摘要:

AnAgrobacterium-mediated transformation system has been developed for introducing foreign genes into the three most important potato cultivars in New Zealand (‘Ilam Hardy’, ‘CRD Iwa’, ‘CRD Rua’). Leaf segments of in vitro plants were co-cultivated with a disarmed strain ofAgrobacterium twnefaciens(LBA4404) harbouring the binary vector pCGN200. This vector contains two chimeric neomycin phosphotransferase genes (OCS-NPT II-OCS and 35S-NPT II-TML) that confer kanamycin resistance to plant cells. Potato cell colonies were selected with resistance to 250 mg/litre kanamycin and regenerated into complete plants. Proof that these plants were transformed involved both biochemical and molecular evidence. Enzymatic expression of neomycin phosphotransferase II was detected in leaf extracts using a dot blot assay. Southern analysis confirmed integration of the foreign DNA into the potato chromosomal DNA. The cultivar ‘Iwa’ was especially amenable to bothAgrobacterium-mediated transformation and the regeneration of transgenic plants.

ISSN:0114-0671    

DOI:10.1080/01140671.1991.10418098

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

There is considerable potential for the improvement of the slow and irregular germination of celery seeds (Apiurn graveolensL.) by pre-sowing hydration treatments, but poor germination performance as a result of drying seeds after treatment is a recurrent problem. Over the temperature range 5–20°C the onset of seed germination is determined by a thermal time relationship, but a pre-sowing treatment temperature of 15°C was identified as the most effective for the two celery cultivars—‘Tall Utah 52–70’ and ‘Green Giant Hybrid’—when the seeds were only surface-dried before sowing. However, conventional air-drying of treated seeds at 20°C caused severe delays in germination and decreased uniformity. Higher treatment temperatures reduced the adverse effect of drying on the seeds but resulted in little or no germination advantage because of thermodormancy, which was particularly evident at 25°C. Deleterious effects of drying-back were avoided, and in some instances further germination enhancement gained, by slowing the rate of drying which was achieved by exposing the treated seed to a series of controlled humidity atmospheres at 80, 68, and 48% RH for various times.

ISSN:0114-0671    

DOI:10.1080/01140671.1991.10418099

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The level of natural outcrossing, after hand emasculation and open pollination, and the effectiveness of the Shell Chemical Co. Hybridization Agent (WL84811) to induce male sterility were studied in hexaploid triticale (Triticosecale× Wittmack). The results indicated a high level of outcrossing in triticale after hand emasculation and open pollination. Cross-pollination by wind readily occurred under Canterbury conditions giving up to 78% seed set, suggesting that hybrid seed could easily be produced in hexaploid triticale either by hand emasculation or by use of a chemical gametocide.

ISSN:0114-0671    

DOI:10.1080/01140671.1991.10418100

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Pollen, from pellets gathered by bees, was used to pollinate kiwifruit flowers artificially. Pollen was applied at a number of rates after suspending in an aqueous medium or mixing with one of three different diluents to get a powder formulation. Resulting fruit size was less at lower rates of pollen application. At such low rates (generally < 1.0 mg/flower), a linear relationship was detected between pollen application rate and final fruit size, in some seasons. Some powder formulations (e.g., that usingLycopodiumspores) seemed less effective than the aqueous suspension. However, the best formulation for pollination of kiwifruit was made with an inert powder. This formulation effectively set fruit at rates of pollen as low as 0.037 mg/flower, although at this rate fruit size was reduced as a result of inadequate seed set.

ISSN:0114-0671    

DOI:10.1080/01140671.1991.10418101

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The Satsuma mandarin (Citrus unshiuMarc.) cultivars ‘StuntFree’, ‘Tanikawa’, ‘Hayashi’, and ‘Ishikawa’ were compared with the standard industry cultivar ‘Silverhill’, over 7 years, at the Te Puke Research Orchard in the Bay of Plenty, New Zealand. ‘Silverhill’ proved to be the best cultivar, with fruit achieving soluble solids concentrations (SSC) of 9.3–9.8% and SSC/acid ratios (SSC:A) of 7.2–8.4. The mid-season cultivars ‘Stunt Free’ and ‘Tanikawa’ had a similar period of commercial maturity to ‘Silverhill’ but as they produced fruit of poorer quality and exhibited weaker tree vigour, they do not appear to have any commercial prospects. Fruit of the late-maturing cultivars ‘Hayashi’ and ‘Ishikawa’ were also of poor quality, with high acidity and low SSC: A ratios. Although mandarin fruit quality can be expected to be higher in districts with a warmer climate than Te Puke (and/or by the use of improved cultural techniques), it is unlikely thatthe late- maturing Satsuma cultivars ‘Hayashi’ and ‘Ishikawa’ would be suitable for commercial production in New Zealand.

ISSN:0114-0671    

DOI:10.1080/01140671.1991.10418102

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A trial was conducted in the Huon Valley of Southern Tasmania in the 1986–87 season, where 26-year-old red ‘Delicious’ apple trees were thinned with ethephon sprays 1 or 2 days after full bloom. Application rates of 250–1500 g a.i. ethephon/ha were used. These were applied in a concentration range of 35–750 ppm and with spray volumes of 1000, 2000, 4000, 6000, and 7000 litre/ha using a conventional, hydraulic, air-blast sprayer or a hand lance. The volume of spray used was of critical importance in the ethephon thinning of mature red ‘Delicious’ trees. The results showed that at least 4000 litre/ha was necessary to effectively thin these trees and the effect was not closely allied to the concentration or dosage used. The majority of concentrations lower than 100 ppm proved quite effective as thinners when sprayed at higher volumes. Thinning rates were correlated with volumes rather than concentration or dosage of spray used. This was expressed in the form of a linear, negative regression between fruit thinning or a significant positive regression between mean fruit weight and spray volume. This emphasised the need to increase the volume of spray used to thin red ‘Delicious’ with ethephon rather than increase the concentration. Thinning with ethephon was highly dependent on the volume rather than on concentration or dosage of spray.

ISSN:0114-0671    

DOI:10.1080/01140671.1991.10418103

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Partially covering a block of ‘Fuyu’ persimmon trees with polyethylene (plastic) cover increased fruit colour, weight, soluble solids concentration, and lowered soluble tannins in each of two seasons. These improvements to fruit quality may have been the result of higher temperatures in the block partially covered with plastic. Plastic covering also increased spring shoot growth and advanced flowering by 7 days. The beginning of harvest was advanced by 1 week, and the spread of harvest reduced by 10 days. The effects of plastic covering on fruit quality varied between seasons. The increases in fruit colour and soluble solids concentration were greater in 1989 than in 1990. The increase in fruit weight and the decrease in soluble tannin content were greater in 1990 than in 1989.

ISSN:0114-0671    

DOI:10.1080/01140671.1991.10418104

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Establishment failures of asparagus caused by Phytophthora rot were controlled effectively with metalaxyl (Ridomil MZ72) applied as a dip at a concentration of 300 mg metalaxyl/litre to crown transplants before planting. Dipping crowns was more effective than applying metalaxyl as an in-furrow treatment after transplanting and covering the crowns with soil. Metalaxyl was more effective than phosphorous acid solutions or solutions of captan and benomyl for controlling Phytophthora-related establishment failures. Seedling transplants, which were planted later in the spring than crowns, were an effective way of avoiding the cool, wet conditions that favour Phytophthora rot during establishment.

ISSN:0114-0671    

DOI:10.1080/01140671.1991.10418105

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Wound repair by fruits of theCucurbita maximahybrid ‘Delica’ involved the rapid sealing of the wound by a phloem exudate, which hardened on contact with air, and the development of a wound periderm and callus tissue beneath the layer of hardened exudate. Fruits which had stopped expanding at the time of wounding produced callus tissue in sufficient quantity to eventually rupture the wound periderm and expose the underlying tissue to colonisation by fungi. In rapidly expanding, young, fruits the growth of callus was relatively slight, the wound periderm remained intact, and the amount of scar tissue over the wound was much less than that which grew over wounds in older fruits. The scar tissue produced by the wound repair process, particularly in older fruit, increased the potential for subsequent invasion by fungal pathogens since rots occurred much more often at the edges of scar tissue than elsewhere on the fruit surface.

ISSN:0114-0671    

DOI:10.1080/01140671.1991.10418106

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The effect of controlled atmosphere (CA) regimens on the storage quality of ‘Granny Smith’ apples has been examined over two seasons. Fruit quality was assessed by physical parameters, incidence of storage disorders and sensory evaluation. There were small differences in fruit quality between 2% O2/2% CO2and 3% O2/3% CO2atmospheres, with slight advantages of 2% O2/2% CO2in terms of titratable acidity. A 2% O25% CO2atmosphere resulted in fruit of the same firmness as those in 2% O2/2% CO2, although titratable acid levels were lower. Compared with 2% O2/2% CO2, fruit from a 1% O2/ 1.5% CO2atmosphere were not significantly firmer or more acid. Low (0.75%) CO2concentrations with either 2% or 3% O2resulted in softer fruit, suggesting that moderate levels of CO2are important for maintenance of flesh firmness. Fruit from 2% O2/ 0.75% CO2atmospheres were also less green than fruit from 2% O2% CO2, but there was no effect of CO2on colour when O2levels were 3%. Low CO2concentrations resulted in a high incidence of coreflush and flesh browning. Sensory analysis did not detect differences between fruit from any of the CA treatments except 2% O2/0.75% CO2, which had the lowest acidity, lowest juiciness, and less overall acceptability.

ISSN:0114-0671    

DOI:10.1080/01140671.1991.10418107

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor