摘要:

This 4‐year study was initiated to formulate a management package for producing high yields of high quality malting barley and involved large‐scale trials comparing the levels and interactions of nitrogen (N), irrigation, and disease and pest control on yield and quality. One ha each of autumn and spring sown crops were sown in mid Canterbury each year. In the first 3 years, low and high levels of irrigation (flood irrigation when gravimetric soil moisture in the top 150 mm of soil fell to either 15% or 20%) and two levels of disease and pest control (curative and preventative) were compared at different levels of N fertiliser (100, 200, and 300 kg N/ha in Year 1, and 0, 50, 100, and 200 kg N/ha in Years 2 and 3). In the fourth year, four levels of disease control (nil, curative, half preventative, and preventative) were compared along with four levels of N fertiliser (0, 50, 100, and 150 kg N/ha). The treatment means from all eight trials (but only the first six trials in the instance of malt extract, ears/m2, and grains/ear) were then analysed together to determine the overall effect of treatments and treatment combinations. This combined analysis showed that N fertiliser significantly increased yields (from 4.5 to nearly 7 t/ha), particularly at the high irrigation treatment and in autumn sowings (up to 8 t/ha). N fertiliser also increased percentage screenings (from 5 to 16%), particularly under curative disease and pest control. Grain N percentage was also increased with increasing N fertiliser levels (from 1.3 to 1.6%), especially in the spring sowing and under low irrigation. Malt fine extract was reduced by increasing N fertiliser (from 84.4 to 81.3% at 200 kg N/ha). Ears/m2increased by up to 50% with increasing N, especially in autumn sowings and under high irrigation. Grains/ear increased by 1.6 with increasing N fertiliser especially under curative disease and pest control.

ISSN:0114-0671    

DOI:10.1080/01140671.1993.9513740

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Honey bees(Apis melliferaL.) were shown to be able to discriminate between staminate (male) and pistillate (female) kiwifruit(Actinidia deliciosa)flowers. They exhibited floral sex constancy and showed an overall preference for pistillate flowers when visiting flowers on a tray. This indicates that honey bee pollination of kiwifruit is not a case of “mistake pollination”. Foragers also exhibited flower sex constancy between trips when foraging freely in a kiwifruit orchard. A number of foragers also had foraging areas that they returned to during consecutive foraging trips. Honey bees visited staminate flowers between 1 and 3 days old, and pistillate flowers between 1 and 5 days old in a season when pistillate anther dehiscence took 5 days. When pistillate anther dehiscence took only 3 days, foragers only visited flowers between 1 and 3 days old. This suggests that foragers are able to determine whether a kiwifruit flower contains pollen without having to land on it.

ISSN:0114-0671    

DOI:10.1080/01140671.1993.9513741

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Pheromone traps were operated weekly throughout the growing season for three key leafroller pests and codling moth at four orchard sites for up to 10 growing seasons in the Alexandra and Clyde districts (Central Otago) of New Zealand.Epiphyas postvittanaandPlanotortrix octowere the most commonly trapped species.Ctenopseustis obliquanawas caught in low numbers at all sites. All three species showed a trough in male flight activity in January between first and second generations.Cydia pomonellaoccurred at all four sites, exhibiting one generation per year, with flights continuing during the trough in leafroller activity. Prospects for reduced use of insecticides during this period therefore seem better on stonefruit than pipfruit since stonefruit are rarely attacked by codling moth.

ISSN:0114-0671    

DOI:10.1080/01140671.1993.9513742

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Erwinia amylovorainfection of either apple stem or leaf tissue resulted in xylem occlusion by a fibrillar matrix material, determined by Thiery’ s thiocarbohydrazide (TCH) test to be the extracellular polysaccharide fromE. amylovora.Plasmolysis of the xylem‐parenchyma was also detected and was most likely a result of a toxin produced by the pathogen. This plasmolysis resulted in the collapse and death of the cell. AnErwinia herbicolaisolate which had previously expressed inhibitory effects onE. amylovorawas contained at the site of inoculation.

ISSN:0114-0671    

DOI:10.1080/01140671.1993.9513743

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

In a trial to determine if flowering cherries(Prunus serrulataLindl.) were a source of little cherry disease, infection was found in seven of 10 species and cultivars tested. In an orchard trial with the cultivar ‘Lambert’, fruit symptoms of little cherry occurred in infected trees in the fifth year of fruiting, 8 years after planting. The symptoms also occurred in the two succeeding years, after which time the trial was terminated. The indicator ‘Canindex I’ showed more pronounced leaf reddening symptoms than the indicator ‘Van’, and has superseded it as an indicator for little cherry. Trees tested from old plantings of ‘Dawson’ sweet cherry(P. aviumL.) which had been shown to have good, true to type fruiting characteristics, were mainly free from little cherry disease.

ISSN:0114-0671    

DOI:10.1080/01140671.1993.9513744

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Pea, lentil, dwarf and broad bean crops were each monitored over two seasons for virus infection using sample surveys, ELISA, and indicator hosts to estimate disease incidence. The incidence of individual viruses in most crops was usually < 11%, exceptions include cucumber mosaic virus (CMV) in lentils and alfalfa mosaic virus (AMV) in broad beans. Multiple virus infections were detected in 55–100% of pea, lentil, and broad bean crops. Soybean dwarf virus (SDV), beet western yellows virus (BWYV), pea seed‐borne mosaic (PSbMV), and CMV were the most common aphid‐borne or seed‐transmitted viruses detected. AMV, CMV, BWYV, bean yellow mosaic virus (BYMV), and PSbMV were recorded from lentil and CMV and PSbMV from broad beans for the first time in New Zealand. Survey results are presented and their implications are discussed.

ISSN:0114-0671    

DOI:10.1080/01140671.1993.9513745

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Crop failures associated with asparagus replanting have been ascribed to a combination of microbiological and chemical influences. Extracts from asparagus roots and soil were examined to locate inhibitory chemicals. Analysis of root extract fractions in a seedling assay showed that phenolic and saponin components inhibited growth but the most inhibitory material was located in the amino acid/carbohydrate fraction. However, inhibitory asparagus soil extracts did not contain significant levels of active compounds (tryptophan, caffeic acid) identified from root extracts.

ISSN:0114-0671    

DOI:10.1080/01140671.1993.9513746

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The effect of nutrition frequency on the nursery growth of ex‐flasked transplants of two asparagus clones of two root grades was studied. Growth increased as feeding frequency with 100:34:100 mg/litre NPK increased from one feed in 5 days to daily feeding. Growth optima were not detected, indicating that higher nutrient concentrations may be required to achieve optimum growth rates. There was little overall difference between the clones with respect to absolute growth parameters, but the relative growth rate of the shoots differed between clones. Relative growth rate between root sizes (within clones) was similar. Tissue analysis indicated differences in nutrient uptake between clones. The practical implications of this work are discussed.

ISSN:0114-0671    

DOI:10.1080/01140671.1993.9513747

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The surface morphology, and cuticle and outer epidermal cell wall anatomy of developing squash fruit(Cucurbita maximaDuch. hybrid ‘Delica') were examined using light microscopy, and scanning and transmission electron microscopy. During the period from flowering to maturity, fruit surface morphology changed from epidermal cells with raised dome‐shaped outer periclinal walls, inconspicuous smooth wax and three trichome types, to a surface with depressions and ridges encrusted with waxy deposits and devoid of trichomes. The thicknesses of both cuticle and cell wall increased to maturity. The four distinct areas of the fruit surface— green, white, rib, and ground‐spot—had similar cell wall and cuticle thickness at maturity, although cuticularisation of anticlinal walls was less developed in the ground spot area. None of the areas observed showed special features that might predispose the surface to fungal infection.

ISSN:0114-0671    

DOI:10.1080/01140671.1993.9513748

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

In barley, some herbicide and fertiliser recommendations are linked to reproductive development. Three cultivars of barley were sown on seven different dates in 2 years in mid Canterbury, and their reproductive development related to more easily measured parameters such as calendar time, thermal time, and leaf emergence. Morphological growth stages were recorded in both years, and, in addition, reproductive growth stages were recorded in the second year. Development time decreased with delayed sowing up to “ear at 1 cm”, but not thereafter. However, thermal development time with a base temperature of 4°C, and pnotothermal development time with a base temperature of 0°C and a base photoperiod of 8 h, were unaffected by sowing date. In both years, thermal time from ear emergence (GS49) to hard dough (GS87) averaged 460 day degrees above 4°C, and photothermal time 314 day degrees above 0°C adjusted for photoperiod. ‘Magnum’ took up to 88 day degrees above 4°C longer, and up to 55 day degrees above 0°C adjusted for photoperiod longer, to reach a particular growth stage than did ‘Triumph’, with ‘Illia’ generally being intermediate. Double ridge occurred when there were three or four fully expanded leaves; ear at 1 cm occurred between five and six leaves; apical primordium stage occurred between six and seven leaves; and first node occurred about the same time that seven leaves had fully expanded.

ISSN:0114-0671    

DOI:10.1080/01140671.1993.9513749

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor