Sweet corn (Zea mays L.) cultivars containing the shrunken-2 (sh2) gene have superior kernel quality but often germinate poorly and display poor seedling vigor. The transplanting of sh2 sweet corn was investigated as a method to improve stand establishment and hasten maturity. Three-week-old plants (sh2 cv. Krispy King) were raised in 200-cell polystyrene trays in either plug-trays (PT), float beds (FB), or ebb-and-flood (EF) production systems and compared with direct-seeded (DS) controls for transplant quality, successful establishment, and early harvest. In 1994, when plants were established in early June, PT plants matured 1 week earlier than DS and FB plants, which had similar mean times to harvest. In 1995, when field planting occurred in July, all plants flowered prematurely when only 60 cm tall. In 1996, the experiment was begun in early May, and survival of all transplants was >85% vs. 54% for DS plants. In 1996, transplants matured 10 to 13 days earlier than DS plants, however, >90% of DS plants produced marketable ears vs. 63%, 49%, and 44% of EF, FB, and PT plants, respectively. The DS plants were also taller with better root development than transplants in all years. Transplants produced smaller, lower-quality ears than did DS plants, thus nullifying the benefits of greater plant populations and earlier maturity. The EF system produced high-quality seedlings because of the greater control of water availability during seedling development. In some areas, the increased value of early sh2 sweet corn may be worth the additional cost of transplanting and greater percentage of unmarketable ears.
Gregory E. Welbaum, Jonathan M. Frantz, Malkanthi K. Gunatilaka, and Zhengxing Shen
M. D. McCullough, J. E. Motes, B. A. Kahn, and N. E. Maness
One of the problems associated with machine harvesting of spice peppers (Capsicum annuum L.) is plant lodging. Factorial combinations of four bedding treatments and two N rates were compared for effects on lodging and fruit yield of Chile at Fort Cobb and Bixby, Okla.. and of paprika at Bixby, Okla. Bedding treatments were: 1) no-bed; 2) no-bed with 5 cm of soil hilled to the bases of plants; 3) bedded preplant but bed not maintained throughout the growing season; and 4) bedded preplant and bed maintained throughout the growing season. All plots received preplant N at a low rate (45 kg ha-1). Half the plots also received a topdressing of 45 kg ha“ of N at early fruit set. No significant differences were found among the different bedding treatments for lodging. Bedding treatments one and three led to higher Chile yields at Bixby than treatments two and four. Bedding treatments one and two led to higher paprika yields than treatments three and four. Chiles showed an increase in plant height and width with the higher N rate at both locations. The higher N rate also increased plant dry matter and fruit yield in all three studies. Paprika uprooting force was greater in treatments two and four compared to treatments one and three.
Kenneth E. Conway, John M. Dole, Theresa L. Bosma, and Niels O. Maness
Field seedling emergence of four african marigold (Tagetes erecta) breeding lines, A-975, E-1236, I-822, and `Orange Lady', was examined using three or four spring sowing dates and either osmotic or solid matrix priming. Delayed sowing decreased emergence time. Sowing from middle to late April [average soil temperatures 77.0 to 84.2 °F (25 to 29 °C)] resulted in the highest total emergence percentages. Greater fl ower quantities [4.9 to 5.1 million/acre (12.11 to 12.60 million/ha)] and estimated yield [7.5 to 10.8 tons/acre (16.81 to 24.20 t·ha-1)] indicate mid to late April is the optimum time period for direct sowing unprimed seed in the southern Great Plains. Differences between lines were evident in emergence parameters and fl ower harvest data for each year examined, but results were inconsistent from year to year. However, A-975 and E-1236 produced harvestable fl owers most quickly, about 15 d before I-822, which could result in an additional harvest during a season. Osmotic priming of E-1236 and I-822 seed shortened emergence time, increased emergence uniformity, and increased total emergence percentage at early sowing dates as compared to both solid matrix primed and unprimed seed.
J.D. Mihail and S.M. Alcorn
The establishment of stands from directly sown seed may be a way to reduce the current high costs associated with guayule (Parthenium argentatum Gray) cultivation. These field studies were conducted to examine the combined effects of shade and fungicides on the survival of guayule seedlings established from directly sown seed. Soil in the experimental plot was a loam of pH 7.25. The following fungicides: a) Terraclor Super X, b) Ridomil 5G, c) Ridomil PC llG, d) Tilt 3.6E, e) Terracoat, and f) Vitavax + PCNB were tested alone and in combination with the nonwoven polyester shadecloth, Reemay, to identify treatments enhancing seed germination and seedling establishment. In all cases, seedling emergence in microplots covered with Reemay was significantly higher than in noncovered microplots. Terraclor Super X, Ridomil 5G, and Ridomil PC 1 lG were effective only when used in combination with the shadecloth. The long-term survival of guayule seedlings was strongly affected by severe climatic events. Since Reemay-protected seedlings were larger and more robust, they were more likely to survive the climatic extremes than unprotected seedlings. Two new guayule seedling pathogens were recorded -pythium dissotocum Drechsler and P. paroecandrum Drechsler. Chemical names used: 5-ethoxy-3-(trichloromethyl)-1,2,4-thiadiazole (Terrazole) + pen. tachloronitrobenzene (PCNB); N-(2,6-dimethylphenyl)-N-(methoxyacetyl)-alamine methyl ester Ridomil + PCNB; 7. bromo-5-chloro-quinolin-8-yl-acrylate; Terrazole 5,6-dihydro-2-methyl-l,4 -oxathiin-3-carboxanilide + PCNB.
Gerald B. Odell, Daniel J. Cantliffe, Herbert H. Bryan, and Peter J. Stoffella
Primed, pregerminated, or nontreated `FloraDade' tomato (Lycopersicon esculentum Mill.) seeds in combination with several soil amendments were evaluated in three experiments for stand establishment characteristics and fresh-market fruit yields. Total percent emergence, seedling shoot weight, and marketable fruit yield were not consistently improved by GrowSorb, gel-mix, plug-mix covers, or mixtures with seeds as compared with a control (soil cover). However, rate of emergence was generally faster for plots containing primed or pregerminated seeds with soil amendments than for plots with a soil cover. Primed or pregerminated seeds emerged faster, and had higher total percent emergence and heavier seedling shoot weights than nontreated seeds, but there was little difference in response between primed and pregerminated seeds. Plants from the primed or pregerminated plots produced earlier (first harvest) marketable fruit than did plants from nontreated seed plots in one of three experiments. Priming or pregermination of tomato seeds resulted in a more consistently improved stand establishment than soil amendments.
Dale N. Seale, Daniel J. Cantliffe, and Peter J. Stoffella
Primed, primed + BA, or nontreated lettuce (Lactuca sativa L.) seeds were sown with several soil amendment covers or a sandy soil cover (control) to assess stand establishment in three field experiments. Seeds covered with amendments Growsorb LVM 24/48, Growsorb 6/30, and plug-mix had a higher percent emergence than soil-covered seeds in warm soil. Primed seeds (with or without BA) had a higher percent emergence than nontreated seeds. Emergence was more rapid with plug-mix, LVM 24/48, and LVM 6/30 covers than with the sandy soil control. Primed seeds with or without BA also emerged more rapidly and produced heavier seedling shoots than nontreated seeds. Using primed lettuce seeds combined with specific soil amendments can improve lettuce stand establishment under various field conditions. Chemical name used: 6-benzyladenine (BA).
Eric B. Brennan
vegetables, there are situations in which direct seeding of insectary plants may be useful and more cost effective. For example, direct seeding insectary plants may be appropriate where the vegetable is also direct-seeded and therefore present in the field
Thomas E. Marler and Gil N. Cruz
for subpopulations suffering from heavy A. yasumatsui infestations and subpopulations where the infestation level was moderate. For example, the two Guam subpopulations with the greatest level of direct seed infestations of A. yasumatsui exhibited
Tyler C. Hoskins, Jason D. Lattier, and Ryan N. Contreras
was conducted. Predehisced green, yellow–green, and yellow capsules were collected in summer from a random assortment of lilac parents. Seeds were direct-sown in containers ( Fig. 1B ) and in petri dishes with moistened filter paper ( Fig. 1C ). Only
Kathryn M. Kleitz, Marisa M. Wall, Constance L. Falk, Charles A. Martin, Marta D. Remmenga, and Steven J. Guldan
herbs. The purpose of this study was to compare direct seeding to transplants for plant establishment, and to find the number of marketable harvests and the yield for five herbs: calendula, catnip, lemon balm, stinging nettle, and globemallow. Materials