Asparagus ( Asparagus officinalis L.) is a well-managed/assisted crop, with good water and nutrient availability ( Yeasmin et al., 2013 ). Asparagus decline is associated with both abiotic and biotic factors. Abiotic factors associated with the
We have used isozyme techniques (SGE) to assess variation and begin construction of a genetic map of the Asparagus officinalis genome. Isozyme extraction buffers, electrophoretic buffer systems, and isozyme stability during storage were evaluated. Isozyme expression under different environmental conditions was also examined. Thirty-four enzymes were evaluated for their usefulness as genetic markers in A. officinalis. Of these 34, 13 had sufficient activity and resolution on the gels for isozyme analysis. Of the 13 enzyme systems resolved, polymorphisms were observed in aconitase, endopeptidase, malate dehydrogenase, phosphoglucomutase, and shikimate dehydrogenase. Segregation of putative alleles is presented for ACON, END, MDH, PGM and SKDH isozymes. Co-segregation data showed linkage between a SKDH locus and a PGM locus. The isozyme analysis also included Asparagus densiflorus `Sprengeri' and revealed that aspartate aminotransaminase, endopeptidase, and triosephosphate isomerase would be potentially useful for verification of cell fusion products between the two species.
Frost damage to `Jersey Giant' asparagus (Asparagus officinalis L.) spears was evaluated in noncovered and black plastic-covered field plots following a spring frost episode. In the noncovered plots, 78% of spears were killed as compared to only 17% under the plastic rowcovers. Laboratory studies using natural frost simulations indicated that the spears of both treatments were frost hardy to -2.8C. Air temperature data in the field plots during the frost episode indicated that spears in noncovered plots were at lower temperatures (-4.0 to -4.8C vs. -2.8C) ≈4 to 5 hours longer than spears under rowcovers. The large difference in the spear-kill may be due to the difference in the combined effect of the degree and duration of freezing to which the spears had been exposed.
Asparagus officinalis L. cultivars were evaluated for resistance to asparagus stem blight caused by Phomopsis asparagi (Sacc.) Bubák under controlled environmental conditions. The plants were inoculated with the vinyl tube and cotton inoculation method. Disease severity assessments, based on the percentage of diseased plants and the disease index, were made 4 weeks after inoculation. Estimates of the percentage of diseased plants ranged from 33% to 80%, and the disease index ranged from 28 to 79. None of the cultivars and lines showed high resistance, but there were significant differences in disease susceptibility among the cultivars and lines.
The use of a sex-linked molecular marker for early sex diagnosis in the dioecious species Asparagus officinalis L. was evaluated. Screening of random genomic probes as a part of a restriction fragment length polymorphism mapping project resulted in the identification of a sex-linked (6.9 cM) marker. The usefulness of this molecular tool was compared to morphological markers for prediction of gender in several genotypes. The level of polymorphism detected by this probe was high, and the level of incorrect sex attribution, as determined by this method, was low (≈7%).
Endogenous gibberellins (GA) and cytokinins (CK) were extracted from asparagus (Asparagus officinalis L.) spear tips, purified, and determined by lettuce hypocotyl and amaranthus bioassays, respectively. There was no quantitative difference in GA-Iike activity between heterogametic male and female spears. The major GA fraction in asparagus spears has 1 OH group. Asparagus spears contain 3 major fractions of CK-like activity. Fraction 1 eluted from Sephadex LH-20 and C18 HPLC columns with or before zeatin-riboside. Fractions 2 and 3 eluted in a similar pattern to IPA-riboside and IPA, respectively. There were higher levels of CK fraction 2 and trends toward higher levels of fraction 1 and total CK in female than in heterogametic male spears. There were also higher CK:GA ratios in female than in heterogametic male spears. The data support the hypothesis that sex in asparagus is controlled in part by CK levels or by CK:GA ratios.
The effects of culture media, culture modes, and carbon sources on plating efficiencies of protoplasts of two genotypes of Asparagus officinalis L. were investigated. Protoplasts grew best in a semisolid culture system containing half-strength MS medium with 1 mg NAA/liter, 0.5 mg zeatin/liter, 0.6 M glucose, and 0.1% Gelrite. The plating efficiencies were 12.5% and 8.1% for genotypes G 203 and G 171, respectively. Embryogenic calli were produced from protoplast-derived microcalli after culturing on MS medium with 1 mg 2,4-D, 3% sucrose, and 0.2% Gelrite. The somatic embryos were initiated, matured, and then germinated to plantlets in MS medium containing 0.1 mg NAA/liter, 0.3 mg 2-iP/liter (EMM), and different levels of carbohydrates. Transfer of somatic embryos from EMM with 10% glucose to EMM containing 2% sucrose produced the highest number of bipolar embryos and plantlets. The plantlets regenerated shoots and roots in MS medium with 3% sucrose, 0.1 mg NAA/liter, 0.1 mg kinetin/liter, and 1.28 mg ancymidol/liter. Cytological analysis of these plants revealed 2n = 20 chromosomes.
Asparagus ( Asparagus officinalis L.) is a perennial plant belonging to the Asparagaceae family and is a popular vegetable consumed in many different areas of the world ( Benson, 2012 ). It can be easily divided into edible and inedible parts. It
Asparagus ( Asparagus officinalis L.) is a popular stem vegetable consumed worldwide. It is a source of functional substances including rutin and protodioscin ( Wang et al., 2003 ). A recent statistical report suggested that China is the largest
Asparagus ( Asparagus officinalis L.) is a perennial plant belonging to the Asparagaceae family and a popular vegetable cultivated and consumed in many different areas of the world ( Benson, 2012 ). Asparagus is rich in healthy functional