摘要:

An experiment to partition the components of variation in selected lines of triticale was conducted at Lincoln, Canterbury, New Zealand. Genetic variation, genotype × environment interaction, and phenotypic stability of 20 quantitative characters, as well as biochemical variation were studied in 11 hexaploid triticale lines. For the quantitative study, the lines were grown in four environments. The randomised complete block design was used in each environment. Data were collected on an individual plant basis except for five characters, measured on a plot basis. The results showed that genetic variation for most of the characters was high as expressed by the high broad sense heritability (>50%). Biochemical variation showed major differences between lines, though each line, except ‘Till’ and ‘Salvo’, was relatively homogenous. Genotype × environment interaction was strong for 16 characters. Lines such as ‘Lasko’, ‘Salvo’, ‘Presto’, ‘Juanillo’, ‘Aranui’, and ‘Swans’ have great potential for triticale yield improvements as they had average stability and were well adapted to all environments. Of the early maturing lines—'Fulis’, ‘Juanillo’, ‘Swans’, and ‘Till’ are likely to be the best for incorporation in the breeding programme as they had average stability and could be harvested earlier than other lines.

ISSN:0114-0671    

DOI:10.1080/01140671.1995.9513862

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Insecticides were applied to kiwifruit(Actinidia deliciosa)in February and April 1992 and April 1993. A bioassay technique was used to measure levels of greedy scale,Hemiberlesia rapax(Comstock), crawler settlement on fruit at various times after insecticide application. Organophosphate and pyrethroid residues remaining on the fruit were measured but not the mineral oil residues. The February and April 1992 trials showed that diazinon, chlorpyrifos, and diazinon/permethrin gave shortlived protection compared to phosmet, mineral oil, and pirimiphos‐methyl/permethrin. The residual times for 50% of fruit to be settled by scale in the April 1993 trial were: pirimiphos‐methyl/ permethrin, half rate <8 days; 1% Citrole mineral oil, 8 days; pirimiphos‐methyl/permethrin, full rate 16 days; 1% Sunspray Ultra‐Fine mineral oil, 19 days; 2% Citrole, 21 days; and 2% Ultra‐Fine, 24 days. Estimates of residue levels at which 50% of fruit were settled by scale were generally below or similar to the maximum residue levels set by the Codex Alimentarius Commission. The potential for reducing residues at harvest is discussed.

ISSN:0114-0671    

DOI:10.1080/01140671.1995.9513863

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The literature concerning the breeding of brassicas resistant to cabbage aphid(Brevicoryne brassicaeL.) and the interaction between different cultivars and various populations of the insect is reviewed. SixBrassicaaccessions selected for their different responses to a population ofBrevicoryne brassicaein England were tested in the glasshouse against three New Zealand populations of the insect. All six brassicas were also tested in the field at Lincoln, New Zealand. Under caged conditions in the glasshouse accessions ofBrassica fruticulosaCyrillo andB. spinescensPomel were shown to have high levels of antibiosis resistance to all three aphid populations expressed in terms of low production of young. In the field, very few aphids settled on the plants of these twoBrassicaspecies demonstrating high levels of antixenosis (non‐preference) resistance. The cabbage ‘Derby Day’ and New Zealand rape ‘Rangi’ supported a rapid increase in aphid populations in the glasshouse and were heavily infested in the field. A collard cultivar ‘Green Glaze Glossy’ was heavily infested in the field but proved to possess partial levels of resistance in the glasshouse tests. An accession ofB. insularisMoris was non‐preferred in the field and possessed a level of antibiosis resistance similar to the collard. There was no evidence of the existence of cabbage aphid biotypes to overcome resistance in the three populations studied.

ISSN:0114-0671    

DOI:10.1080/01140671.1995.9513864

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Disease severity keys are described and illustrated for powdery mildew (Erysiphe pisiDC.) and downy mildew (Peronospora viciae(Berk.) Caspary) of pea (Pisum sativumL.), and powdery scab(Spongospora subterranea(Wallr.) Lagerh. f. sp.subterraneaTomlinson) of potato (Solanum tuberosumL.). The keys consist of illustrations of pea leaves or potato tubers in 11‐point (0–10) severity scales of arbitrary proportions of surface areas diseased. The keys were constructed from hand drawings of pea leaflets or potato tubers, with colonies or lesions drawn to resemble typical infections of the respective diseases. Proportions of surface area of plant parts “diseased” on drawings were confirmed using computer‐assisted image analysis. The drawings were then scanned into computer storage for manipulation into illustrated keys for publication. The complete keys, or abbreviated versions, have been used for assessing severity of the diseases in recent research on crop loss assessment, disease control, susceptibility assessment, and disease epidemiology. They also provide bases for accurate disease severity assessment in commercial pea and potato crops. Copies of the disease keys are available from the senior author.

ISSN:0114-0671    

DOI:10.1080/01140671.1995.9513865

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Sixty‐three strains ofMycosphaerella fijiensisMorelet obtained from variousMusahosts in a range of different countries and localities were inoculated to juvenile plants of a standard set ofMusagenotypes. Individual strains had consistent but different patterns of pathogenicity on the host set. Some genotypes (SF215, 11–249 ('Saimea'), ‘Grande Naine') were susceptible to practically all isolates. Others, e.g., ‘T8’ and ‘Calcutta’, were resistant to some isolates but susceptible to others. Strains from Papua New Guinea and the Pacific Islands exhibited a wide range of pathogenic diversity. Some strains from those regions were pathogenic on juvenile plants of genotypes commonly used as sources of resistance in breeding programmes ('Calcutta’, ‘Paka’, and ‘PisangLilin'). These strains may threaten resistant progeny derived from those genotypes. Analysis of pathogenicity of strains collected over 4 years in Rarotonga, Cook Islands, has confirmed field observations that ‘Paka’ resistance is no longer effective on that Island. ‘Paka’ virulence has been found to be widespread in strains from the Pacific Islands and Papua New Guinea. Juvenile plants of ‘Yangambi’ (AAA), generally considered to be resistant toM. fijiensis,were susceptible to strains which were virulent on ‘Paka’. The availability of pure cultures of strains with differential virulence on specificMusagenotypes will facilitate the analysis of the inheritance of resistance toM. fijiensis.

ISSN:0114-0671    

DOI:10.1080/01140671.1995.9513866

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The maturation and storage quality of six ‘Golden Delicious’ x ‘Red Dougherty’ apple (Malus domesticaBorkh.) selections (3561, 4354, 4396, 4766, 4772, and 5029) were investigated for one season. Three selections (4396, 4354, and 4772) were studied for a further season. Selections matured at different rates and the timing of increased internal ethylene concentrations and starch pattern indices varied between selections. Fruit of Selection 4772 from all harvests developed severe internal browning in storage. Selections 5029, 4772, 4354, and 4396 were susceptible to superficial scald but except for Selection 4772 incidence of the disorder declined with progressive harvest date. Appropriate harvest periods will need to be based on market criteria and consumer acceptability.

ISSN:0114-0671    

DOI:10.1080/01140671.1995.9513867

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The response of three grain crops to drought was determined in a series of experiments in a mobile rainshelter at Lincoln, Canterbury, New Zealand. For winter wheat and spring barley, the critical potential soil moisture deficit (Dc) beyond which yield was affected was independent of drought timing, but was much smaller for barley than wheat. Both crops showed similar yield responses to drought above their Dc. In contrast, Dcfor maize increased as the season progressed, and yield was much less sensitive to drought once Dcwas exceeded. Although yield response was mostly associated with grain number in wheat and barley, mean kernel mass was also reduced as drought stress increased. Grain yield in maize was correlated with mean kernel mass, and uncorrelated with grain number.

ISSN:0114-0671    

DOI:10.1080/01140671.1995.9513868

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Fruiting canes on kiwifruit vines (Actinidia deliciosa(A. Chev.) C. F. Liang et A. R. Ferguson ‘Hayward') were pruned to length either at the usual time during winter, or much later, during spring. Pruning of replacement canes during spring is known as late tipping. Previous studies in Te Puke, the major kiwifruit‐growing region of New Zealand, have shown that late tipping can increase budburst, and therefore the yield, of kiwifruit vines by between 22 and 39%. In the current work, trials were carried out in three kiwifruit‐growing regions of New Zealand to determine the range of regional responses to late tipping. When data from this trial were combined with previously published data we found that changes in the number of flowers per winter bud (FWB) in response to late tipping were inversely related to the proportion of budburst (BB) on the canes tipped at the normal time during winter: increase in FWB(%) = 125–251 × (BB)r2=0.73. Therefore, late tipping will not increase flower production on vines which are already destined to have a high budburst. This situation is likely to occur regularly in climates as cool as southern New Zealand, or northern Italy, but less frequently in the milder climate of Te Puke, New Zealand.

ISSN:0114-0671    

DOI:10.1080/01140671.1995.9513869

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

In the 1989/90 season 6‐year‐old Lincoln‐canopy trained ‘Nijisseiki’ and ‘Hosui’ Asian pear (Pyrus pyrifoliaNakai) trees were part‐tree sprayed with 400 ppm ethephon ((2‐chloroethyl)phosphonic acid), applied 15 days after full bloom (DAFB) or hand thinned (leaving one fruitlet at each fruiting site 56 DAFB) in a split‐plot design with ethephon applied to main plots and hand thinning to subplots. Ethephon reduced fruit set of ‘Nijisseiki’ and ‘Hosui’ by 37 and 15%, respectively, removing on average one ‘Nijisseiki’ fruitlet per cluster. Independently of hand thinning, ethephon reduced mean fruit weight of ‘Hosui’ at harvest by 34 g (21%), but ‘Nijisseiki’ was unaffected. Hand thinning increased fruit weight of ‘Nijisseiki’ and ‘Hosui’ at harvest by 19 g each (25 and 13%, respectively), only in the absence of ethephon application. Ethephon and hand thinning each increased return bloom of ‘Nijisseiki’ whereas only hand thinning increased return bloom of ‘Hosui’. In the same season, a whole‐tree spray of ethephon (400 ppm applied 15 DAFB) increased fruit set of ‘Doyenne du Cornice’ European pears (Pyrus communisL.) by 51%. In the 1990/91 season, ethephon applied at 400 ppm 15 DAFB reduced fruit set and fruit weight at harvest, and increased the incidence and severity of flesh spot decay of ‘Nijisseiki’ fruit, when assessed after 12 weeks of storage at 2°C. Ethephon also increased return bloom. In contrast naphthaleneacetic acid (NAA) (7.5 ppm, 15 DAFB) had no effect on fruit set or fruit weight, but reduced flesh firmness at harvest by 1.96 N (6%). In a second experiment in 1990/91 ethephon was foliage applied to Lincoln‐canopy trained ‘Nijisseiki’ trees 15 DAFB at 0, 200, 400, 600, or 800 ppm a.i. Fruit set was significantly reduced in proportion to the ethephon concentration with 800 ppm reducing fruit set by 62% compared to the nil treatment. Increasing ethephon concentrations significantly decreased mean fruit weight and flesh firmness at harvest, and significantly increased fruit soluble solids concentration and seed number. The incidence and severity of the fruit disorder, flesh spot decay, increased significantly in proportion to the concentration of ethephon when assessed after 12 weeks of storage at 2°C. Ethephon at both 600 and 800 ppm increased the area of individual spur leaves whereas neither shoot leaf nor spur leaf number were affected. Specific leaf weight (mg/ cm2) was increased irrespective of ethephon concentration. Ethephon significantly increased return bloom the year after treatment by an average of 52%.

ISSN:0114-0671    

DOI:10.1080/01140671.1995.9513870

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Thirty tree samples of ‘Gala’ apples(Malus domesticaL.) were used to determine distribution and standard deviations (SD) of individual fruit weight in orchards throughout New Zealand. A positive correlation was found between average fruit weight and the SD. The coefficients of variation (CV), the ratio of SD to average fruit weight, showed less variation than SD. The recorded fruit size distributions were used to estimate the percentage of fruit in each count size. An example table for three mean fruit weights and five CVs is provided.

ISSN:0114-0671    

DOI:10.1080/01140671.1995.9513871

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor