model identification Inst. Electrical Electronics Eng. Trans. Automatic Control 19 716 723 Boydston, R.A. 1995 Effect of tillage level and herbicides on weed control and yield of asparagus ( Asparagus officinalis ) in the Pacific Northwest Weed Technol
Yield, spear weight, and spear number of Asparagus officinalis L. were either unaffected or increased at 2 locations in subsequent years when plants were first harvested 1 year after planting crowns as compared to plants first harvested 2 years after planting crowns.
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.
The motherstalk method of `Jersey Centennial' asparagus production was examined in two greenhouse studies. This technique allowed for one, two, or three spears to develop a mature fern while permitting harvest of later-developing spears. Cumulative yield was highest 10 weeks after planting with one and two motherstalks, and crown dry weights in these treatments were similar to those of the nonharvested treatment. In a second experiment, spear yield and crown dry weight were determined when the motherstalk was initiated at 0, 2.5, and 5 weeks after planting. Yields were highest when the motherstalk was established at week 0 or 2.5 compared to week 5. Crown dry weights of early motherstalk treatments were similar to those of the nonharvested treatment at the end of the 10-week harvest period. Our results indicate that the motherstalk system may allow for extended asparagus harvest in temperate areas.
RAPD (Random Amplified Polymorphic DNA) is being utilized to construct a molecular genetic linkage map. The mapping population used is comprised of 65 individuals. Of the 240 decamer primers (Operon) tested to date, 50 polymorphic bands have been resolved. The 50 markers are divided into two groups according to the genotypes of the two parents. The first group is where the female parent is heterozygous and male parent is homozygous and it has 17 markers, while the second group, in which male parent is heterozygous and female parent is homozygous, has 33 markers. Analysis of the two groups by MAPMAKER indicated that two linkage groups are formed in the first group, and five linkage groups are formed in the second group. Sex type is controlled by the M locus. Genetic experiments have demonstrated that females are homogametic (mm) while male plants are heterogametic (Mm) for the sex locus. Two bulks of genomic DNA created by using 10 male and 10 female individuals in the population were screened to identify RAPD markers associated with the sex locus. RAPD marker OCP15-984 is closely linked with the M locus (7.6 cM).
Asparagus is a vegetable that presents an increase in yield when propagated by meristem culture. On the order hand, the rooting phase in asparagus is greatly affected by the previous phase, i.e,. multiplication. This species presents a better rooting performance when callus is formed at the shoot base. So, the aim of this work was to evaluate treatments during the multiplication phase, which also leads to callus formation at the shoot base. The initial explants came from shoots being cultivated in vitro. It was tested kinetin at: (0.0, 0.5, 1.0, 1.5, and 2.0) μM; ancymidol at (0.0 and 0.5) μM and NAA at (0.0 and 0.5) μM for both genotypes, which were cultured in a MS medium added to sucrose (30 g·L–1), agar (6.0 g·L–1) and myo-inositol (100.0 m g·L–1). Shoots bearing two buds were inoculated in 10-ml test tubes and placed in a growth room for 30 days when they were evaluated. The addition of kinetin significantly improved the number of buds and at 1.3 μM this growth substance presented the best results as number of shoots is concerned. NAA application promoted a negative effect on spear bearing. The addition of ancymidol in this phase did not improve the bud multiplication. It was shown that clone M14 performed better than the hybrid cv. Deco as multiplication is concerned.
Asparagus is a vegetable of great economic importance. It is a dioecius and perennial species mainly propagated by seeds, which makes difficult the breeding work as far as results are concerned. New biotechnological techniques such as tissue culture have been used in order to shorten the release of new cultivars. On the order hand, this process depends mainly on the rooting phase, which, for this species, is to some extent difficult. The aim of this work was to verify the influence of spear number on asparagus rooting. Two genotypes were studied: Clone M14 and cv. Deco, which is a hybrid (M14 × G27). These genotypes were tested with one, two, three, and four spears in a medium containing in mg/L: NAA (0.1); kinetin (2.0); ancymidol (0.5). Sucrose was added to 30 g/L and agar at 6.0 g/L. The pH was adjusted to 5.9. The evaluations were performed 30 days later. Four-spear asparagus rooted better than the others; it was also observed longer roots for this treatment. Clone M14 rooted better than cv. Deco. These results show the importance of the starting explants to improve the in vitro rooting in asparagus.
6-Furfuxylamino purine (kinetin) at 0.1% plus indoleacetic acid (IAA) at 0.005 to 0.025% in lanolin, applied directly to the lateral buds at nodes on the basal portion of stems induced aerial crown formation with shoot growth.
Methyl l-(butylcarbamoyl)-2-benzimidazolcarbamate (benomyl), a systemic fungicide, added to modified Murashige and Skoog's medium regulated asparagus shoot and root development. Low levels of benomyl (10 to 50 ppm) promoted multiple vigorous shoot development. Higher levels of benomyl (100 to 250 ppm) caused the development of abnormally short, thick shoots and inhibited root formation. The enlargement of the shoots is due to proliferation of cortex, phloem, and xylem cells.
Asparagus plants freed of 3 viruses were obtained by aseptic culture of shoot tips and apical meristems. More plantlets developed from shoot tip cultures than from apicalmeristem cultures, but a much larger proportion of the meristem cultures were virus free. Consequently, the number of virus-free plants obtained by these 2 methods were approximately equal. The ease of excising and culturing shoot tips makes this the preferred method. The aseptic stock plants obtained are being used as the source of propagants for mass production of virus-free asparagus plants.