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Abstract

Harvesting a young planting of asparagus (Asparagus officinalis L.) for 4 or 6 weeks the second year after transplanting 1-year-old crowns, followed by harvesting for 8 or 10 weeks the third year, reduced yields significantly the fourth year. Carbohydrate levels in asparagus storage roots decreased during harvest and continued to decrease after harvest during fern production. Carbohydrate levels increased in storage roots after stalks had matured, and were restored to preharvest levels by mid- to late summer. All treatments possessed comparable levels of storage carbohydrates by the end of the season. Asparagus storage carbohydrates were identified as fructose-oligosaccharides, which varied considerably in size, mobility, and percent fructose and glucose. The largest oligosaccharides were composed of ∼ 90% fructose, ∼ 10% glucose; molecular weights did not exceed 4,000.

Open Access

carbohydrate supply in model callus cultures and shoot tips of asparagus ( Asparagus officinalis L.) Plant Physiol. 158 561 568 10.1078/0176-1617-00312 Kays, S.J. Paull, R.E. 2004 Postharvest biology. Exon Press, Athens, GA King, G.A. Borst, W.M. Stewart, R

Free access

Abstract

Transplants of asparagus (Asparagus officinalis L.) were grown in sand culture under varying ratios of NO3 and NH4. Maximum growth occurred in a nutrient solution with a N ratio of 75% NO3 – N and 25% NH4 – N. Growth was significantly reduced when the N composition was either 100 or 75% NH4 – N. CaCO3 reduced ammonium toxicity but also reduced seedling growth.

Open Access

Abstract

Asparagus aphid [Brachycorynella asparagi (Mordvilko)] feeding without freezing reduced vigor of asparagus (Asparagus officinalis L.), as measured by crown size, fern growth, root necrosis, and bud number, but did not greatly reduce short-term survival. Freezing dormant crowns for 24 hr at −4.5C killed some crowns and reduced vigor of survivors. Aphid feeding and freezing were synergistic; they reduced survival and vigor of survivors to a much greater extent than either aphid feeding or freezing alone. Aphid feeding resulted in early budbreak and precocious growth. A method for counting aphids per plant was developed.

Open Access

Abstract

A computer simulation of asparagus growth is developed and used to evaluate the effects of various harvest strategies on short and long term commercial yield of asparagus (Asparagus officinalis L.). At present asparagus is harvested until the canners stop buying, usually in the 3rd or 4th week of June in southern Michigan, purchase generally being terminated by the reduction of spear diameter (whips), increase in fiber content of the spears or opening of the bracts. The simulation shows that this stragety is economically optimal for any single year; however, if the grower terminates the harvest every year on June 1, then the average yearly yields are significantly greater than those derived from the previous strategy. Skipping strategies, in which the grower skips a harvest every nth year (2nd, 3rd, or 4th), produced significantly lower 15 year average yields than either of the other 2 strageties, but produced significantly greater yields per plant.

Open Access

Abstract

Variations in plant growth, partitioning of dry matter and leaf area in seedling plants of F1 hybrid and open-pollinated Asparagus officinalis L. were measured and related to the yielding ability of the mature plants. The distribution of dry matter differed between hybrid (UC157) and the open-pollinated (OP) (UC72) cultivar. The root biomass was greater in the F1 throughout the experiment. From 2 to 14 weeks after emergence percent dry weight of root per plant ranged from 32 to 54 for the F1 and from 24 to 48% for the OP and percent dry weight of fern per plant ranged from 65 to 42% for the F1 and from 72 to 48% for the OP. Very high positive correlations were found between number of roots and stalks, length of stalk and root length, and “leaf” area and cladophyll dry weight.

Open Access
Authors: and

Abstract

This study was initiated to establish critical N plant tissue levels for asparagus (Asparagus officinalis L.) during the fern growing season. Tissue samples for chemical analysis were taken from asparagus plants over three growing seasons. The experiment consisted of nine treatments with five levels of water ranging from 750 to 4200 mm·ha−1 and five levels of N fertilizer ranging from 100 to 655 kg N/ha. Only the cladophylls were sampled during the fern growing season beginning in mid-April and monthly through mid-September. Total N concentration at various sampling dates and spear yield were highly correlated. Total N concentration indicated the N status of the asparagus plant. Minimum or critical levels of total N were established for the fern growing season in the desert regions of Arizona.

Open Access

Abstract

Asparagus (Asparagus officinalis L.) root tissue and root extracts were used to investigate the previously reported release of toxic chemicals from senescing root tissue. Greenhouse studies showed that the severity of crown or root rot of asparagus seedlings increased in direct proportion to increased amounts of dried root tissue incorporated into soil with either F. oxysporum f. sp. asparagi, F. moniliforme, or a combination of these two pathogens. When excised asparagus roots were treated with increasing concentrations of a water extract of dried asparagus root tissues, electrolyte efflux increased, peroxidase activity decreased linearly, and respiration decreased. Active components in the extracts were heat-stable. Our data suggest allelochemicals of asparagus may have direct physiological and biochemical effects on asparagus plants that predisposes them to fusarium diseases.

Open Access

Abstract

Seed of asparagus (Asparagus officinalis L.) germinated normally after 2 months of constant freezing (-10°C) or chilling (4°) under water-saturated conditions in laboratory germination studies. However, temperatures cycling weekly from chilling to freezing for 2 months reduced germination to less than 50%, and temperatures cycling weekly from warm (21°/16°, day/night) to chilling to freezing for 2 months reduced germination to 0. The stands of asparagus, field-seeded in November and December, were reduced 85% by winterkill in comparison to spring seeding in March and April. Seeding densities from 10 to 40 seed/m did not compensate for stand loss. The greatest contributor to winterkill apparently was seed rot. March seeding increased plant height, but not crown quality or the number of shoots initiated in comparison to conventional April seeding. High seeding densities did not reduce plant growth or crown yields in the spring plantings. Stand establishment was not different between the spring planting dates. Early March seeding at high densities is recommended.

Open Access

Abstract

Donor callus cells for protoplasts were initiated from mature plants of four selected crowns of asparagus (Asparagus officinalis L.) by placing spear slices on solidified Murashige and Skoog salts and vitamins medium (MS) with 3% sucrose + (in mg·liter−1): 1.0 NAA + 1.2 2,4-D + 0.9 BA or 1.0 kinetin + 2.5 2,4-D. Callus derived from these explants was further subcultured on the same medium. Optimum protoplast yields were enzymatically obtained from such calluses 10 to 20 days after subculture. Of the isolated protoplasts 65% to 75% were viable, and when plated in modified Kao and Michayluk medium at 5 × 104 or 105/ml densities, had 6.5% and 7.3% plating efficiencies, respectively. Protoplast isolations had 0.81% to 1.4% cells present that were not observed subsequently to undergo division. Only the cells of protoplasts of ‘Jersey Giant crown No. 8’ divided during 8 weeks to form microcalluses. After transfer and culture for an additional 4 to 5 weeks on solidified MS + (in mg·liter−1): 0.1 NAA + 1.0 kinetin, shoots regenerated at 28% efficiency. Shoots were rooted at 50% efficiency on solidified MS + (in mg·liter−1): 0.3 NAA + 0.7 kinetin + 2.1 ancymidol + 4% sucrose. The rooted plants were readily transferred to the greenhouse. Chemical names used: 1-naphthaleneacetic acid (NAA), 2,4-dichlorophenoxyacetic acid (2,4-D), N-(phenylmethyl)-1H-purin-6-amine (BA), N-(2-furanylmethyl)-1H-purin-6-amine (kinetin), α-cyclopropyl-α-(4-methoxy-phenyl)-5-pyrimidine methanol (ancymidol).

Open Access