Desiccation and storage behavior of bay laurel (Laurus nobilis L.) seeds

The effect of seed moisture content (m.c.) and seed storage conditions of bay laurel (Laurus nobilis L.) was investigated in relation to seed viability. In the first experiment, the effect of drying rate on seed moisture and seed germination was investigated. Fresh seeds, with their original moisture content displayed a germination percentage of 55.1%. When the seed moisture content was reduced by 2.0% in an oven, the germination percentage rose to 81.0%. When the seed moisture content was reduced even more by using the same method, the germination percentages decreased dramatically. Reducing the seed moisture content to 28.7 and 23.5% by drying the seeds in alternating room conditions resulted in an increase of seed germinability to 84.3 and 90.9%, respectively. The drying of the seeds for 45, 60 and 75 days reduced their seed germination to 66.8, 49.4 and 48.0%, respectively. Reducing seed moisture content below 15.0% resulted in practically nullifying seed germinability. The fact that bay laurel seeds cannot retain their germinability at lower moisture contents demonstrates that it is a species with recalcitrant seeds. In the second experiment, moist and dry storage conditions were tested under different temperatures and moisture contents. The storage experiment showed that the most effective way of conserving the bay laurel seeds is moist storage at 0 ± 1°C for 4 months without previous drying of the seeds.     

Relating germination dynamics of Melampsora pinitorqua teliospores to temperature and rainfall during overwintering

The influence of overwintering conditions on the dynamics of Melampsora pinitorqua teliospore germination in spring was assessed in the Landes forest (south-western France), over 3 years. January accumulated temperature was the variable most strongly linked to the date of optimum germinability (JDOG), in a negative direction. A linear regression using accumulated degree-days and number of rainy days in January accounted for nearly 70% of overall variation in JDOG. Accumulated temperature from October 1 and January 1 to the date of optimum germinability showed lower coefficients of variation than JDOG. The best predictions of JDOG in an independent data set were obtained by using the accumulated temperature from January 1 to the date of optimum germinability or a linear regression based on accumulated temperature in January. The mean square root error of prediction was approximately 5 days. The ecological significance of the temperature-dependent model is discussed in relation to the synchronization of rust and pine phenologies.     

Oospore viability and variation in zoospore and hyphal tip derivatives of the hybrid alder Phytophthoras

Oospore viability, oospore germinability, and phenotypic variation among zoospore and hyphal tip derivatives of the standard and natural variant types of the hybrid alder Phytophthoras were investigated. Oospore viability in the standard hybrid, estimated by the tetrazolium bromide method, was low (≈ 31–36%). No germination was observed in more than 4000 oospores, although germination did occur in the Phytophthora cactorum, Phytophthora citricola and Phytophthora cambivora controls. This is consistent with the known meiotic irregularities in this hybrid. Mean oospore viabilities in the natural variants were significantly different (p < 0.001), ranging from approximately 24% in the UK variant to approximately 75% in the Dutch variant. Again, no oospore germination was observed. Zoospore and hyphal tip derivatives of the standard hybrid and of the Swedish and Dutch variants resembled the ‘parent’ isolate in phenotype. The derivatives of the German and UK variants, however, often differed from the parent type. Those of the UK variant were extremely and continuously variable in colony patterns, growth rates, temperature–growth relationships and fertility levels. Although these results do not support the view that the natural variants arise as genetic breakdown products of the standard hybrid, this possibility cannot yet be excluded. The apparent inviability of the oospores suggests that the mycelium and zoospores are mainly responsible for the survival and spread of the alder Phytophthoras in the field.     

Effect of increasing distance fromAcacia nilotica trees on wheat yield

Planting trees in the cultivated fields of Pakistan is a controversial topic between foresters and agriculturists. Some farmers believe that trees significantly reduce their crop yields; therefore they avoid planting trees in their fields. On the other hand, many foresters claim trees are beneficial for crops. This study was conducted to determine the influence of boundary trees (Acacia nilotica) on the growth and yield of associated wheat crops under irrigated conditions in Punjab, Pakistan. Results indicate that close proximity to trees adversely affected tillers/m², weight/1000 grain and the grain yield of wheat planted up to a distance of 8.5 m from the trees. Plant height and grains/spike were least affected. In general, the growth and yield of wheat improved as distance from the tree increased. Tree size did not affect wheat height, tillers/m², grains/spike or weight/1000 grain. The grain yields were slightly lower near the largest trees (50–54.9 cm DBH trees).     

Destruction of Fraxinus angustifolia and Fraxinus ornus seeds under storage conditions caused by Epicoccum nigrum

During the period of seed storage in 2019, stored Fraxinus angustifolia and F. ornus seeds showed signs of infection and fungus Epicoccum nigrum was isolated from mould and necrotic lesions on the seeds. In order to confirm the pathogenicity of E. nigrum towards F. angustifolia and F. ornus seeds, an experiment that included inoculation of seeds with E. nigrum and the assessment of germinability was performed. The inoculation with E. nigrum strain caused mould to around 20% of F. angustifolia and 58% of F. ornus, necrotic lesions to 96% of F. angustifolia and 92% of F. ornus, and decrease in germinability to 95% of F. angustifolia and 97% of F. ornus seeds. This study presented, for the first time, the ability of E. nigrum to cause high infection rates and reduced germinability of the F. angustifolia and F. ornus stored seeds. The transmission routes and possibilities for preventive strategies were discussed.     

The influence of coppiced teak (Tectona grandis L.F.) regrowth and roots on intercropped maize (Zea mays L.)

Trenching and shoot removal showed the relative influences of living roots and the canopy cast by teak (Tectona grandis L.F.) coppice regrowth on the growth and yield of interplanted maize (Zea mays L.). Teak and maize were planted at 1.8 × 1.8 m and 0.3 × 1.8 m spacing respectively.Competition for light started about four weeks after planting and caused etiolated height growth of maize. When combined with root competition it caused stunted growth. Shading also substantially reduced total dry matter production, grain yield, number of cobs per plant, average cob weight, and weight of grains per cob of maize (P<0.01). Living teak roots alone did not have a significant effect (P>0.05) on maize height growth, total dry matter production, grain yield, number of cobs per plant,average cob weight and weight of grains per cob. However, combined with shading, living roots of teak appreciably reduced total dry matter yield and average cob weight of maize (P<0.01).     

Observations on some Italian provenances of Melampsora populnea

In some Italian provenances of Melampsora populnea on Populus tremula from mountain zones, the presence of Melampsora pinitorqua was tested through teliospore germinability tests and sub-sequent basidiospore inoculations. In this study the risk of twist rust epidemics in new planta-tions is discussed.     

Tocopherols,tocotrienols and fatty acids as indicators of natural ageing in Pinus sylvestris seeds

Abstract

During long-term storage, Scots pine (Pinus sylvestris L.) seeds are susceptible to ageing, leading to declined vigour and poor germinability. To characterize biochemical changes associated with this ageing, vitamin E and fatty acid compositions of Scots pine seeds stored for 3–31 years were analysed. The seeds contained seven homologues of the vitamin E family: α-, β-, δ- and γ-tocopherols (T) and α-, δ- and γ-tocotrienol (T3). The major tocopherol was γ-T, constituting on average 62.1% of total vitamin E. Total vitamin E concentration was markedly lower in older seeds, e.g. 21-year-old seeds contained 52% less vitamin E than the reference for high-quality seed. The α-T concentration was affected the most by seed age, whereas the γ-T concentration decreased more gradually and the concentrations of the other E vitamers seemed to remain relatively constant during natural ageing. Ageing also induced changes in the fatty acid composition of the seeds, e.g. a 29.6% reduction in the unsaturation/saturation ratio. These biochemical changes were associated with decreased germinability and increased electrolyte leakage.     

Efficacy of Clausena anisata and Plectranthus glandulosus leaf powder against Prostephanus truncatus (Coleoptera: Bostrichidae) and two strains of Sitophilus zeamais (Coleoptera: Curculionidae) on maize

Powdered leaves of Clausena anisata and Plectranthus glandulosus were evaluated on Cameroonian and German strains of Sitophilus zeamais and Prostephanus truncatus for their insecticidal activities, the effects on progeny production, grain damage and population increase by admixing powders and maize grains. The two powders caused significant mortality of the three insects with P. glandulosus being far more effective than C. anisata. P. truncatus was less susceptible to P. glandulosus powder compared with the two strains of S. zeamais. The German strain (LD₅₀ = 2.75 g/100 g grain) of S. zeamais was less susceptible to P. glandulosus powder than the Cameroonian strain (LD₅₀ = 1.86 g/100 g grain). P. glandulosus unlike C. anisata powder, considerably reduced grain damage, progeny production and population increase. This study shows that there is a great potential for the powder of P. glandulosus as a promising grain protectant for integration within the subsistence farming systems of sub-saharan Africa.     

Field tests on biological control of Heterobasidion annosum by Phaeotheca dimorphospora in comparison with Phlebiopsis gigantea

In field tests conducted on freshly cut red pine (Pinus resinosa) logs, the antagonistic fungus Phaeotheca dimorphospora formulated as pre‐colonized rye grains reduced colonization of wood tissue by Heterobasidion annosum to less than 2% over the 2 months following inoculation. However, compared to controls, a water suspension of P. dimorphospora did not reduce the infection, but rather promoted colonization by H. annosum after a 2‐month exposure. Production of antifungal metabolites by P. dimorphospora in the rye grains and better colonization of the logs by the antagonist were observed with the rye grain formulation. In this field test, the most effective treatment to control H. annosum was the application of an oidial suspension of Phlebiopsis gigantea. This fungus completely inhibited colonization by H. annosum mostly by rapid colonization of wood tissue. All treatments with P. gigantea, P. dimorphospora and rye grains influenced the naturally occurring mycoflora. The most important species composing this mycoflora were Hormonema sp., Mortierella spp., Mucor hiemalis f. hiemalis, Nectria sp., Pesotum sp., P. gigantea, Tympanis spp., Trichoderma spp. and an unknown basidiomycete.     

不同含水量球孢白僵菌孢子抗逆性研究

影响球孢白僵菌（Ｂｅａｕｖｅｒｉａｂａｓｉａｎａ（Ｂａｌｓ．）Ｖｕｉｌ．）的贮藏的环境稳定因素主要为环境温度及紫外光。孢子含水量高低影响虫生真菌菌株的耐热性,金龟子绿僵菌（Ｍｅｔａｒｈｉｚｉｕｍａｎｉｓｏｐｌａｅ（Ｓｏｒｏ．））在３０ｍｉｎ内的半致死...     

Comparative efficacy of NeemAzal and local botanicals derived from <Emphasis Type="Italic">Azadirachta indica</Emphasis> and <Emphasis Type="Italic">Plectranthus glandulosus</Emphasis> against <Emphasis Type="Italic">Sitophilus zeamais</Emphasis> on maize

The efficacy of NeemAzal powder, two local neem (Azadirachta indica ) products [neem seed powder (NSP) and neem seed oil (NSO)], as well as a local Lamiaceae, Plectranthus glandulosus leaf powder, applied at four different rates for the control of Sitophilus zeamais was determined. Mortality was recorded 1, 3, 7 and 14 days after S. zeamais infestation, followed by the determination of F₁ progeny production. Grain damage, population increase and grain germination were assessed for treated grains that were stored for 4 months. Grains treated with P. glandulosus powder and NSP had relatively low mortality (5.0–22.5%) after 3 days whereas NeemAzal and NSO had higher mortality (55.0–98.8%). Maximum mortality of 99, 100, 96 and 74% were achieved for NeemAzal (12 g/kg after 14 days), NSO (4 ml/kg after 7 days), NSP (40 g/kg after 14 days) and P. glandulosus powder (40 g/kg, after 14 days), respectively. In the same order, 7-day LC₅₀ values were 0.02 g/kg, 1.46 ml/kg, 12.44 g/kg and 28.9 g/kg. The three neem products greatly reduced progeny emergence, while P. glandulosus powder was less effective. NeemAzal protected the grains against S. zeamais damage better than the local neem products, which in turn provided far better grain protection against the weevil damage than P. glandulosus powder. NeemAzal was superior to the local neem products in grain protection against germination loss, with P. glandulosus being the least effective. NeemAzal and NSO had sufficient efficacy to be a component of an integrated management package for S. zeamais.     

Pirimiphosmethyl und Malathion als Getreideschutzmittel gegen vorratsschädliche Insekten im Irak

Emulsifiable formulation of pirimiphos-methyl and malathion were applied to wheat, barley and maize at rates of 5, 10 and 15 ppm. The treated grains were stored under warehouse storage conditions and the residual effeciency of both insecticides on treated grains were estimated at zero-time, 2, 4, 6 and 8 weeks by using of bioassay tests on 4th instar larvae ofTrogoderma granarium (Everts) and 14-day-old adults ofTribolium confusum (Duval). Results indicated that the residual effeciency of the insecticides used varied according to the storage period, sort of stored grains, type and rate of insecticide applied. The insect species was also influenced. Pirimiphos-methyl residues seemed to be more persistent than that of malathion on all treated grains. The effeciency of the insecticidal deposit varied between the different cereals being less on barley than on maize and this than on wheat. BesidesTribolium confusum appeared to be more susceptible to both insecticides thanTrogoderma granarium. Pirimiphos-methyl proved to be suitable substitute to malathion as grain protectant against possible malathionresistant strains of stored grain insects.     

Field evidence of roof rat (Rattus rattus) faecal contamination of barley grain stored in silos in the Czech Republic

This study represents the first European report of a risk assessment for the contamination of grain by roof rats’ (Rattus rattus L.) faeces in silo structures that have traditionally been considered to be rodent-contaminant proof. In this work, we estimated the rate and magnitude of grain and grain transport silo technology contamination by faeces of R. rattus and identified the routes of entry of rodent faeces into grain stored in silos. We also compared the sizes of rat faeces and stored barley grains to determine whether they could easily be separated using sieves. We found that roof rats were able to heavily contaminate grain surfaces and conveyor belts with faecal deposits during a 3-week observation period. The average contamination rate was 6.90 ± 0.92 faeces/m² (range 0–26 faeces/m²) for grain surfaces and 34.80 ± 8.03 faeces/m² (range 8–87 faeces/m²) for conveyor belts. The size measurements (length, width and surface area) of rat faeces and barley grains showed their high similarity; these results therefore indicate that the physical separation of the two materials using sieves will be problematic.     

Resistance of tropical maize genotypes to the larger grain borer

Post-harvest losses caused by the larger grain borer (LGB, Prostephanus truncatus) aggravate food insecurity among small-scale farmers. Host plant resistance is a method of LGB control which should be prioritized in order to reduce these losses. The objective of this study was to assess maize resistance to the larger grain borer and recognize some potential causes of resistance. One hundred and sixty-three (163) genotypes were tested; these included 85 hybrids, 2 checks, 6 open pollinate varieties, and 70 landraces, among them gene bank accessions. Grain biochemical content, (protein, oil and starch) and insect resistance parameters, (percentage grain damage, weight loss, flour weight, and number of emerged insects) were measured. There were significant differences (P < 0.001) among the genotypes for all the traits measured except number of insects. The most resistant hybrids were CKPH08024, CKPH08009, CKPH08012, CKPH08014, CKP08033, CKPH08026, CKPH08014, and CKPH08003. The most resistant landrace accessions were BRAZ 2451, GUAT 1162, BRAZ 2100, and GUAN 36. The percentage weight loss was found to be the most important resistance trait for discriminating among genotypes for it had the largest canonical coefficient. Protein content had higher contribution to variation in resistance to the larger grain borer and this probably contributed to the grain hardness which is a putative trait of resistance to storage pests. The LGB-resistant germplasm could be used for the development of an integrated pest-management program against the LGB.     

Capture of stored-grain Coleoptera with WB Probe II Trap: influence of grain type

The commercially available trap WB Probe II Trap have been used in laboratory to monitor insects activity in grains at 24±1°C and 70±5% r.h.. The major coleopteran pests of cereals in Italy,Oryzaephilus surinamensis (L.),Rhyzopertha dominica (F.),Sitophilus oryzae (L.) andTribolium castaneum (Herbst), were added to the grain at about 0.9 insect per kg. Two tests were prepared: in the testA insect activity was observed in spring wheatTriticum aestivum, L.; in the testB were compared in oat grainAvena sativa L., spring wheatTriticum aestivum L. and maize grainZea mays L. Significant differences in the numbers of insects collected by the traps were observed, both when compared across traps and cereal types. In all cereals considered traps trapped moreS. oryzae thanT. castaneum andO. surinamenis; the species less trapped wereR. dominica.     

Temporal and spatial variation of pollen yield in natural populations of Pinus roxburghii

Male components of the reproduction process in Pinus roxburghii were investigated for their variation in time and space as well as pollination,viz.flowering phenology,pollen production variability and pollen dispersal,for five successive years at two different locations (at the lower and higher elevations).The study reveals that elevation and the hour of the day are the main determinants of anthesis and microsporangium dehiscence,because both are related to temperature and humidity.The receptivity of ovulate cone strobili or female strobili occurred earlier at the lower elevation than at the higher elevation,with a longer receptivity period in the latter case.The phenology of male and female cones varied significantly between years and elevations.The determinations of pollen yield considered various sources of variability,i.e.,the number of pollen strobili per branch,strobili per tree,microsporangia per tree and pollen grains per tree.Each of these parameters revealed significant year-to-year and elevation effects.Year-to-year variation in the production of pollen cone and pollen grains with mass production after a three-year period revealed a three-year cycle of masting in pollen production in P.roxburghii.The pollen dispersal decreased quickly with distance from the pollen source.As a consequence,a distance of 600 m was proposed as a minimum to prevent contamination by pollen in the management of seed orchards.The results ultimately suggest that the ample production of pollen grains per tree along with flowering synchrony and long dispersal of pollen grains results in homogeneity in large populations.     

On-line determination of the grain angle using ellipse analysis of the laser light scattering pattern image

Under fixed cutting conditions, the surface finish roughness is correlated to the grain angle. However, the means of determining the grain angle automatically and accurately is still a challenge for on-line control of the router. It is therefore necessary to develop a new technology to determine the grain angle accurately and automatically. In this research, a laser light scattering pattern was used to accurately determine the grain angle. The light scattering pattern image was a quasi-ellipse caused by the grain direction and tracheid effect. A new modified Hough transform ellipse analysis technology was adopted to determine the ellipse parameters that could be used to determine the grain angle. The results indicated that the measured grain angle using the method proposed here was accurate and effective. The measured grain angle coincided with the real grain angle. There was an insignificant difference between the measured grain angle of Japanese beech (Fagus crenata blume) and that of sugi (Cryptomeria japonica D.Don) under two machining conditions that gave planed or sawn finishes. However, the accuracy of the measured grain angle of sugi was better than that of Japanese beech for the planed finish, the accuracy of the measured grain angle of Japanese beech was better than that of sugi for the sawn finish, and the accuracy of the measured grain angle for planed samples was better than that for sawn samples of both sugi and Japanese beech.     

A contribution to the pollen morphology for arboreal type of caesalpinioideae in Korea

The pollen morphology of 7 taxa of three genera of the subfamily Caesalpinioideae in Korea was investigated by light microscope (LM) and scanning electron microscope (SEM). The pollen grains of this subfamily are monads, prolate spheroidal or subprolate, and trizonocolporate. Sculpture pattern is reticulate or perforate. Based on sculpture pattern, colpus width and grain shape at equatorial view, 4 major pollen types of the subfamily are discernible;Caesalpinia, Cercis, Gleditsia I, andGleditsia II. This study was supported by Korean Academic Promotion Foundation. During this study, Botanic Garden of Kyoto University, Japan, Anmyondo Arboretum and Dr. Byongsoo Kang at Dongkuk Univ., Korea provided materials and informations which are greatly appreciated.     

Insecticidal effects of the powdery formulation based on clay and essential oil from the leaves of <Emphasis Type="Italic">Clausena anisata</Emphasis> (Willd.) J. D. Hook ex. Benth. (Rutaceae) against <Emphasis Type="Italic">Acanthoscelides obtectus</Emphasis> (Say) (Coleoptera: Bruchidae)

The bioefficacies of essential oil and aromatized clay powder based on the mixture of clay and essential oil extracted from Clausena anisata were evaluated for their insecticidal activities and their effects on progeny production of Acanthoscelides obtectus. Contact toxicity assayed by coating on bean grains showed that these chemicals caused significant mortality of the test insect. Beetle mortality was dose dependant and after 2-day exposure the aromatized clay powder was more toxic (LD₅₀ = 0.069 μl/g grain) than the pure essential oil (LD₅₀ = 0.081 μl/g grain). There was, however, a highly significant loss of toxicity after 24 and 36 h following treatment with essential oil and aromatized powder, respectively. Both aromatized clay powder and pure essential oil considerably reduced the F₁ progeny insect production. The essential oil evoked moderated repellent action and high fumigant toxicity (LC₅₀ = 0.093 μl/cm³) against adults of A. obtectus. These results suggest that the clay powder could be used to stabilize the essential oil to increase its efficacy for use as an alternative to synthetic insecticides.