摘要:

A regional trial series on 12 triploid hop selections together with four check triploid culti vars was conducted. The aim was to assess commercial potential of the hop selections and to estimate the importance of genotype × environment (G × E) interaction. The triploids were derived from crossing three tetraploid female cultivars—'Hallertauer’, ‘Smoothcone’, and ‘First Choice'—with diploid males. Genotype × environment interactions were statistically significant for all of the characters measured. However, the magnitude of the interaction components of variance were much less than that caused by genotype variation. Of the 12 selections tested two were considered to have commercial potential as high alpha acid producing types. They were subsequently evaluated in more detail for several hop chemistry characteristics. One of the two selections has now been named ('Pacific Gem') and released for commercial production whereas the other is currently still under brewing trial evaluation. Modifications to the evaluation of advanced hop selections under New Zealand conditions is discussed in light of the relative importance of G × E interaction to the main effect of genotypes.

ISSN:0114-0671    

DOI:10.1080/01140671.1994.9513799

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The development rate response to temperature of greedy scale,Hemiberlesia rapax, instars was determined from development times over a range of constant temperatures. A diurnal temperature simulation technique employing sine and exponential functions was coupled with these relationships and used to drive a distributed development period model of greedy scale phenology. The model was assessed against field data for its ability to predict first instar presence at one site in the Waikato, New Zealand. The model was then used to examine possible seasonal variation in the timing of first instar greedy scale production over the range of kiwifruit growing climates in New Zealand. The model duplicated field data for first instar presence well. The results obtained from simulations for a range of seasons and districts are discussed.

ISSN:0114-0671    

DOI:10.1080/01140671.1994.9513800

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

CO2assimilation rate of a ‘Hayward’ kiwifruit(Actinidia deliciosa(A. Chev.) C.F. Liang et A.R. Ferguson) adult vine was measured during the summer of 1989 by two methods. One, an open‐system chamber enclosing a whole vine canopy, was designed for continuous investigation of photosynthesis via the monitoring of external light, humidity, air flow, and air CO2concentration. The other was the ADC‐LCA1 system, which sampled only a part of a single leaf. The results indicate that photosynthesis rate value increases with light intensity in both instances, but, with respect to the single‐leaf CO2measurements, the whole canopy CO2exchange measurement shows lower variability. Also absolute values for single leaf photosynthesis are higher than those observed for the whole plant.

ISSN:0114-0671    

DOI:10.1080/01140671.1994.9513801

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Shoots were regenerated from 12‐mm diameter leaf discs derived from greenhouse plantsof Limonium perigrinum(Bergius), with either zeatin or thidiazuron (TDZ), the latter producing five times the number of shoots. After 8 weeks exposure to a modified Murashige and Skoog basal medium (BM) supplemented with 3.0 mg/litre TDZ, an average of 13 shoots/disc formed, 90% of which were ≤ 1 mm long. There was no significant difference in the total number of shoots formed at 1.0–5.0 mg/litre TDZ, however at lower rates (1.0–2.0 mg/litre) a greater proportion of longer shoots (> 1 mm) developed. Shoots regenerated after 8 weeks from leaf discs exposed to BM with TDZ for from 2 h to 6 weeks before being transferred to growth‐regulator‐free medium. A mean of 4.8 shoots/disc formed from the shortest TDZ pulse period, with the majority being longer than 1 mm. Serial sections of discs pulsed with TDZ medium showed many suppressed shoot initials within the new tissue originating from the cut edge of the discs.

ISSN:0114-0671    

DOI:10.1080/01140671.1994.9513802

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A dry matter (DM) assay along with a qualitative and quantitative carbohydrate study were conducted on two Jerusalem artichoke(Helianthus tuberosusL.) cultivars—'Kharkov’ and ‘Violet de Rennes’. In addition to sucrose, glucose, and fructose, some inulin‐type glucofructosans were detected at all stages of development of the tubers. The carbohydrate content was found to average from 65 to 80% DM. The tubers lose a fraction of their carbohydrates in winter—27.6% for ‘Kharkov’ and 35.6% for ‘Violet de Rennes’.

ISSN:0114-0671    

DOI:10.1080/01140671.1994.9513803

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Casuarina cunninghamianaandC. glaucaare widely used for shelterbelts in New Zealand and have other utilitarian potential. Their nitrogen (N)‐fixingFrankiasymbiont does not occur naturally in New Zealand soils. Plants nodulated after artificial inoculation withFrankiacultureHFPCcI3 were planted on a horticultural‐quality Manawatu silt loam soil near Palmerston North. After 6–8 years, trees nodulated at planting were significantly larger in stem diameter and height (equivalent to 16–61% additional volume) over trees not nodulated at planting. Nodulated trees were also rated higher for vigour. Excavation of root systems revealed that nodules were confined to the residual zone of potting media around the original seedling root systems and there was no evidence ofFrankiaspreading through the soil to infect nearby roots. More widespread availability ofFrankiainoculum in the soil being explored by feeder roots might have increased nodulation and subsequent tree growth, but New Zealand soil temperatures are suboptimal for Casuarinaceae nodulation and N fixation.

ISSN:0114-0671    

DOI:10.1080/01140671.1994.9513804

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Fifty‐eight spring malting barley crops(Hordeum vulgareL. ‘Triumph') were monitored in the Rangitikei district, New Zealand (40°20'S), over three seasons beginning 1987/88 and covering a wide variation in soil moisture conditions during grain filling but small deficits before anthesis. The objectives were to: (1) document the range of variability of grain yield among locations and years; (2) determine if systematic patterns occurred in the dry matter (DM) accumulation and nitrogen (N) uptake; and (3) evaluate the effects these processes have on the partitioning of DM and N between the grain and the rest of the plant. Mean yearly grain yields (14% moisture) were 6.85, 5.12, and 5.07 t/ha, respectively. Grain number/m2accounted for 79% of the variation in grain yield. On average, 63% of the N in the above ground crop was derived from soil reserves, and 87% of the total N uptake occurred before anthesis. Pre‐anthesis processes had a major effect on crop characteristics at maturity. For example, the level of crop N at anthesis (indicative of pre‐anthesis N uptake) was a good predictor of the extent of post‐anthesis partitioning of N to the grain(r =‐0.75). Conversely, high post‐anthesis N uptake was generally not related to grain N concentration. Therefore, under dryland conditions, there is scope for improving yield by late applications of N without causing grain quality reductions. Management options for obtaining high yields of malting barley under non‐irrigated conditions are discussed. These include the use of crop N concentration at anthesis as an indicator of crop N status.

ISSN:0114-0671    

DOI:10.1080/01140671.1994.9513805

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The risk of sweet corn(Zea maysL.) crops failing to reach harvest maturity as a result of climatic variability among seasons was quantified for four locations on the east coast of New Zealand's South Island. Results of field experiments in the region showed that three representative cultivars had thermal time requirements from planting to maturity ranging from 1215 to 1320 °C days above a base temperature of 6°C. In simulations, crop success or failure was estimated for combinations of five hypothetical cultivar maturities and four planting dates spanning the ranges likely to be used in the region. Calculations used temperature records that ranged from 17 to 25 seasons depending on location. A crop was judged to fail if either its thermal time requirement was not met by 30 April or it was frosted before the requirement was met. Allowance was made for the fact that some “failed” crops were sufficiently close to maturity to be harvested successfully. Risk was negligible at Blenheim, the most northerly location, where seasonal mean temperature between 15 October and 30 April was 15.8°C and the first autumn frost occurred late. Timaru, the most southern location, had earlier frosts and a 13.7°C mean temperature, and risk of failure was high except for early plantings of early‐maturing cultivars. Lincoln, representing the intermediate area of central Canterbury, had a mean temperature of 14.6°C and a high risk of failure for late plantings of late‐maturing cultivars. This location is probably at the climatic limit for commercial sweet corn production with an acceptable level of risk, using currently available cultivars. A warming trend since 1928 has resulted in a substantial decrease in risk over the period. The analysis highlighted the marginal nature of the Canterbury climate, the effect on risk of the sensitivity of the crop's development rate to temperature, and indicated the potential benefit of any further climatic warming.

ISSN:0114-0671    

DOI:10.1080/01140671.1994.9513806

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Trials were carried out to assess the production of low‐virus and standard commercial bulbs of four narcissus varieties in southern New Zealand. In the first year, while attaining maturity, low‐virus bulbs showed field weight gains 83–126% greater than commercial bulbs. Low‐virus bulbs produced 32–87 offsets/100 bulbs, compared with 0–1/100 for commercial bulbs. In the second year, low‐virus bulbs showed similar field weight gains to commercial bulbs, but produced 45–386% more offsets. It is concluded that low‐virus bulbs provide superior yields to commercial bulbs grown under similar conditions in southern New Zealand, and that this superiority can be maintained for at least 2 years with the same stock. Under experimental conditions the yield of commercial varieties grown in the southern South Island considerably exceeds that reported for the same varieties grown under commercial conditions in Europe.

ISSN:0114-0671    

DOI:10.1080/01140671.1994.9513807

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Kiwifruit(Actinidia deliciosa(A. Chev.) C.F. Liang et A.R. Ferguson) cv. Hay ward from four orchards were treated with the dicarboximide fungicide, iprodione, applied as a preharvest spray or a postharvest dip to control stem‐end rot caused byBotrytis cinerea(Persoon: Fries). Differences in the incidence of stem‐end rot existed between orchards but in each orchard only low levels of infection were found. The incidence of stem‐end rot was lower in the fungicide dipped fruit than in fruit from the control or preharvest sprayed treatments. The proportion of dicarboximide resistance inB. cinereaisolates from fruit rots was highest in the fruit that were dipped. There were no consistent differences between orchards in the proportions of dicarboximide resistance. Iprodione residue levels were higher on the dipped than on the sprayed fruit.

ISSN:0114-0671    

DOI:10.1080/01140671.1994.9513808

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor