The physiological mechanisms leading to a decline in sprout-vigor, root growth potential and apical dominance during long-term aging of potato seed tubers are currently under investigation. Malondialdehyde (MDA) and ethane, products of peroxidative degradation of PUFA increase in seed-tuber tissues with advancing age (from 2 to 32 months of storage). MDA is known to react with free amino acids to produce lipofuscin-like fluorescent compounds (FC), which build-up in aging/senescent tissues of plants and animals. With advancing seed-tuber age, an increase in free amino acids, MDA and FC concentrations was evident. Moreover, high levels of MDA have been shown to reduce protein synthesis in both plant and animal cells. We therefore examined the extent to which seed-tuber age affects protein synthesizing capacity of tuber tissues during sprouting. Tissue disks from 6- and 18-mo-old seed-tubers at various stages of sprouting, were compared for their protein synthesizing ability by monitoring the incorporation of radiolabelled amino acids into TCA precipitable products. The rate of incorporation (dpm mg protein-1 min-1) was 1.8 to 5.4-fold higher in tissue from 6-mo-old, as compared to that from 18-mo-old seed tubers, at similar stages of sprout development. Loss in protein synthesizing ability (possibly due to direct peroxidative damage) may be an important factor contributing to loss of sprout-vigor from aged potato seed-tubers.
G.N.M Kumar and N.R. Knowles
S. B. Sterrett, C. P. Savage Jr., and K. M. McManus
Studies were conducted in 1988 and 1989 to evaluate the influence of planting time and method on plant establishment and yield of fall broccoli. In 1988, plant establishment of direct-seeded broccoli was not improved with application of vermiculite (63 kg/ha). a cross-linked polyacrylamide polymer (17 kg/ha), or both as anti-crustants over the untreated check (37.6%, 32.2%, 24.6%, and 31% of target population, respectively). In 1989, transplants were compared with double-seeding (planting two seeds 25 mm apart). With seed. germination of 55% in the early planting (8 Aug.). plant populations of double-seeding and transplants were similar, but 42% germination of double-seeding in the late planting (28 Aug.) resulted in lower plant populations than from transplants. While yield reflected differences in plant populations, the percentage of marketable heads from transplants was significantly greater (90.6%) than from seedlings (78.9%). These data suggest that broccoli transplants are a viable option when high soil temperatures may be detrimental to seed germination.
Erin Silva, Mark Renz, and Stephanie Walker
Chile pepper (Capsicum annum) production in the southwest can be impacted by many factors. In particular, factors that alter root growth and development can be critical to pepper productivity. Several factors can cause less-than-optimal taproot formation, including irrigation practices, planting method (seeds vs. transplants), climactic conditions, and competition from weed species for limiting resources. The goals of this research were to quantify the root development of chile peppers established from either seeds or transplants under furrow and drip irrigation. Research was conducted in 2005 at Artesia Plant Science Research Center in Artesia, N.M., using a state-of-the-art drip irrigation system. Differences in root development between both irrigation types and planting methods were measured using of the mini-rhizotron image capturing system. Measurements occurred at a weekly basis to document location, root length density, and pattern of root formation. At the time of harvest, yield and fruit quality were evaluated. Direct-seeded chile plants yielded more fruits than transplanted chile under both irrigation regimes. Patterns of root development differed over time for direct-seeded vs. transplanted and furrow vs. drip-irrigated chile peppers. Planting and irrigation method affected root growth differently at various points in the season. These data can aid in the optimization of management strategies for specific production practices.
Robert F. Bevacqua and Dawn M. VanLeeuwen
Chile pepper (Capsicum annuum L.) yields are highly variable and are strongly influenced by disease and weather. The goal of two field experiments was to evaluate crop management factors, especially planting date, that could contribute to improved and more consistent crop production. Current practice in New Mexico is to direct seed the crop from 13 to 27 Mar. In the first experiment, chile pepper was direct seeded on three planting dates, 13, 20, and 27 Mar. 2000, without or with a fungicide treatment of pentachloronitrobenzene and mefenoxam for the control of damping off. The results indicate planting date had no effect on stand establishment or yield. Fungicide treatment, significantly reduced stand, but had no effect on yield. In the second experiment, chile pepper was direct seeded on six planting dates, 13, 20, 27 Mar. and 3, 10, 17, Apr. 2001, with or without an application of phosphorus fertilizer, P at 29.4 kg·ha-1, banded beneath the seed row. During the growing season, this experimental planting suffered, as did commercial plantings in New Mexico, from high mortality and stunting due to beet curly top virus, a disease transmitted by the beet leafhopper. The results indicate planting date had a significant effect on crop performance. The best stand establishment and highest yield were associated with the earliest planting date, 13 Mar. This date also resulted in the least viral disease damage. Phosphorus fertilizer had no effect on stand establishment or yield. Chemical names used: pentachloronitrobenzene (PCNB); (R)-2-[(2,6-dimethylphenyl)-methoxyacetylamino]-propionic acid methyl ester (mefenoxam).
Michael E. Bartolo and Frank C. Schweissing
Colorado-grown watermelons command a premium price on the market based on their sweetness and overall flavor. Unfortunately, melon production is limited to mid-August through early September. This study was conducted to determine whether intensive production methods could enhance the traditional marketing period. The effects of different combinations of establishment methods, mulches, and rowcovers on `Arriba' (Hollar Seeds) watermelon growth and productivity were investigated in a field trial at the Arkansas Valley Research Center in Rocky Ford, Colo. In 1997, the combinations of transplanting, clear plastic mulch, and perforated or slitted rowcovers produced the earliest harvest and highest yield and fruit weight. The first harvest of the earliest treatments occurred on 4 July. Direct-seeding through clear plastic mulch, both with and without rowcovers, also enhanced earliness relative to the traditional marketing period. However, compared to transplanting, yield and fruit weight were less if the crop was direct-seeded. Intensive plasticulture techniques could substantially increase the earliness of Colorado-grown watermelons. The increased cost of production would be easily off-set by higher productivity and early season prices
Charles L. Webber III and James W. Shrefler
Although CGM has been identified as an organic herbicide for weed control in turf and established vegetable plants, direct contact with vegetable seeds can decrease crop seedling development and plant survival by inhibiting root and shoot development. The objective of this research was to determine the impact of banded corn gluten meal applications on squash plant survival and yields. This factorial field study was conducted during Summer 2005 on 81-cm-wide raised beds at Lane, Okla., with two application configurations (banded and solid), two CGM formulations (powdered and granulated), two incorporation treatments (incorporated and nonincorporated), and three application rates (250, 500, and 750 g·m–2). The two CGM formulations at three application rates were uniformly applied in both banded and solid patterns on 19 Aug. The banded application created a 7.6-cm wide CGM-free planting zone in the middle of the raised bed. The CGM applications were then either incorporated into the top 2.5 to 5.0 cm of the soil surface with a rolling cultivator or left undisturbed on the soil surface. `Lemondrop' summer squash (Cucurbita pepo L.) was then direct-seeded into the center of the raised beds. When averaged across the other factors, there was no significant difference between powdered and granulated CGM formulations or incorporating and nonincorporating the CGM for either squash plant survival or yields. As the CGM application rates increased the plant survival and yields decreased. Banded application resulted in significantly greater crop safety (90% plant survival) and yields (445 cartons/ha) than the broadcast (solid) applications (45% plant survival and 314 cartons/ha). The research demonstrated the potential usefulness of CGM in direct-seeded squash production, if used in banded application configuration.
E. Carvajel-Millan, A.A. Gardea, V. Guerrero-P, F. Goycoolea, and C. Rivera
Apple embryos from moist seeds kept at 4 °C were used for a calorimetric characterization of Red and Golden Delicious apple seed dormancy. Seeds were sampled at 100-h intervals during 1200 h. The metabolic response of such samples was compared to that from chilled Golden Delicious seeds (>1200 h) stored under controlled atmosphere (CA). Isothermal calorimetry at 25 °C, evaluated metabolic activity (q), respiration rate (RCO2), metabolic 65 °C estimated activation energy (Ea) in a 10 to 20 °C range, and respiration coefficients (Q10) from 10 to 50 °C at 10 °C intervals. Data showed a direct relationship between chilling exposure and embryo metabolic responses from both cultivars. Once chilling requirement was satisfied, Red and Golden Delicious seeds presented a significant increase (P ≤ 0.05) in q, 0.94 and 0.98 μW/mg dry weight (dw); RCO2, 9.9 and 7.6 mmol CO2/mg dw; and RSG·ΔHB, 3.6 and 2.5 μW/mg dw, respectively. On the other hand, q/RCO2 did not follow a definite pattern, neither in Red nor Golden Delicious cultivars. Ea decreased 19.2 and 23.4 J/mol per °K per mg dw in Red and Golden Delicious, respectively, as a function of seed chilling. Q10 showed a significant response to temperature, but not to chilling exposure. Golden Delcious seeds from CA showed a significant reduction on q, RCO2, and RSG·ΔHB of 0.28 μW/mg dw, 2.47 mmol CO2/mg dw, and 14 μW/mg dw, respectively. Results show that calorimetry is a sufficiently sensitive, fast, and precise tool to quantify metabolic responses during seed chilling, as evolving energy.
M. Ali Harivandi, William L. Hagan, M. Zak Mousli, and Lin Wu
Stand establishment of direct-seeded hard fescue (Festuca longifolia) is slow. Sodding could speed establishment in landscape plantings. This study looked at the effects of two sod thicknesses and different rates of nitrogen fertilization before and after sodding, on stand establishment and overall turf quality. Evaluations 2, 4 and 8 weeks after sodding assessed rooting and overall turf quality. Thicker sod showed better rooting 4 weeks after planting; after 8 weeks, rooting of both thicknesses was similar. Nitrogen fertilization before or after sodding did not affect rooting. More nitrogen led to better overall turf quality up to 4 weeks after planting; however, this quality difference disappeared 8 weeks after sodding.
Carl E. Motsenbocker, J. Blair Buckley, William A. Mulkey, and James E. Boudreaux
Field studies were conducted in 1991 with `Jalapeno-M' and `TAM' Jalapeno pepper. Plants were established by direct seeding at 10, 20, 30, and 40 cm in-row plant spacing. Lodged plants, fruit quality and yield were monitored. A commercial snap-bean harvester was evaluated for harvest. Closer plant spacings resulted in greater yields and reduced plant lodging. No interaction of variety with plant spacing was observed. There were, however, differences in several yield parameters due to variety. Fruit quality characteristics of mechanically and hand harvested pepper stored at 6 C were similar. The use of the mechanical snap-bean harvester appears to be a feasible technique to harvest Jalapeno pepper.
Paul W. Bosland
Chile pepper (Capsicum spp.) hybrids are normally produced by hand-emasculating the female parent and then pollinating the emasculated flower by hand. Increased yield has occurred with F1 hybrid seed, but the seed is considered too expensive by growers to be direct-seeded, a common production practice in the southwestern U.S. chile pepper industry. In ornamental flowers, when F2 hybrid seed is available, it is cheaper than F1 hybrid seed. If F2 hybrid chile pepper cultivars could manifest heterosis, and produce fruit quality acceptable to the chile pepper industry, then a less-costly alternative would be available to growers. A series of field trials with jalapeños was conducted to test F1 hybrid cultivars to their F2 progeny for yield and fruit quality. The results indicated that in some instances the F2 progeny can yield as well as the F1 hybrid parent. Therefore, F2 hybrid cultivars can be used in a commercial production system. However, if a male-sterility system is used to produce the F1 hybrid cultivar, the F2 progeny will have significantly lower yield than the F1 hybrid parent, as was the case in one accession in this trial. Nevertheless, F2 hybrid cultivars are an additional way to supply high yielding hybrid cultivars to growers.