摘要:

Flight activity ofRhopalosiphumspp. was recorded in a suction trap between 1981 and 1987. Field studies on cereals in Canterbury during the period 1984–1987 showed thatRhopalosiphum padiL., the most frequent species, was usually present at low densities and only occasionally reached maxima greater than 10 aphids per tiller on wheat (Triticum aestivumL.) or barley (Hordeum vulgareL.). Greater numbers ofR. padiwere found on rye (Secale cerealeL.) than on wheat, barley, oats (Avena sativaL.), or ryegrass cv Tama (Lolium perenne × multiflorum).Rhopalosiphum maidis(Fitch) was frequent on barley in 1985 and 1986 but was rare in other years.Rhopalosiphum insertum(Walker) andR. rufiabdominalis(Sasaki) were recorded on cereals in autumn 1987. Comparison of suction trap catches and numbers of winged aphids landing on cereals showed thatR. padiconcentrated on barley crops to a lesser extent than didR. maidisorMetopolophium dirhodum(Walker).

ISSN:0114-0671    

DOI:10.1080/01140671.1989.10428003

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The objectives of this work were to determine whether maize hybrids from different climatic regions were specifically adapted to different temperature environments, or whether adaptation to a wide range of temperature environments could occur. In addition, information was obtained on the characteristics associated with temperature response. This information will be of value when screening maize varieties for diverse temperature environments. It will also provide information on problems that may arise when adapting maize to environments substantially different to the U.S. Corn Belt. The vegetative growth and development of highland tropical, lowland tropical, northern latitude flintdent, and Corn Belt Dent maize hybrids were compared in controlled environment rooms at three day/night temperature regimes. The lowest temperature regime (16/6°C) was near the minimum for sustained autotrophic growth. From previous work, the intermediate temperature regime (25/20°C) was expected to produce the highest dry weight and leaf area at defined growth stages. The highest temperature regime (35/30°C) was near the maximum for sustained growth. For each harvest, entire plants were harvested when a mean of five or eight leaves were fully expanded as indicated by the appearance of the ligule. Different responses to temperature were observed among the hybrids. The highland tropical hybrids (NZIA×5-113 and H28) emerged and grew faster than all other hybrids in the cool 16/6°C environment, but grew more slowly than the other hybrids in the 35/30°C environment. In contrast, the lowland tropical hybrid (3M071) and Corn Belt Dent hybrids (A665×H99 and P3901) emerged and grew more slowly than the highland tropical hybrids in the 16/6°C environment, but faster than the highland tropical hybrids in the 35/30°C environment. The hybrid A665×NZ1A, a cross between Corn Belt Dent and highland inbreds; the Corn Belt Dent hybrid A665×W153R; and the dent-flint cross A665×CO255, showed an intermediate type of response to this range of temperatures. None of the hybrids performed well in both the 16/6 and 35/30°C environments except perhaps A665×NZ1A. This indicates that adaptation to temperature is generally specific and it may be difficult to produce hybrids with broad temperature responses. The difference in growth between A665×W153R and A665×H99 at 16/6°C and 35/30°C indicates that Corn Belt Dent hybrids can vary considerably in their response to temperature. At all temperatures, the highland tropical hybrids partitioned more dry weight to their shoots, maintaining shoot to root ratios similar to those at 25/20°C. However, low leaf area ratios reduced potential leaf areas and possibly dry weights.

ISSN:0114-0671    

DOI:10.1080/01140671.1989.10428004

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The way in which crop processors can influence the timing of a crop's harvest is by the choice of cultivar and planting date. However, the crop duration (time between planting and harvest) is substantially affected by the weather. Processors' records illustrate the magnitude of these effects. The mean crop duration for the sweet corn cultivar NK51036 was 111 days for the 1980/81 to 1984/85 seasons in the Manawatu, but the range was 38 days. The practical problem facing the processor is how to allow for these effects when planning optimal use of factory plant and labour.

ISSN:0114-0671    

DOI:10.1080/01140671.1989.10428005

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A consistent relationship has previously been established between temperature and the time from sowing to maturity for several sweet corn cultivars grown at three sites in New Zealand. The present paper uses this relationship, together with 13 years of historical temperature records, to simulate the effects of cultivar, season, date of planting, and site on the date of harvest. Making such assessments from existing factory records alone is not feasible.

ISSN:0114-0671    

DOI:10.1080/01140671.1989.10428006

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Seventeen weed control treatments were used around five species of newly planted alders (Alnus cordata, A. glutinosa, A. incana, A. inokumae, andA. rubra). The treatments that gave the best control during the first season were a mixture of terbumeton and terbuthylazine, diuron applied either once or twice, and appropriate surface cultivation. However, terbumeton/terbuthylazine should be used with caution around first year plants. Other treatments which performed adequately were: oxyfluorfen applied twice; linuron as a pre-emergence treatment; and simazine either following an application of activated amitrole before planting, or (at double the rate) on cultivated ground after planting. Amitrole applied soon after planting intensified drought stress 3 months later. None of the herbicide treatments caused lasting damage to the young trees. There were no significant differences between species or provenances in their responses to these treatments. The herbicide treatments had no effect on the size or numbers of root nodules.

ISSN:0114-0671    

DOI:10.1080/01140671.1989.10428007

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A joint application of paclobutrazol to soil and Promalin paint to branches before the second growth season combined paclobutrazol flower spur induction and Promalin branching effects to produce compact and well-branched ‘Bing’ sweet cherry trees. Paclobutrazol and paclobutrazol + Promalin advanced bloom date by 6–7 days, and delayed harvest by about 4 days as compared with other treatments. The effect of Promalin combined with paclobutrazol persisted for over one year, improving fruit set compared with trees treated with paclobutrazol only and also producing the greatest rate of fruit growth up to 24 days after anthesis. The heaviest fruit was produced by application of paclobutrazol, followed by paclobutrazol+Promalin, control, and Promalin trees. In the third year after planting, trees treated with paclobutrazol+Promalin yielded 4.4 kg of cherries whereas trees treated with Promalin or paclobutrazol and control trees yielded 2.2, 1.8, and 2.0 kg, respectively.

ISSN:0114-0671    

DOI:10.1080/01140671.1989.10428008

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Pre- and post-harvest treatments were investigated for their effects on the incidence of storage rots in fruit of cultivars ofCucurbita maximaandC. moschata. Fruit artificially damaged by removing stalks at harvest was more prone to rot than undamaged fruit. Fungicides applied during fruit development reduced storage rots in some cultivars but the effects were not large. Development of storage rots was not affected either by curing of fruit (14 days at 22°C and RH >90%) to assist wound healing or by hot water treatment (5 or 10 min at 50°C) to eradicate infection. Increasing the length of time (after maturity) fruit remained attached to the vines before harvesting appeared to increase its susceptibility to storage rots.

ISSN:0114-0671    

DOI:10.1080/01140671.1989.10428009

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Nysius huttoniwas caged on plots of two New Zealand cultivars, Rongotea and Karamu, at the watery-ripe stage of grain development. Cultivar Karamu had 100% visibly injured kernels and three times more insect bite marks than ‘Rongotea’ which had 89% injured kernels. Grists containing 50% bug-damaged wheat of either cultivar produced bread with severe bug-damage characteristics. Grists containing 1–10% bug damaged kernels produced bread of reduced quality but not classified as bug-damaged. Both cultivars were equally susceptible to the effects of bug damage in the baking test. SDS-sedimentation tests and SDS-PAGE revealed proteolysis of gluten proteins consistent with that previously demonstrated for bug-damaged commercial wheat lines. High and low molecular weight glutenin subunits were affected by insect enzyme. This study provides further evidence to suggest thatN. huttoniis one of the insect species causing technologically significant bug damage in New Zealand wheats.

ISSN:0114-0671    

DOI:10.1080/01140671.1989.10428010

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Tuber weight loss, specific gravity changes, and french fry and crisping quality in three processing cultivars (Kaituna, Ilam Hardy, and Tekau) and one fresh market cultivar (Iwa) were studied during storage following storage harvests in 1983, 1984, and 1985. In 1985, ‘Russet Burbank’, the predominant processing potato in the USA, was included in the trial because of strong commercial interest in New Zealand. Each year, potatoes were stored at 6°C and 11°C for 25 weeks. In 1984 and 1985, potatoes stored at 11°C were treated with sprout inhibitor. Without sprout inhibitor at 11°C, ‘Tekau’ and ‘Iwa’ stored the best with less weight loss, and better crisping and french fry quality than the other cultivars. At 6°C, ‘Kaituna’ had a relatively low weight loss but the crisps were darker and the french fries gave a lower score than the other cultivars. ‘Ilam Hardy’ lost most weight at both temperatures but the crisps and french fries produced were light in colour and scored well after 20 weeks of storage. ‘Iwa’ had a low weight loss for potatoes stored at 11°C with sprout inhibitor. ‘Russet Burbank’ stored very well at both temperatures having a low weight loss and producing good crisps and french fries.

ISSN:0114-0671    

DOI:10.1080/01140671.1989.10428011

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

On four sites, in each of two cropping years, fertiliser nitrogen applied in the early spring to tillering ‘Rongotea’ wheat sown in late autumn concurrently improved grain yield, flour protein content, dough water absorption, loaf volume, loaf texture, and mechanical dough development bake score. In the drier cropping year, the overall mean rate of response in grain yield to fertiliser nitrogen was lower than in the wetter cropping year. Conversely, overall mean rates of response to fertiliser nitrogen in flour protein content, flour extraction, dough water absorption, loaf volume, loaf texture, and mechanical dough development bake score were higher in the drier cropping year. Kernel weight and dough work input responded erratically to fertiliser nitrogen in both cropping years.

ISSN:0114-0671    

DOI:10.1080/01140671.1989.10428012

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor