摘要:

Agrobacterium rhizogenesA4T and the shuttle vectorp WIT2 were used to transformSolanum tuberosumcv.iwawith a CaMV35S5'-thaumatin II-tm/3' chimaeric gene. Biologically active r-thaumatin was produced in the transgenic plants inducing a sweet-taste phenotype. This is in contrast to expression of thaumatin chimaeras inEscherichia coli, Bacillus subtilis, Streptomyces lividans, Saccharomyces cerevisiae,andKluyveromyces lactisby previous workers where no change of phenotype was detected. This work successfully combines the sweet flavour phenotype ofThaumatococcus daniellii, a plant difficult to cultivate, with a high-yielding temperate crop plant. The CaMV35S'-preprothaumatin II-tm/3' chimaera may be thought of as a palatability gene of possible commercial importance.

ISSN:0114-0671    

DOI:10.1080/01140671.1990.10428075

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The aerial dispersal and settlement of armoured scale into kiwifruitActinidia deliciosa(A. Chev.) orchards was assessed using scale-free kiwifruit trap plants. Greedy scaleHemiberlesia rapax(Comstock) invasion was monitored over five seasons from 1985 to 1990 in an orchard adjacent to taraire treesBeilschmiedia taraireBenth. and Hook. f. Two major periods of invasion occurred in summer and autumn corresponding to the two scale generations on taraire. The intensity of invasion varied between generations and seasons with a peak rate of 8.7 scale/ 100 leaves per day in January 1987. Scale invasion was highest in kiwifruit blocks immediately adjacent to the taraire trees and declined in blocks further away. A survey of 25 kiwifruit orchards identified clear gradients in both greedy scale and latania scaleH. lataniae(Signoret) settlement, with higher levels closest to host plants. Scale invasion was reduced where host plants were removed or when host plants were regularly sprayed with insecticides after trimming to ensure full coverage of the sprays. An assessment of the risk of scale invasion into kiwifruit orchards is considered important in determining both the frequency and timing of insecticide applications in order to obtain a scale-free crop.

ISSN:0114-0671    

DOI:10.1080/01140671.1990.10428076

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Epiphyas postvittana(Walker) resistant to azinphos-methyl caused 1.7 and 5.4% fruit damage in 1983/84 and 1985/86 in apple orchards at Moutere Bluffs, New Zealand. Surveys from 1984 to 1989 of resistance in orchards and scrub nearby showed 3.5% survival of the diagnostic dose (LD99.95) in January and 7.6% survival in April. Survive did not increase between years. Catches in pheromone traps inside affected orchards indicated high levels of male activity despite regular application of chlorpyrifos. Mating disruption, along with the application of chlorpyrifos, was investigated as a possible solution to the continued inability to achieve economically acceptable leafroller control with insecticides alone. Two ha of apple trees were treated with Shin Etsu Chemical Co. dispensers (1000/ha) containing (E)-11-tetradecenyl acetate and (E,E)-9, 11-tetradecadien-1-yl acetate (56.5 and 2.8 mg per dispenser), in January 1987. No males were caught for over 11 months after the pheromone application. Harvest damage of the apple variety ‘Sturmer Pippin’ by lightbrown apple moth in the 1986/87 season was reduced to 0.02% from 5.4% in 1985/86. In January 1988, dispensers were applied at the same application rate in the same area, and one less chlorpyrifos application was made (total of 10). At harvest, 0.02% fruit damage was again detected. In 1988/89, the area treated with pheromone dispensers was increased to 10.6 ha, and the application made in November 1988. Fruit damage in the block treated for the third year was reduced to 0.0072% despite the elimination of three insecticide applications. Packhouse assessments indicated that fruit from three orchards in the area treated with pheromone and which received 6–7 insecticides averaged the same or less damage compared with fruit on similar blocks after 9–11 insecticide applications without pheromone. Implications for the use of mating disruption with insecticide applications are discussed.

ISSN:0114-0671    

DOI:10.1080/01140671.1990.10428077

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The effect of varying plant population and spatial arrangement on the production of buttercup squash (Cucurbita maximaDuchesne) was examined. Plant populations were set between 0.2 and 6.2 plants/m2in rows 1.5 and 3.0 m apart and at equidistant spacing within and between rows. The spatial arrangement of the plants in the three planting patterns had little effect on the production and fruit size of the squash compared with the effects of plant population. It was concluded that squash exhibited high elasticity in relation to the spatial arrangement at planting with row width and rectangularity of planting having much less influence on production parameters than plant population. Increases in plant population gave a progressive decline in the size of the individual squash plants and the number and weight of the fruit. Fruit number/m2of fruit heavier than 0.8 kg increased from 1 to 2/m2as populations increased from 0.23 to 2.5 plants/m2but they then declined. Average fruit weight declined from 1.9 kg at low plant populations of 0.2–0.4 plants/m2to 1.2 kg at populations 2.2–2.5 plants/m2, and below 1 kg at a plant population of 4 plants/m2. Significant numbers of squash above 2 kg were only achieved at low populations and only obtained with a considerable loss of potential yield. At low plant populations 3.0-m row plantings gave a greater percentage of larger fruit. As the plant populations increased the fruit size became more uniform. Total fruit yield increased to the highest calculated yield of 29.5 t/ha at a plant population of 3 plants/m2and then gradually declined. Above 2.2 plants/m2, the crop yield was predominantly in the fruit size range of 0.9–1.1 kg/fruit and sowing plant populations above 2.2 plants/m2would only be beneficial if this size of fruit was marketable. It is recommended buttercup squash be planted at populations of 1.8–2.2 plants/m2.

ISSN:0114-0671    

DOI:10.1080/01140671.1990.10428078

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Pre-harvest sprouting in wheat grains can cause serious processing problems. This paper summarises the regional incidence of sprout damage in New Zealand since 1928. For the 15 years from 1971 to 1986, an overall increasing risk of sprout damage was found towards southern latitudes. Hence, Otago and Southland generally had the highest proportion (24.7 and 23.7% respectively) of their wheat crops damaged by pre-harvest sprouting. The lowest risk areas were Nelson/Marlborough (2.5% sprout damage), North Island (4.9%), and North (5.9%) and Central Canterbury (3.6%). Indeed, these latter regions could well be suited to growing white-grained or high quality, sprout-susceptible red wheats. Historically, white-grained wheat cultivars such as ‘Arawa’ have been highlighted in harvest reports as being particularly vulnerable to sprout damage.

ISSN:0114-0671    

DOI:10.1080/01140671.1990.10428079

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

An instrument designed for easy field measurements of kiwifruit volume or weight is described. Volume (or weight) calculated from a single length measurement has a resolution of ± 1 cm3(g) permitting individual fruit growth to be monitored on a weekly basis. The assumption that the density of kiwifruit is 1 gm/cm3is shown to be a very good approximation. Variations in fruit shape cause the average error in a single measurement to be 8%. Data collected are displayed with resolutions of 1 cm3(g) for operator verification and are transferable to a portable personal computer to simplify data storage and analysis and to minimise handling errors. With this arrangement, a single operator can measure over 2 500 fruit in 4 h. The use of fruit growth information for assessing orchard practices such as irrigation management and for the early prediction of harvest fruit size in relation to target yield is discussed.

ISSN:0114-0671    

DOI:10.1080/01140671.1990.10428080

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Buds of ‘Valencia’ orange implanted in ‘Troyer Citrange’ rootstocks remain dormant for variable periods. A range of growth substances was applied either to the buds before implantation or through a wick following bud union with the stock in an attempt to promote rapid budburst. Soaking the buds in solutions before budding caused the death of some buds, particularly with gibberellic acid solutions. 6-benzylaminopurine promoted earlier budburst in most circumstances and may be helpful in nursery practice; other growth substances produced variable results.

ISSN:0114-0671    

DOI:10.1080/01140671.1990.10428081

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The role of pollination in seed production and fruit development of the feijoa (Acca sellowiana(Berg) Burret) was examined in the partially self-fertile cultivar Apollo. Growth and quality attributes of fruit from cross-, self-, and open-pollinated flowers were markedly different. Cross-pollination gave the highest fruit set, fruit weight, and pulp (endocarp) development. More seeds were present in fruit from cross-pollination than in those resulting from selfing. Seed distribution within the fruit was not affected by pollination treatments. Correlations between seed number and fruit weight, and seed number and internal fruit quality (pulp development), were found in the feijoa cultivars Apollo, Triumph, Mammoth, and Gemini. In ‘Apollo’, a correlation between seed number and fruit shape was also found. It is concluded that pollination of feijoa can have significant effects on fruit uniformity via its effect on seed production.

ISSN:0114-0671    

DOI:10.1080/01140671.1990.10428082

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The relationships between seed set and fruit weight and shape were studied on four nashi (Pyrus serotinaRehder varcultaRehder) cultivars Hosui, Kosui, Nijisseiki, and Shinsui. The carpel number ranged between four and eight per fruit with each carpel having the capacity to carry two seeds. The number of seeds per fruit was significantly correlated with fruit weight with ‘Nijisseiki’ showing the highest fruit-weight increase per seed. The seed number per carpel and the total weight of seeds per carpel were related to fruit shape. Even seed distribution around the fruit core was related to evenly shaped fruit. On the basis of the levels of seed set observed, considerable potential exists for raising the nashi quality by optimising pollination and seed set.

ISSN:0114-0671    

DOI:10.1080/01140671.1990.10428083

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Fusarium graminearumSchwabe was consistently isolated from stub dieback lesions on carnations in the Auckland region of New Zealand. Fusarium stem rots of carnation are also caused byF. culmorum(W.G. Smith) Sacc. andF. avenaceum(Ft.) Sacc. in New Zealand. Pathogenicity ofF. graminearumisolates to carnation was confirmed.

ISSN:0114-0671    

DOI:10.1080/01140671.1990.10428084

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor