摘要:

Strawberry (Fragaria × ananassaDuch.), like many other crops, has large numbers of cultivars both in breeding programmes and in commercial production. Problems with the accurate identification of cultivars have arisen. These difficulties are exacerbated by the need for unequivocal identification by vegetative characters alone when plants are clonally propagated from elite stocks before transplanting for fruit production. Thus, accurate identification at all stages of plant growth is essential if costly errors are to be avoided. In New Zealand, the varieties are characterised solely by morphological characters. An analysis of 17 strawberry cultivars in Auckland showed that there is substantial intra‐cultivar variability for many of the characters. This, when coupled with poor discrimination between cultivars for many of the characters, leads to difficulty in their use for identification purposes. Additionally, it was often found that our profile for a cultivar differed from that in the New Zealand Plant Variety Rights (PVR) description. Furthermore, there were often differences in the rating of the morphological characters between the New Zealand PVR description and the United States Patent for the same cultivar. However, a cluster of 14 vegetative, flower, and fruit characters could be used to identify the 17 cultivars used in this study. A significant problem of identification still remains for the plant breeder/propagator who deals almost exclusively with vegetative plants because vegetative characters alone are not sufficient for accurate identification.

ISSN:0114-0671    

DOI:10.1080/01140671.2000.9514128

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Pseudomonas aureofaciensPA147–2 produces an antibiotic that inhibits the growth ofPhytophthora megaspermavar.sojae,the causative agent of root‐rot disease of asparagus (Asparagus officinalis). To assess the potential use of PA147–2 as a biocontrol organism, we report preliminary findings of a field application of PA 147–2 to asparagus crowns. To determine the ability of PA 147–2 to suppress Phytophthora rot, asparagus crowns inoculated with PA 147–2 were planted in Eyre shallow fine sandy loam soil inoculated withP.megaspermavar.sojae.During the 6‐month trials, PA147–2 was isolated from inoculation points with a decreasing frequency. Harvesting and analysis of asparagus plants revealed that inoculation of crowns with PA147–2 resulted in a 55.8% increase of fern dry weight in comparison to untreated plants. Preliminary field trial results suggest the direct inoculation of asparagus crowns with PA147–2 before planting causes a statistically significant increase in the yield of plant material in the presence ofP.megaspermavar.sojae.

ISSN:0114-0671    

DOI:10.1080/01140671.2000.9514129

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Seventy‐four isolates of fungi includingTrichodermaspp. (18),Gliocladiumspp. (12),Coniothyrium minitans(39),Chaetomium globosum(3),Chrysosporium luteum(1), andFusariumsp. (1) were screened for ability to parasitise sclerotia ofSclerotinia sclerotiorum.Seventeen isolates killed all sclerotia after 4 weeks of incubation, with a further 15 isolates reducing sclerotial viability to less than 20%. These 32 isolates were screened in a second sclerotial parasitism test, where solid substrate ( 1 % kibbled maize:perlite colonised with antagonist) was incorporated into soil. Twenty‐four isolates significantly reduced sclerotial viability compared to the untreated control, withC. minitansConio, CH1, T5R4 2g, A69, and T5R4 2i giving the greatest reduction.C. minitansisolates showed considerable variation in their ability to parasitise sclerotia with some showing high activity but others little or no activity. Two New Zealand isolates (A69 and T5R4 2i) and two overseas isolates (CHI and Conio) were compared further. Increasing the length of the incubation period after treatment of sclerotia with C.minitansresulted in a decrease in the viability of sclerotia and an increase in the infection of sclerotia byC. minitans.This effect was significantly greater for isolates CHI and Conio compared with A69 and T5R4 2i. Incorporation of spores of the four isolates into soil (1 × 106spores/g soil) reduced sclerotial viability, with all isolates of antagonists surviving in the soil for the 2‐week duration of the experiment. Variation in the susceptibility of threeS. sclerotiorumisolates to sclerotial parasitism byC. minitansCHI and A69 was observed, withS. sclerotiorumisolate S9W1 the most susceptible and isolate S35 the least.

ISSN:0114-0671    

DOI:10.1080/01140671.2000.9514130

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

ISSN:0114-0671    

DOI:10.1080/01140671.2000.9514131

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Ciborinia camelliaeKohn is the most destructive pest or disease problem of camellias (Camelliaspp.) The pathogen is related to common and widespread plant pathogens in the generaSclerotiniaandBotrytinia(anamorph=Botrytis). Sclerotia form in infected petals and remain dormant in plant debris until the next season. In early spring, apothecia are produced from the sclerotia and release windborne ascospores. Infection causes the petals to turn brown and the flowers to fall prematurely. The disease has been identified in Japan (1919), the United States (1938), New Zealand (1993), and parts of Europe (1999). It has now spread over the lower North Island and upper South Island of New Zealand, with isolated outbreaks in Christchurch and Auckland. Control of this disease has proved difficult even though: (1) only camellia flowers are infected, (2) there is no secondary infection, and (3) ascospores are present for only 2–3 months each year. To date, fungicides have given less than satisfactory control of the disease and possible control measures are reviewed. Interest in potential biocontrol agents is growing but remains an unexplored alternative. Resistant varieties offer the best management option for the future.

ISSN:0114-0671    

DOI:10.1080/01140671.2000.9514132

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The effects of three planting media (50:50 peat:pumice,Pinus radiatabark, and soil) at two nutrient rates (1.0 and 4.0 kg/m3Nutricote) were assessed on sandersonia (Sandersonia aurantiaca(Hook.)) tuber production, the incidence of tuber russeting, and subsequent performance of tubers. Tuber weights were greater at the higher nutrient rate. Lighter tubers were produced in the bark medium than in the peat:pumice or soil. Tuber russeting was less, and commercially acceptable, at the low nutrient rate in all media. At the high nutrient rate russeting was greater in tubers grown in peat:pumice and soil compared to those grown in bark. At the high nutrient rate tissue concentrations of K, N, S, and P were greater. Tubers grown in bark had lower concentrations of N and S compared to tubers grown in soil and peat. At the high rate of nutrition tuber sprouting in the subsequent season was less in the tubers grown in soil and peat:pumice compared to the bark‐grown tubers. Stem length, stem weight, flower number, and vase life from tubers produced in bark at the high nutrient rate were similar to those produced in the soil and peatpumice media at the low nutrient rate. There was no improvement in production indices for the tubers grown in soil or peat:pumice at the high nutrient rate. These findings show that if grown in peat:pumice or soil, sandersonia tubers should be produced at low nutrient levels to reduce the incidence of tuber russeting and to improve subsequent forcing. If grown in bark media, higher nutrient rates can be used to maintain forcing quality without causing high levels of russeting.

ISSN:0114-0671    

DOI:10.1080/01140671.2000.9514133

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

ISSN:0114-0671    

DOI:10.1080/01140671.2000.9514134

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

ISSN:0114-0671    

DOI:10.1080/01140671.2000.9514135

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor