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Lurline Marsh

The effect of moisture content on the emergence and development of `Pinkeye Purple Hull' and MN 13 cowpea [Vigna unguiculata (L.) Walp.] and `Clemson Spineless' okra [Abelmoschus esculentus (L.) Moench] seeds was investigated in a 3-year field study. Moisture content, ranging from 8% to 52%, was obtained by combining seeds, vermiculite, and varying volumes of water in sealed polyethylene packets and incubating them at 22C for 3 days. High moisture promoted the emergence of MN 13, did not significantly affect that of `Pinkeye Purple Hull', and decreased that of `Clemson Spineless' seeds. Percent seed emergence 22 days after planting averaged 17 % for `Clemson Spineless' and 15% for `Pinkeye Purple Hull' seeds, but was 44% for MN 13. High moisture generally promoted early harvest of MN 13 and increased root dry weight but did not affect fresh-pod yield significantly.

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Carlos A. Parera and Daniel J. Cantliffe

Presowing seed treatments were devised to improve emergence and crop uniformity of two sweet corn (Zea mays L.) cultivars [`Crisp N' Sweet 711' (CNS-711) and `How Sweet It Is' (HSII)] that carry shrunken-2 (sh2) mutant endosperm. The treatments included a fungicide combination, sodium hypochlorite (SH), solid matrix priming (SMP), and SMP combined with SH during treatment (SMPSH). Seed germination was tested in a laboratory cold test. Emergence percentage, emergence rate index (ERI), and seedling dry weight were calculated from field trials. CNS-711, in the cold test and field trials, had a higher germination rate, ERI, final emergence, and seedling dry weight than HSII. In both cultivars, SMPSH significantly improved germination in the cold test and final emergence and ERI in the field trials for HSII compared to nontreated seeds. There was no significant difference between the fungicide and SMPSH treatments regardless of cultivar. These results suggest that the combination of SMP and disinfection with SH can be an alternative seed treatment to fungicides to improve uniformity and stand establishment in sh2 sweet corns.

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Ana Morales-Sillero, María Paz Suárez, María Rocío Jiménez, Laura Casanova, José Ordovás and Pilar Rallo

The germination of seeds and the growth of the generated plant are two phases of great importance in an olive breeding program. In this work, three stratification treatments and five cultivars (Hojiblanca, Manzanilla Cacereña, Manzanilla de Sevilla, Toffahi, and Uovo di Piccione) used as female parents in a breeding program for table olive were evaluated along two years to improve germination protocols. The stratification treatments affected seed germination (percent seeds with radicle), radicle length, seedling emergence (percent emerged hypocotyls), and the average time of emergence. The cultivars have shown great variability with respect to the requirements of the seeds and seedling growth performance. None of the treatments with heat application (25 °C) after chill (14 °C) improved the percentage of germinated seeds and seedling emergence in any year compared with the control treatment (30 days at 14 °C). Cultivars such as Manzanilla de Sevilla and Toffahi seem to be a good choice of female progenitors to improve emergence rates and to obtain early vigorous progenies, a character that has been related to a shorter juvenile period of the seedlings. Moreover, in these progenies, a clear lower apical dominance was found from the first stages of seedling growth. The olive fruit and seed traits were also influenced by the female parent. In fact, ‘Hojiblanca’ and ‘Uovo di Piccione’ showed a higher number of empty seed fruits and double seed fruits compared with the other studied cultivars.

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Thomas S.C. Li and Douglas A. Wardle

The influence of seed treatments and planting depth on the percentage of seed emergence of Hippophae rhamnoides L. `Indian-Summer', H. tibetana Schlecht., H. neurocarpa Liu & He, H. salicifolia D. Don, and H. rhamnoides subsp. rhamnoides, sinensis, turkestanica, and mongolica were studied. Surface seeding had higher percentages of seed emergence and more rapid completion of emergence compared to a 1- or 2-cm (0.4- or 0.8-inch) seeding depth. Seeds soaked in water or potassium nitrate solution at room temperature emerged in higher percentages. Average plant height of the eight species and subspecies varied significantly at the end of first growing season.

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Claudinei Andreoli and Anwar A Khan

Emergence and stand establishment of pepper and tomato seeds often are slow and erratic, particularly under stress conditions. Field emergence trials sometimes have not responded to priming in pepper. In this study, we examined the combining effect of matriconditioning with GA4+7 to hasten germination and improve stand establishment of pepper and tomato seeds. The results showed that, in all cases, even under stressful conditions, the combined matriconditioning plus GA treatment was effective in improving germination and emergence of pepper and tomato seeds. Emergence was improved in 20% when seeds were treated with GA4+7 up to 200 mM. Thus, matriconditioning during which germination is suspended, provides a unique means to rapidly and efficiently digest the endosperm by GA-induced enzymes and reduce not only the mechanical restraints but also provide the energy for embryo growth.

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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).

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Michael W. Smith, Becky S. Cheary and Becky L. Carroll

Parameters were defined to germinate pecan [Carya illinoinensis (Wangenh.) C. Koch] seeds in aerated water followed by container planting. Germination was not affected by the ratio of seeds to water in the germination containers. Highest germination rates with the greatest uniformity in germination were obtained with a water bath temperature of 32 °C. Stratification up to 188 days increased the rate of germination, but the largest response was between no stratification and 56 days (6.5 days vs. 2.3 days to reach 50% germination, respectively). Seeds that were germinated in a water bath, then planted in containers, achieved 50% emergence in 4.7 days compared to 12.4 days for direct-planted seed. Emergence was more uniform when seeds were germinated in water before planting compared with seeds that were directly planted in containers (7.0 days vs. 9.5 days between 10% and 90% emergence, respectively). Also, by germinating the seeds before planting, nonviable seeds were eliminated, resulting in 100% emergence compared to 76% emergence when planted directly.

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K.K. Tanino, D.R. Waterer, S.R. Abrams and L.V. Gusta

Seeds of celery, spinach, onion, cress, water cress, iceberg lettuce, Great Lakes lettuce, cabbage, tomato, sweet corn and celery were pre-treated with 0.1 μM/g seed of both ABA and analogs of ABA. The chemicals were dissolved in a mixture of methanol:hexane (9:1/v:v) and applied to the seeds for approximately 3 minutes. The solvent was removed from the seeds within 5 minutes by rotary evaporation under reduced pressure. Effects on petri plate germination and soil emergence were monitored daily at 5, 10 and 15°C. The methanol/hexane solvent alone improved spinach seed emergence at 10°C from 10% to 100% and from 50% to 90% at 15°C in celery. Certain ABA analogs reduced time to 50% emergence in celery by at least 7 days at 15°C. Two ABA analogs synchronized emergence in celery and effect was temperature-dependent. One analog improved seed germination in tomato from 15% to 90% at 10°C. In most cases treatment effects on radicle germination on petri plates was not a good indicator of treatment effects on emergence from a soil based system.

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K.G.V. Davidson, F.D. Moore, E.E. Roos and C.W. Vertucci

Sweet corn with the shrunken-2 (sh2) gene is characterized by poor seed emergence and low seedling vigor. Also, this variety is sensitive to flooded conditions. Our objective was to determine the effects of aeration, during priming treatment, on germination and vigor. Priming consisted of aerating sh2 maize seed during soaking then drying on a lab bench overnight under a fan. Fifty seeds at a time were soaked (25 ± 2C) in 100 ml deionized water. During this time they received either 75% O2: 25% N2, pure N2, pure CO2, or no gas (soak control) for up to 6 hours. The flow rates ranged from 0.35 to 2 standard liters per minute for 75% O2: 25% N2, 0.8 to 2.5 for N2, and 0.5 to 1.3 for CO2. Pressure was held constant at 1 psi. All samples were weighed before soaking, immediately after soaking, and again upon partial drying. Germination was counted after 7 days using the rolled paper towel method (25 ± 1C). Radicle lengths were measured after 72 hours. Oxygen (75%) increased vigor. Also, O2 permitted greater water absorption (P < 0.02). Carbon dioxide and N2 both decreased vigor. Data suggest that aeration conditions (75% O2) during the hydration treatment has beneficial effects.

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M. Arenas, C.S. Vavrina, J.A. Cornell, E.A. Hanlon and G.J. Hochmuth

Sixteen media prepared from peat, coir, vermiculite, or perlite were used to determine the optimum growing media for tomato (Lycopersicum esculentum Mill.) transplants. Medium composition did not affect tomato seed emergence, although seedling emergence was higher in winter (90%) than summer (85%). Greatest transplant root dry weight, stem diameter, and leaf area were achieved in 50% to 75% peat + 25% to 50% vermiculite in summer. In winter, greatest transplant root dry weight, stem diameter, and leaf area were achieved in eight media: 100% peat, 75% peat + 25% vermiculite, 75% peat + 25% perlite, 50% peat + 50% vermiculite, 50% peat + 50% perlite, 25% peat + 50% coir + 25% vermiculite, 50% peat + 25%coir + 25% vermiculite, and 25% peat +25% coir +25% vermiculite +25% perlite. Transplants grown with >50% coir exhibited reduced plant growth compared to peat-grown transplants, a response that may be associated with high N immobilization by microorganisms and high C:N ratio. Despite transplant growth differences during the summer, fruit yields generally were unaffected by transplant media.