Abstract
Asparagus (Asparagus officinalis L.) root filtrate (RF) depressed asparagus seedling emergence in a sterile peat–vermiculite medium. In a medium inoculated with Fusarium oxysporum f. sp. asparagi (FO), the effect was magnified. The response to RF dose, regardless of level of FO infestation, was quadratic. Comparisons with a sucrose solution of the same percentage of soluble solids as the RF suggested that reduced emergence may have been due in part to enhancement of FO growth by the energy source added to the medium. However, after germinating seeds in RF until radicle emergence, then rinsing and transferring them to FO-inoculated medium, emergence was reduced relative to controls. Therefore, depression of emergence apparently related both to an autotoxin somehow predisposing young radicles and/or hypocotyls to increased FO infection and to stimulation of FO in the rhizosphere by the soluble solids content of the root exudate. Infection was confirmed to be the only role of FO: sterilization of the spore suspension by Millipore (0.2 µm) filtration eliminated pathogen toxicity.
Abstract
Growth studies of field-seeded hybrid and open-pollinated asparagus (Asparagus officinalis L.) were conducted to determine the differences in shoot, bud, and crown growth during the first season after seeding and to determine growth relationships between shoot and crown variables that indicate critical periods of bud and crown production. F1 hybrid (UC 157) and UC800 open-pollinated (OP) asparagus seedlings emerged 4 to 6 weeks after seeding. A lag phase of shoot and root growth lasted 4 to 5 weeks after emergence in both cultivars. UC157 initiated more roots and accumulated more fern and crown fresh weight than UC800 early in the season, but by harvest crowns were not different in root and bud number, fresh weight, or fructose content (crown quality). Root/shoot ratios increased from a 2:1 ratio 6 weeks after emergence to 8:1 (UC157) and 6:1 (UC800) 23 weeks after emergence. Shoot/bud ratios stabilized from an approximate 2:1 ratio initially to an approximate 1:2 ratio 18 weeks after emergence. Bud production in the F1 and OP cultivars increased 6 and 10 weeks after emergence, respectively, and continued unabated up to crown harvest 23 weeks after emergence. Shoot number and fresh weight were not correlated highly with bud number. The number of roots vs. buds and the crown vs. fern fresh weights were correlated highly and were the best indicators of quality crown production. Vigorous fern development throughout the growing season increased the potential to produce higher-quality large crowns.
Abstract
Aqueous extracts of asparagus (Asparagus officinalis L.) roots inhibited seed germination in tomato and lettuce, but not in cucumber. The extracts reduced hypocotyl growth in lettuce, shoot growth in asparagus, and inhibited radicle elongation in barley, lettuce, and asparagus. Seedling growth in tomato and two cultivars of wheat were not affected. Inhibition was concentration-dependent. Radicle growth in ‘Grand Rapids’ lettuce was sensitive to an extract concentration as low as 0.05 g dry root tissue/100 ml H2O. Asparagus radicles were more sensitive than asparagus shoots. In one experiment, phytotoxicity of crude extract was not altered by autoclaving. Aqueous root extracts of A. racemosis Willd. also inhibited germination and radicle growth in ‘Grand Rapids’ lettuce. A crude extract was purified by solvent partitioning, and charcoal adsorption, cation exchange, and thin-layer chromatography (TLC). A band from the TLC was found to fluoresce under ultraviolet light, react with phenolic-sensitive localization reagents, and inhibit the growth of lettuce and asparagus radicles.
Abstract
The effect of salinity on germination, first-year growth, and spear and fern yield of asparagus (Asparagus officinalis L.) was determined in germination dishes, crocks, and field plots, respectively. Saline treatments were imposed by irrigating with water that contained equal weights of NaCl and CaCl2. Spear yield was reduced 2.0% for each unit increase in salinity above 4.1 d S · m−1. Yield reduction was attributed primarily to a reduction in individual spear weight. Mature asparagus plants would be considered the most salt-tolerant crop commercially available. Asparagus possessed nearly the same salt tolerance for germination and spear production with soil salinities <7.2 d S·m−1. Above 7.2 dS·m−1, germination was less salt-tolerant. First-year growth was significantly more salt-sensitive than growth in subsequent years.
-shock treatments were formulated that would be optimal for the apical portion without damaging the lower portion of the spear. Materials and Methods Plant material. Asparagus ( Asparagus officinalis L., cv. UC157) spears were obtained from commercial growers in
Abstract
Single applications of ancymidol at 0.03, 0.12, 0.50, or 1.0 mg/plant were soil applied to asparagus seedlings (Asparagus officinalis L.) 3.5, 5.5, or 7.5 weeks after seeding. Increasing ancymidol rates from 0.03 to 1.0 mg/plant decreased bud number, fern dry weight, but not shoot number at all application times. When ancymidol was applied at 1.0 mg/plant at 3.5 weeks it reduced fleshy root production, but in plants treated at 5.5 to 7.5 weeks, it did not reduce fleshy root production. Increasing ancymidol rates from 0.03 to 1.0 mg/plant reduced the crown dry weight of plants 5.5 weeks and younger. Ancymidol from 0.03 to 1.0 mg/plant applied to 3.5-week-old plants increased the partitioning of dry matter into fern rather than crowns, but delaying application to 7.5 weeks after seeding reversed this relationship suggesting increased carbohydrate storage. Application of ancymidol from 0.03 to 1.0 mg/plant to plants 5.5-weeks-old or younger was considered detrimental to plant growth. Ancymidol at 0.50 mg/plant or less applied to 7.5-week-old plants enhanced the production of a stocky, compact transplant. Chemicals used. Ancymidol: α-cycloprophyl-α-(4-methoxyphenyl)-5-pyrimidinemethanol.
Abstract
In 3 separate experiments, the effects of container types, transplant age, and growing media on asparagus (Asparagus officinalis L.) transplant quality were determined. These transplants then were field planted to determine the effects of propagation methods on plant growth after one growing season. Transplants grown for 10 weeks in deep peat pots (10 cm deep, 177 cm3, and 364 plants/m2) produced crowns and fern of higher fresh and dry weight than other containers (ranging in depth from 5.5 to 7.6 cm, in volume from 53 to 186 cm3, and plant density/m2 from 277 to 1624). Shoot and root growth of 7-, 8.5-, and 10-week-old transplants (grown in identical containers) were similar, but crown fresh and dry weight were reduced for 6-week-old transplants. Ten-week-old transplants originally broadcast-seeded in flats of 1 vermiculite: 1 peat medium (v:v) produced more roots, buds, shoots and fern and crowns of greater fresh and dry weight than those grown in 1 peat : 1 perlite or 1 perlite : 1 vermiculite media. At the end of the growing season, plants originally grown in deep peat pots were superior in number of shoots and fleshy roots, and crown and fern dry weight to those grown in other container types, to transplants of various ages, and to bareroot transplants.
Abstract
Asparagus officinalis L. plants infected with either asparagus virus 1 or asparagus virus 2 exhibited mild reduction of vigor and productivity. Plants infected with both viruses showed severe decline and mortality in the second year in the field.
Abstract
Numerous asparagus (Asparagus officinalis L.) hybrids have been developed worldwide during the past 20 years. Most are clonal hybrids. The French (INRA) breeding program has successively introduced double, clonal, three-way all-male, and F1 (mixed or all-male) hybrids. Because these hybrids are evaluated at different locations during different years, a composite comparison of all cultivars is not feasible. A ranking index has been developed to make useful the huge volume of heterogeneous data that has been accumulated from the many trials during the past 10 years. This index is based for each hybrid on 2 years of comparative harvest data at four locations from about 40 hybrids and check cultivars at each location and each year. Using these rank indexes, the different types of hybrids can be compared one with another and with foreign hybrids. These indexes show that 1) all-male F1 and three-way hybrids tend to have high total yield and earliness; 2) F1 mixed hybrids are likely to have relatively large spear diameter; 3) double, clonal, and foreign hybrids produce the most attractive spears; 4) the general superiority of all-male hybrids is confirmed; 5) the four characters that are the major breeding objectives—early yield, high total yield, large spear size, and attractive spear appearance—are difficult, but not impossible, to combine into one hybrid. The indexes also show that, in spite of general trends, individual hybrids outstanding in all characteristics can be found in each type of hybrid.
Abstract
Series of greenhouse experiments were made to determine the effects of different endomycorrhizal fungi on the growth of oat (Avena sativa L., cv. Alma), strawberry (Fragaria × ananassa, cv. Redcoat), leek (Allium porrum L., cv. American Flag), apple (Malus domestica Borkh., cv. Beautiful Arcade), and asparagus (Asparagus officinalis L., cv. Mary Washington) plants which were grown in a calcined montomorillonite clay (Turface) medium and fertilized with a Long Ashton nutrient solution at 100 ml/week·pot (20 cm diameter). Plants were inoculated with 1 g of fresh ash (Fraxinus americana L.) roots harboring the different fungi. Out of 6 endomycorrhizal inocula used, 4 were well-identified: Gigaspora calospora (Nicol. & Gerd.) Gerd & Trappe, Glomus epigaeus Daniels & Trappe, Glomus macrocarpus Tul. & Tul., var. macrocarpus, and Glomus monosporus Gerd. & Trappe. The results indicate that Turface is a good growing medium for this type of study, as it permits good plant growth and abundant mycorrhiza formation with standard growing conditions. The fungi used produced different effects according to plant host. There was no correlation between the percentage of root infection and the stimulation of growth in the case of strawberry. Contrarily, there was a significant correlation (1% level) in the case of apple, asparagus, leek, and oats plants. No fungal specificity of the endophyte for the host plant was observed. The unknown endomycorrhizal species had effects on plant growth comparable to those of Glomus epigaeus with apple and strawberry plants.