in the harvest row 3.0 m from the pollinizer row. When distance from the pollinizer row was 6.0 m or greater, triploid fruit numbers diminished substantially. Yield estimations made each year using the fruit density data suggested that a 1 pollinizer: 4 triploid ratio gave the maximum total triploid fruit yield per hectare for 1.5-m row spacings. These results should prove useful in designing field planting strategies that seek to optimize triploid watermelon production.
Visualizing the effect of irrigation volume on water movement in and below the root zone of strawberry (Fragaria ×ananassa) plants may be used to determine when to split irrigation. By injecting blue dye (Terramark SPI High Concentrate) during controlled irrigation events with several drip tapes commonly used by area growers, the objectives of this project were to: (1) determine vertical, lateral and longitudinal movements of wetted zones applied by drip irrigation on a Seffner fine sand soil; (2) describe the shape of the wetted zone for increasing irrigation volumes; and (3) determine the irrigation after which water moves below the root zone. Dye tests consisted in preparing mulched beds with different drip tapes (7 total), injecting dye, irrigating with the selected volume of water (V), digging longitudinal and transverse sections of the raised beds, and taking measurements of vertical (depth; D), lateral (width; W) and longitudinal (L) water movement. Increasing V from 279 to 3353 L/100 m, significantly increased D, W and L. Depth and W responses to V were D = 0.19 V + 26.1 (R 2 = 0.80), and W = 0.36 V + 13.5 (R 2 = 0.78). Emitter-to-emitter coverage occurred after 4 hours for 30-cm spacing. Based on expected root depths of 20 cm when the strawberry plants are young and 30 cm when they are fully grown, largest V before water moved below the root zone were 325 and 870 L/100 m, which corresponds to typical irrigation times of 1 and 3 hours, respectively. Greater irrigation volumes may reduce water use efficiency and increase the risk of nutrient leaching below the root zone.
During 1998 and 1999, `Genesis' triploid watermelons [Citrullus lanatus (Thunb.) Matsum. & Nak.] were grown in large blocks with a single row of the diploid `Ferarri' planted as a pollinizer in the middle. A once-over harvest each year was made in harvest lanes 0, 1.5, 3.0, 4.5, 6.0, 7.5, and 9.0 m perpendicular distances from the pollinizer row. Individual fruit were weighed and counted. Data from both years indicated a similar distribution of triploid fruit with respect to distance from the pollinizer row. The greatest number of triploid fruit per unit land area was in the harvest row 3.0 m from the pollinizer row. When distance from the pollinizer row was 6.0 m or greater, triploid fruit numbers diminished substantially. Yield estimates made each year using the fruit density data suggested that a 1 pollinizer: 4 triploid ratio gave the maximum total triploid fruit yield per hectare for 1.5-m row spacings. These results should prove useful in designing field planting strategies to optimize triploid watermelon production.
Production of triploid watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai] transplants is hindered by low and nonuniform emergence, and seedcoat adherence. Seedcoat adherence leads to weakened and slow-growing plants. High seed costs are prohibitive to many transplant growers. Improvement of emergence would lower financial risks to growers and transplant producers. Mechanical scarification was examined as a means to decrease the impact of both problems. Seeds of `Genesis' triploid watermelon were placed in a cylinder with 100 g of very coarse sand and rotated for 6, 12, 24, and 48 hours at 60 rpm. Nontreated seeds were used as a control. Data were taken daily on emergence and seedcoat adherence. The experiment was repeated at three temperature regimes. No significant differences were observed in seedcoat adherence. Scarification, however, did significantly improve emergence under test conditions.
Seeds of triploid watermelons [Citrullus lanatus (Thunb.) Matsum & Nakai] often germinate poorly, which prevents adequate stand establishment in both field and greenhouse environments. Methods of improving germination and emergence of these expensive seeds would reduce overall risk to growers, thus increasing the crop's market prominence. Seeds of `Genesis' triploid watermelon were subjected to three treatments: 1) seedcoat removal; 2) clipping the seedcoat opposite the radicle end; or 3) no seedcoat alteration; and were germinated on agar in the presence of a 0%, 1%, 2%, 4%, or 8% aqueous H2O2 at constant 28 °C in the dark. Seedcoat removal, clipping, and all levels of H2O2 increased final germination percentages relative to the control (no seedcoat alteration, no H2O2) by as much as 70%. Hydrogen peroxide levels >2% resulted in severe injury to germinating seeds. These findings suggest that germination barriers of triploid watermelon are seedcoat related, and that seedcoat alteration and H2O2 can overcome these barriers.
Production of triploid watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai] transplants is hindered by poor, inconsistent emergence, and frequent seed coat adherence to cotyledons. Seed coat adherence leads to weakened and slow growing plants. High seed costs, coupled with stand establishment problems, discourages transplant producers from growing this crop. Improvement of triploid watermelon emergence will lessen financial risks to growers and transplant producers and will provide a more reliable production system. Mechanical scarification was evaluated as a means to overcome inconsistent emergence and seed coat adherence. Seeds of `Genesis' triploid watermelon were placed in a cylinder with 100 g of very coarse sand (1.0 to 2.0 mm diameter) and rotated at 60 rpm for 0, 6, 12, 24, and 48 hours in a series of experiments. Number of emerged seed was recorded daily, to obtain emergence dynamics. No significant differences were observed in seed coat adherence among treatments. The longest duration of scarification However, enhanced emergence as compared to the control in three of four experiments. These data support earlier suggestions that a thick or hard seed coat is a factor contributing to poor germination and emergence of triploid watermelons.
Transplants for both vegetable and floral crops are produced in a number of various sized containers or cells. Varying container size alters the rooting volume of the plants, which can greatly affect plant growth. Container size is important to transplant producers as they seek to optimize production space. Transplant consumers are interested in container size as it relates to optimum post-transplant performance. The following is a comprehensive review of literature on container size, root restriction, and plant growth, along with suggestions for future research and concern.