Varietal differences in the susceptibility of Brussels sprouts to lepidopterous pests

The attack by cabbage caterpillars on open-pollinated cultivars of Brussels sprouts at Wellesbourne was recorded approximately weekly from July to October in 1973 and 1974. The red-foliaged cv. Rubine was much less attacked by Pieris rapae than any of the twenty-five green-foliaged cultivars tested, the least attacked of which were The Aristocrat, Continuity, Evergreen and Pride of the Market. Rubine also showed some resistance to attack by Mamestra brassicae and Evergestis forficialis, as did The Aristocrat. Continuity, though as resistant as any of the cultivars to E. forficialis, was not resistant to M. brassicae. No evidence of antibiosis was found and resistance, based on non-preference, is considered to result from ovipositing P. rapae adults discriminating against the red colour of Rubine and against the leaf composition (relative volatile content) of the green-foliaged resistants. This could also apply with M. brassicae and E. forficialis.     

Wind‐modulated landscape effects on colonization of Brussels sprouts by insect pests and their syrphid antagonists

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Seasonal changes in aphid populations on Brussels sprouts

Populations of Brevicoryne brassicae (L.) and Myzus persicae (Sulz.) were assessed weekly on Brussels sprouts at Wellesbourne, from July onwards in each of 3 years. A peak of B. brassicae numbers occurred every year about the end of July, and in 1968 and 1970 this was larger than the September peak. Some alates were produced in the generation born to the June immigrants and the dispersal of those produced at the end of July consistently brought a decline in B. brassicae populations in early August. In 1968 and 1970, however, outbreaks of entomogenous fungi which followed rain, added considerably to this decline. Records of predators and parasites indicated that these natural enemies had only a minor effect on aphid numbers. M. persicae colonized sprouts slightly earlier than B. brassicae; in 1969 and 1970 its numbers in July were low and some persisted after the first week of August in 1968 only. In each year the first eggs of B. brassicae were laid at the beginning of October, but viviparae were still numerous for a further 7 to 10 weeks.     

Effect of Light and Ethylene upon Cytokinin Levels in Seed of Spergula arvensis

The breaking of dormaney in Spergula orvensis L. seed by lightand ethylene is accompanied by severalfold increases in thelevels of endogenous cytokinins prior to germination, the largestrise being observed in the cytokinin-ribotide fraction. Pretreatmentof seed with cytokinins does not, however, substitute for thelight or ethylene requirements.     

A Population Study of Spergula arvensis: II. Genetics and Breeding Behaviour

Genetical work has shown that one locus and two alleles areinvolved in the inheritance of a seedcoat character of Spergulaarvensis and that the hetero-zygous plants are intermediatebetween the two types of homozygous plants. It is thus possibleto translate directly the observed geographical distributionof plant frequencies into distribution of gene frequencies.The inheritance of a hairiness character is less straightforward,but in this case also there is a close relation between phenotypefrequency distribution and gene frequency distribution. Using the fact that plants heterozygous for the seedcoat characterare easily recognizable, it is possible to make an estimateof the amount of outbreeding in nature. The values obtainedrange from o to 3 per cent.     

A Population Study of Spergula arvensis: I. Two Clines and their Significance

Two seed-coat forms (the presence or absence of papillae) andtwo hairiness forms (medium or densely hairy) of Spergula arvensisare differently distributed through the British Isles, theirrelative frequencies being correlated with latitude and altitude.The proportions of the non-papillate and densely hairy formsincrease with increasing distance from Kent to the north-north-westand also with increasing altitude. A possible explanation is that the diverse forms indicate selectivedifferences. Experiments have been carried out to test thishypothesis and the evidence supports it. The non-papillate formproduces a lower proportion of fertile capsules than the papillateform when grown at a high temperature and low humidity. Alsothe non-papillate seeds germinate more readily than the papillateseeds at low temperatures, whereas at higher temperatures thereverse is true. It is suggested that hybrid vigour, fluctuating selection intensities,and migration may all play a part in maintaining the observeddistribution of the various forms.     

Influence of crop background on natural enemies of aphids on Brussels sprouts

The most abundant natural enemies of aphids on Brussels sprout crops were Syrphidae, different species being attracted differentially to weedy or weed-free plots according to whether they were more host-plant-orientated (e.g. Melanostoma spp., Platycheirus spp.) and thus affected directly by the background, or more aphid-orientated (e.g. Syrphus balteatus) and so less affected by background than by aphid numbers. Oviposition by Melanostoma spp. was usually much greater in weedy sprout crops than on sprouts in bare soil, and their eggs were also very abundant on weeds. Eggs of other syrphid species were scarcer on weeds. In contrast to Melanostoma, Platycheirus spp. usually oviposted preferentially on sprouts growing in bare soil. Oviposition by S. balteatus was in response to aphid abundance and thus tended to become greater on sprouts in bare soil. Notably more adults of non-aphido-phagous Syrphidae were caught over weedy than over non-weedy Brussels sprout plants. Anthocoris nemorum nymphs and adults were very common on sprout plants and weeds in the weedy crop but were scarce on sprouts in bare soil; A. nemorum oviposited on white and yellow charlock (Raphanus raphanistrum and Sinapis arvensis) occasionally. Parasitism of Brevicoryne brassicae by Diaeretiella rapae appeared to be related to aphid numbers and was only indirectly influenced by the crop background. Field experiments with green and brown cloth backgrounds showed that some syrphids were attracted to green; A. nemorum was relatively scarce over both artificial backgrounds. It is concluded that decreased natural enemy action is partly responsible for the initially greater abundance of B. brassicae in a weed-free crop of Brussels sprouts than in a weedy crop.     

Influence of crop background on aphids and other phytophagous insects on Brussels sprouts

More Brevicoryne brassicae and other alate aphids were caught in yellow water-traps in a weed-free crop of Brussels sprouts than in a crop with a weedy background. More B. brassicae colonized Brussels sprout plants in bare soil than in weeds; very few alatae were attracted to cruciferous weeds in the crop. Results in 1 yr suggest that initially larger populations on the weed-free sprouts became smaller than populations on the weedy sprouts because the larger aphid population attracted more natural enemies. Aleyrodes brassicae and certain Lepidoptera were also more abundant on sprout plants in bare soil than on sprouts surrounded by weeds; more adult A. brassicae were caught in water traps over the bare soil. More A. brassicae were present on sprout plants surrounded by a green than by a brown cloth background but the differences were not significant (P < 0–05). Numbers of B. brassicae on sprout plants with green and brown backgrounds varied greatly and did not differ significantly. In field cages, B. brassicae alatae were more attracted to potted sprout plants surrounded by bare soil than to ones surrounded by rings of living or cut grass or by artificial green rings. This effect was greater with small than with large sprout plants surrounded by grass rings. The maintenance of a limited weed cover is considered potentially useful in integrated control of some brassica pests.     

Resistance to attack by Brevicoryne brassicae among plants of Brussels sprouts

Because they remained almost uncolonized by the cabbage aphid (Brevicoryne brassicae (L.)) throughout the growing season, plants of Brussels sprouts were singled out in each of 4 years, from plots heavily infested with the aphid, as possibly being resistant to attack. Clones of these plants were established from cuttings and tested in a controlled environment by inoculation with B. brassicae and later, in the field, by natural infestation. The tests confirmed that some of the plants were resistant to the aphid, and the most resistant of those from the first year of the work proved at least as resistant as any subsequently found. The resistance was expressed as antibiosis, but in the field host non-preference was also shown by incoming winged aphids. The possibility that biotypes of B. brassicae might exist, to which the resistant sprout clones were not necessarily resistant, was investigated using B. brassicae collected from sprouts from each of several areas in England. Eight sprout clones, seven of which were known to be resistant, and the other susceptible, to B. brassicae from Wellesbourne were tested with these other B. brassicae. The results showed that biotypes of the aphid, with differing abilities to colonize respective sprout clones, existed in each area, and of the seven sprout clones resistant to the Wellesbourne aphid, only one appeared never to be fully susceptible to one or more of the other biotypes of B. brassicae.     

Effect of spray application technology on the biological control of aphids in Brussels sprouts

A field trial was carried out to evaluate different application techniques for crop penetration and biological efficacy of aphid control in Brussels sprouts. Six different application techniques were tested at a pressure of 4.0 bar in a field trial in 3 parallels at the Provincial Vegetable Research Centre in Kruishoutem (PCG): a standard ISO 02 flat fan nozzle (at 200 l/ha), an ISO 04 twin air inclusion nozzle (at 800 l/ha), an ISO 03 drift reducing nozzle, an air injection nozzle (Airjet,) droplegs in combination with an ISO 03 drift reducing nozzle and an ISO 03 air inclusion nozzle (all at 400 l/ha). Best biological control of the aphids and spray distribution was found for the twin air inclusion nozzle, the air inclusion nozzle and the airjet-system. These are all drift reducing techniques because of their coarse droplet size spectrum or the effect of air support which makes the droplets faster. Both effects improve crop penetration. No added value was found for the droplegs for this type of spray treatments. Fine droplets, produced by a standard flat fan, did not give good results on biological control or penetration into the crop.     

Anther culture in Brussels sprouts (Brassica oleracea var. gemmifera)

In Brussels sprouts, yields of up to 357 embryos per 100 anthers cultured were obtained using a thermal shock treatment of 16 h at 35°C at the start of the culture period. Treatments of 48 h at 35°C and 14 days at 30°C gave no embryos. The F₁ hybrid cv. Gower consistently gave higher embryo yields than the F₁ hybrid cv. Nym, the differences being 3 to 10-fold. Differences in embryo yield of 3-fold or less were usually not statistically significant because of great variation within a treatment. This variation was less with donor plants raised in a growth room than with those raised in a glasshouse, where temperature and light intensity could not be so accurately controlled. From 842 embryos cultured, 270 plants were regenerated, mostly via hypocotyl explants, which developed from the anther-derived embryos. Most of the regenerants were haploid or diploid, with a few of higher ploidy.     

The inheritance of node number and rate of node production in Brussels sprouts

Summary The total vegetative node number, rate of node production and number of sprouts over 13 mm diameter were recorded for 10 F₁ Brussels sprout cultivars and 45 progenies derived by intercrossing and selfing them. Significant differences, resulting from additive gene action, were found between the 10 cultivars and between their progenies for both characters. For total node number there was also evidence of dominant gene action. Total node number and rate of node production were closely correlated as were total node number and the number of harvested sprouts. The factors causing differences in rate of node production are indicated and the relationship of this character to other Brussels sprout yield components is outlined.     

Variations in response to high temperature treatments in anther culture of Brussels sprouts

The level, time of application and duration of the high temperature treatment necessary for embryo production from Brussels sprouts anther culture were examined. The effects of 29, 32, 35, and 38°C given for 24 h immediately following removal of the anthers from the bud, were tested on different cultivars, on different plants within the cultivars and on different occasions for each plant. Most embryos were produced following 32 and 35°C, very few following 30°C and none following 38°C. Although there was a tendency for some cultivars to respond better to one or other of the two more favourable temperatures, this varied considerably between individual plants. Plant to plant variation was also seen in the overall level of the response, although responsiveness tended to decline with successive samplings of the same plant. Experiments with cultivars Hal and Gower suggested that high temperature was required for at least 12 h after anther removal, but beyond that time the optimum period varied from plant to plant. If the excised anthers were held at 25°C for 16 h or more with Hal or 24 h or more with Gower before being exposed to the high temperature treatment, embrogenesis tended to be reduced. It is suggested that apparent non-responsiveness in anther culture may result to a large extent from the specific conditions that are used during the anther culture process.     

The effects of topping and plant population on dry matter synthesis and distribution in Brussels sprouts

The effects of topping at different dates, and of different plant populations on dry-matter production and distribution in Brussels sprouts were studied. Total dry-matter production per unit area was unaffected by either topping or density. Leaf area was decreased by topping, resulting in a temporary increase in net assimilation rate. Topping resulted in a redistribution of dry matter; that which would have formed new stem and leaf tissue was directed into sprout production. Increasing plant density did not affect the distribution of dry matter but increased the number of smaller sprouts. The apparent optimum plant spacing in this series was 21×21 in (53×53 cm). At maturity assimilation approximately balances respiration.     

The Effect of Ethylene on Quantitative and Qualitative Aspects of Respiration During the Breaking of Dormancy of Spergula arvensis L. Seeds

The effect of ethylene on quantitative and qualitative aspectsof respiration in Spergula arvensis L. seeds was studied. Oxygenconsumption and CO₂ evolution from seeds increased 60 h afteraddition of ethylene to the dry seed; these increases were consideredto be a function of the number of seeds that were germination,rather than a direct effect of ethylene. The respiratory quotient(RQ) on day 1 (0.5) was lower than on subsequent days, indicatingan absence of anaerobic processes in the early stages of germinationand the use of a different respiratory substrate to that oxidizedon days 2–4. Measurements of C₄/C₁ ratios showed thatethylene did not break dormancy by initiating a switch fromthe Embden-Meyerhof-Parnas pathway (EMPP) to the pentose phosphatepathway (PPP). On the contrary, some evidence was obtained fora switch from the PPP to the EMPP after 3–6 h in pre-imbibedand non pre-imbibed seeds treated with ethylene. Spergula arvensis L., seed germination, ethylene, respiration, Embden-Meyerhof-Parnas pathway, pentose phosphate pathway, respiratory quotient     

Distribution of elemental interactions in Brussels sprouts plants,under the Treated Municipal Wastewater

Abstract

The distribution of the macro, micronutrients and heavy metal interactions in the various plant parts (roots, leaf, and sprout) of Brassica oleracea var. gemmifera (Brussels sprouts), was investigated in a greenhouse experiment of randomized block design, in Agrinion, Greece. The statistical design included two variables: (i) Treated Municipal Wastewater (TMWW), and (ii) fresh irrigation well water (control). The analytical data of plant and soil samples collected were processed statistically by means of regression analysis, ANOVA and t-test, using an SPSS package. The ultimate goal of the experiment was to establish a scientific basis for the safe re-use of TMWW in the irrigation of Brussels sprouts, and possibly of all vegetables, with least accumulation of heavy metals in the sprouts.     

马铃薯-大豆、玉米-大豆邻作对大豆田主要刺吸式害虫以及其他害虫的种群动态影响

【目的】大豆蚜Aphis glycines(Matsumura)是危害我国大豆产量的重要刺吸式害虫,茄无网蚜Acyrthosiphon solani(Kaltenbach)是近年来在大豆田发生逐渐呈上升趋势的刺吸式害虫,蚜虫的发生动态严重影响大豆的产量和品质,本试验调查了马铃薯-大豆、玉米-大豆邻作种植模式对大豆田刺吸式害虫及其他主要害虫的种群动态的影响,为精准使用农药防控蚜虫提供依据。【方法】采用系统调查的方法,研究大豆田刺吸式害虫以及天敌的种群动态,在哈尔滨香坊农场进行马铃薯-大豆、大豆-玉米邻作的种植模式,对其大豆田中大豆蚜、茄无网蚜等刺吸式口器的害虫及天敌动态发生数量进行调查。【结果】2014年与2015年玉米-大豆、马铃薯-大豆种植模式的大豆田中的大豆蚜数量明显低于对照田,2014年玉米-大豆差异更显著,2015年马铃薯-大豆差异性显著。2014年与2015年玉米-大豆、马铃薯-大豆邻作种植模式的大豆田中的茄无网蚜数量显著低于对照田。而2014年8月温度低于2015年虫量相对高于2015年,虫量高时天敌总群动态也相对较高,达到调控作用。【结论】玉米-大豆、马铃薯-大豆邻作种植模式能够起到减少大豆蚜和茄无网蚜的为害的作用,并能够减少农药的使用量。     

Quantitative determination of intact glucosinolates in broccoli, broccoli sprouts, Brussels sprouts, and cauliflower by high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry

Many methods have been proposed to analyze glucosinolates, a class of phytochemicals whose breakdown products are thought to be responsible for an improvement in health; however, few are quantitative and many are time consuming. A selective and sensitive quantitative method for direct determination of intact glucosinolates was developed using liquid chromatography coupled to electrospray ionization tandem mass spectrometry with selected reaction monitoring detection. Detection limits for glucoiberin, sinigrin, progoitrin, glucoerucin, and glucotropaeolin were 1.75, 1.38, 1.36, 0.6, and 0.63 pmol, respectively. Intraassay precision of the method was within 10% for each compound. The method was successfully applied to quantify 10 individual glucosinolates in broccoli, broccoli sprouts, Brussels sprouts, and cauliflower. The advantage of the proposed method includes analysis of individual intact glucosinolates rather than the conversion to desulfoglucosinolates, an increased selectivity through the use of mass spectrometry, and a 10-fold improvement in detection sensitivity over conventionally used HPLC techniques.     

Performance of recombinant inbred lines in Brussels sprouts (Brassica oleracea var. gemmifera)

Summary Performance of a random array of recombinant inbred lines derived by single seed descent from five different source populations of Brussels sprouts (Brassica oleracea var. gemmifera) is presented. A total of 2,356 lines were tested in trials during 1985 and 1986. Three of the source populations were derived from double crosses between F₁ hybrids. These hybrids show a considerable heterotic advantage over their inbred parents for the most important agronomic traits. The recombinant inbred lines performed, on average, less well than the parental inbred material, indicating that additive x additive genie interactions may make a significant contribution to the performance of current inbred material. Nevertheless, the very large variation among the recombinant inbred lines permitted many lines to be identified which outperformed the best parental inbred for all traits. Two lines outperformed the reference F₁ hybrid, Gower, for an index that included marketable yield and quality. Consideration was also given to the dangers of misinterpreting phenotypically based proportions. Accordingly, response equations were used to ascertain the real genetic progress that was made. Advance seemed small when compared with the large heterotic effect, which is consistent with the segregation of a large number of loci. The distribution of the recombinant inbred lines was compared to predictions made from early generation trials. There was broad agreement but significant discrepancies existed which, it is suggested, may arise from the effects of genotype-environment interactions.