摘要:

A ‘Russet Burbank’ potato crop was subjected to 14 irrigation treatments in a rainshelter experiment at Lincoln, New Zealand in the 1987–88 growing season. In 12 treatments, plots were trickle irrigated and covered automatically by the shelter whenever rain fell, so that precise responses of yield and quality to water deficit timing and severity could be obtained. These treatments ranged from overwatering to withholding water to develop maximum potential deficits of up to 138 mm. The water stress treatments were applied either ac tuber initiation, early tuber bulking, or late tuber bulking (assessed by sampling spare plants). Except when fit was raining, these plots were exposed to prevailing climatic conditions. The two remaining treatments, which were outside the rainshelter, checked for direct effects of the shelter on the crop. One treatment was irrigated to achieve the same deficits as one of the treatments inside the rainshelter, and the other was not irrigated. Highest yields of process grade tubers (63 t/ha} were obtained from the overwatered plots. Among the drought-stressed treatments, the highest yields were 58 t/ha of process grade tubers, obtained from plots subjected to drought during tuber initiation; these had fewer bit larger tubers. Drought during late tuber bulking reduced process grade yields by 20%, with both tuber size and tuber number being reduced by up to 20%. Non-irrigated rainfed plots outside the shelter had low yields and small tubers because the season had half the average rainfall. The levels of water deficit imposed had no effect on tuber processing quality.

ISSN:0114-0671    

DOI:10.1080/01140671.1992.10422319

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

To test the potential for garlic cropping on southern South Island, New Zealand soils, two varieties of garlic, ‘Printanor’ and an unnamed red garlic variety, were grown on Otiake loamy silt at Kurow, North Otago and on Mataura silt loam at Wendonside, northern Southland, New Zealand. Under experimental conditions yields in the range 16–17 t/ha are obtainable at botte sites, similar to Chose obtained in Canterbury and Auckland. Irrigation lid pot increase yields at Wendonside. Pyruvate concentrations were 30% lover in southern-grown garlic than in ‘Printanor’ garlic grown in Marlborough, the main garlic-growing area of New Zealand. A taste panel could detect no difference between southern-grown red garlic and Marlborough-grown ‘Printanor’, but could detect a difference between ‘Printanor’ grown in the two regions. Commercial production of garlic on Otiake and Mataura soils appears feasible.

ISSN:0114-0671    

DOI:10.1080/01140671.1992.10422320

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Trials were conducted to determine yields of narcissi bulbs at three sites in Otago and Southland in South Island, New Zealand. The effect of irrigation was tested at two sites. Mataura silt loam soils at Wendonside, Southland, gave the highest yields. On this soil type, in a season with 67% of normal rainfall, irrigation increased yields by c. 6%, with some varieties showing yield responses up to 26%. Yields over two seasons were variable, but exceeded those reported for the same varieties grown in Europe.

ISSN:0114-0671    

DOI:10.1080/01140671.1992.10422321

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The efficiency of a pollen trap in trapping kiwifruit (Actinidia deliciosa) pollen pellets was investigated. The trap had an average daily efficiency of 16.5 and 16.7% on 2 consecutive days. Hourly efficiencies varied between 0 and 25% with the highest efficiency in the middle of the day which coincided with periods of maximum honey bee (Apis melifera) foraging activity. The amount of staminate pollen in foragers' corbiculae was closely related to the proportion of staminate pollen on their body indicating that pellets can be used as a measure of pollination efficiency.

ISSN:0114-0671    

DOI:10.1080/01140671.1992.10422322

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The gene encoding the 133 kDa insecticidal crystal protein ofBacillus thuringiensisvar.kurstakiisolate DSIR732, has been cloned intoEscherichia coli. The complete nucleotide sequence of the coding region of thecry732 gene, has been determined and indicated a large open reading frame (ORF) of 3534 nucleotides encoding a protein of 1178 amino acid residues, with an estimated molecular weight of 133 330 Da. In addition, the sequence of 387 nucleotides 5′ and 257 nucleotides 3′ of the coding region has been determined. Sequence comparisons of thiscry732 gene and its flanking regions with those of other Btcrygenes revealed that it is a member of thecryIA(c) class of Btcrygenes. Alignment of thecry732 nucleotide sequence with that of thecryIA(c) holotype gene sequence from BtkurstakiHD73 revealed only four nucleotide differences in the ORF, none of which resulted in amino acid substitutions, and one nucleotide difference in the region 5′ to the ORF. Nucleotide sequence comparisons suggested that thecry732 gene may have resulted from recombination events between thecryIA(c) genes of BtkurstakiHD73 and BtkenyaeHD558—2. Thecry732 gene has been expresed inE. coliand bioassays, using extraas ofE. coliproducing the 133 kDa Cry732 protein, have demonstrated that the recombinant protein retains its insecticidal properties against three species of leafrollers (Lepidoptera: Tortricidae).

ISSN:0114-0671    

DOI:10.1080/01140671.1992.10422323

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Epidemics on vine leaves of anthracnose, caused byElsinoe ampelinaShear, and of downy mildew, caused byPlasmopara viticola(Berkeley & Curtis ex de Bary) Berlese & de Toni, were studied in an Auckland vineyard during 11 seasons,1971/72/1981/82. Primary infection byE. ampelina, from conidia on cane lesions, occurred in late September—early October, within 4 weeks from budburst. An epidemic failed to develop in only one season, 1972/73, in which rainfall was unusually low. Leaves that escaped infection in their first 4 weeks generally remained free from anthracnose thereafter, and the most severe epidemics occurred in seasons in which the intervals between rain periods were short. Primary infection byP. viticola, presumed to be from oospores, occurred in November–early January, corresponding to the period from 2 weeks before anthesis to fruit set. Primary infections resulted in only small numbers of lesions. In 8 of the 11 seasons there was no downy mildew at the end of December on canes selected for detailed recording. Leaves did not become resistant with age, and in two seasons when epidemics did not begin until autumn most leaves eventually became mildewed. Rainfall of < 1 mm could provide moisture needed for infection byP. viticola. No downy mildew occurred in the driest season. In three seasons severe epidemics developed over periods of 50 days in summer/autumn with rainfall for the period ranging from 36 to 58 mm. In two seasons downy mildew became established in summer but epidemics failed to develop in 50 days despite rainfall in the periods of 99 and 234 mm, and temperatures similar to those in the epidemic seasons. Fungicide sprays protective against anthracnose should be applied from budswell to fruit set. Sprays to control downy mildew peel not be applied at the beginning of the season, and there are prospects for using a monitoring system as a basis for a control programme.

ISSN:0114-0671    

DOI:10.1080/01140671.1992.10422324

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Fifty-six field isolates ofFusarium solanifrom cucurbits, lucerne, and pens were testel for their pathogenicity on seedlings of their respective hosts and on fruit ofCucurbitaspp. Mating behaviour, including the sex (male (M) or female (F) or both), mating type (MAT1-1 or MAT1-2), and mating population (MP) was examined for 49 of these isolates by maling with known tester strains. Five cucurbit isolates were identified as MPI and five others as MPV. Nine pea, five lucerne, and one red clover strain were identified as members of MPVI. The remaining 24 isolates tested for mating behaviour were unable to mate with any of the testers used. There was clean evidence of host specificity of isolates in the seedling pathogenicity tests. For example, most isolates from peas showed moderate or strong pathogenicity to peas, weak or non-pathogenicity to lucerne, and non-pathogenicity to cucurbits. Cucurbit isolates were non-pathogenic or weakly pathogenic on peas and either non-pathogenic (MPV and non-mating strains) or strongly pathogenic (MPI strains) on cucurbits. Regardless of their host-specificity in the welling tests all strains in a representative sample from the three hosts were capable of producing lesions on wound-inoculated fruits of theCucurbita maximaF1 hybrid buffercup squash ‘Delica’, with over 90% of strains showing moderate or strong pathogenicity. Less than a third of the cucurbit isolates however, showed moderate or strong pathogenicity to unwounded fruit ofCucurbita moschata‘Waltham’. These results indicate that the ability to invade through the intact cuticle and epidermis is a major determinant of specificity.

ISSN:0114-0671    

DOI:10.1080/01140671.1992.10422325

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Fusariuminfection in field barley from the Waikato region of New Zealand was determined in 1989–91.F. avenaceumand the potentially toxigenicF. crookwellense, F. equiseti, andF. graminearumwere the most commonFusariumspp. isolated from leaf pisces and grain although the species varied with year and site. The incidence ofFusariuminfection was highest in the 1989 crop and may have been influenced by higher mean temperature and rainfall at asthesis in this crop than in the 1990 and 1991 crops. The incidence ofFusariuminfection on maize debris from previous crops was high. The incidence of infection of barley by other toxigenic fungi e.g.,Penicilliumspp. was very low and noAspergillusspp. were isolated.

ISSN:0114-0671    

DOI:10.1080/01140671.1992.10422326

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Flower senescence was observed in representatives of 102 genera from 33 monocotyledon families. This is the first comparative study to cover such a wide range of monocotyledons. All of the species studied are of horticultural importance as ornamentals or cut flowers. Observations were made on attached flowers (i.e., still on the plant) on plants growing under cultured conditions, and on detached flowers held in water. Emasculation and style removal was also performed on some of the flowers to prevent pollination occurring. Abscission of unpollinated flowers, and flowers that are persistent regardless of pollination, were both widespread. In contrast, abscission of floral parts (perianth, style, stamens) was much less common, occurring predominantly in the Liliales. This database will form the starting point for more detailed studies of senescence and variation between cultivars.

ISSN:0114-0671    

DOI:10.1080/01140671.1992.10422327

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

All the fruit from kiwifruit vines (Actinidia deliciosa(A.Chev.) C.F. Liang et A.R. Ferguson cv. Hayward) were dipped in 10 mg/litre solutions of forchlorfenuron (N-(2-chloro—4-pyridyl)-N-phenylurea) 35 and 36 days after full bloom at two sites in the 1989/90 season and 22 days after full bloom at one site in 1990/91. Growth curves showed that treated fruit grew 30–60% faster than untreated fruit, both during the rapid cell division and expansion phase (first 53–74 days after full bloom), and during the subsequent slower cell expansion phase through to harvest. The mean harvest weight of export quality fruit from forchlorfenuron treated vines was increased by 27–46% (average weight for three sites 143 g) compared to untreated fruit (107 g). Forchlorfenuron treatments did not influence overall rejection rates. Forchlorfenuron treatments appeared to increase some fruit shape defects but that was compensated by a reduction in pollination and blemish defects. At harvest, forchlorfenuron treated fruit had lower total soluble solids and flesh firmness than untreated fruit.

ISSN:0114-0671    

DOI:10.1080/01140671.1992.10422328

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor