bluuebunny/crossref_metadata_2025 huggingface dataset:
Selection of Barley Lines for Drought Tolerance in Low‐Rainfall Areas
Authors: Shakhatreh Y. , Kafawin O. , Ceccarelli S. , Saoub H.
Published: March 2003

An experiment was conducted at five locations in Jordan (Khanasri, annual rainfall 150 mm; Ramtha, 225 mm; Muwaqar, 150 mm; Rabba, 350 mm; Ghweer, 250 mm) during the 1996/1997 growing season, to evaluate the yield performance and some agronomic traits of 84 barley breeding lines and three long‐term checks (Zanbaka, Arta and Klaxon) for drought tolerance. An α‐lattice design with two replications and six incomplete blocks for each replication was used. Genotype 6 (WI2291/Tadmor) was found to be superior in grain yield, especially compared to the best check (Arta) at the two wettest locations (Rabba and Ghweer). Genotype 21 (Mo.B1337/WI2291/5/Emir/Sb//CM67/3/F8‐HB‐854‐23/121//148‐221/4/CI 08887/CI05761) out‐yielded the best check (Arta) at the driest location (Khanasri), while genotype 61 (Salmas/Arabia Aswad) produced a higher grain yield than the best check (Zanbaka) at Ramtha. The correlations amongst grain yield, biological yield, straw yield, plant height and harvest index were always significant and positive regardless of the location. The correlations amongst days to heading, days to maturity and grain yield were significant at the two driest locations only. This suggests that different phonologies are required to maximize grain yield in wet and dry environments. Also, the relationship between grain yield and the length of grain‐filling period was positive in the wettest location (Rabba), negative in the driest (Khanasri) and not significant at the two intermediate locations. These results emphasize the importance of selection in the target environment and the need to develop early‐maturing genotypes as a way of withstanding drought and high temperatures during the grain‐filling period. A high and negative correlation coefficient was found between the drought susceptibility index and grain yield at the driest site, whereas at the wettest site the correlation coefficient was lower and in some cases positive, indicating the existence of traits that are desirable under drought and undesirable under favourable conditions.
Carbon Isotope Discrimination and Grain Yield Variations among Tetraploid Wheat Species Cultivated under Contrasting Precipitation Regimes
Authors: Merah O. , Deléens E. , Al Hakimi A. , Monneveux P.
Published: March 2003

Nineteen accessions belonging to six tetraploid wheat species were evaluated and compared for carbon isotope discrimination and grain yield during two successive cropping seasons (1995 and 1996) under Mediterranean rainfed conditions. The two seasons differed markedly in precipitation regime. A wide variation for the measured traits was observed among the 19 accessions for carbon isotope discrimination and grain yield in both years. Significant differences were also noted between species accessions for Δ and grain yield. In both years, Triticum timopheevi (AG genome) showed lower Δ values than the other tetraploid species (all carrying the AB genome). Positive correlations were observed between Δ and grain yield in both years. The use of carbon isotope discrimination as an indirect selection criterion for yield under stress and the potential benefits of some alien tetraploid species in improving drought tolerance in durum wheat are discussed.
Varietal Differences in Development of Maize (Zea mays L.) Seedlings on Compacted Soils
Authors: Soyelu L. O. , Ajayi S. A. , Aluko O. B. , Fakorede M. A. B.
Published: March 2003

Differences among open‐pollinated tropical maize (Zea mays L.) varieties in seedling development and establishment on compacted soils were studied. Soil dry density was used as an index of compaction. Three soil compaction levels and 12 traits associated with development and establishment of maize seedlings were investigated. A control (without compaction) was also included. Varietal differences were observed for most traits measured. Genetic differences for seedling development on compacted soil were detected. Varietal differences contributed about three times the contribution of compaction to total variability in the traits. Better seedling development and performance were obtained in moderately compacted soil than in the control. Shoot length, shoot dry weight and per cent dry matter in roots were good indicators of the tolerance of maize seedlings to compaction. A physiological strategy for maize seedling establishment on compacted soil was proposed. The implications of the results for seed testing were also highlighted. It was concluded that consideration should be given to the genotype of maize destined for use in ecologies prone to high soil densities. All varieties of maize grown in an agroecological zone could be screened to identify genotypes tolerant of higher soil densities. The seeds could then be multiplied and distributed to farmers.
Effects of Interactions of Moisture Regime and Nutrient Addition on Nodulation and Carbon Partitioning in Two Cultivars of Bean (Phaseolus vulgaris L.)
Authors: Boutraa T. , Sanders F. E.
Published: March 2003

Major limitations of bean (Phaseolus vulgaris L.) production in arid and semiarid regions are lack of moisture and low soil fertility. An experiment was conducted to determine the effects of soil moisture and N : P : K (20 : 10 : 10) fertilizer on root and shoot growth of two cultivars of bean: cv. Carioca, an indeterminate Brazilian landrace, and cv. Prince, a determinate cultivar grown in Europe. Carioca appears generally stress‐tolerant while Prince is intolerant. Seedlings were grown in pots of non‐sterile soil at 30, 60 or 90 % field capacity (FC), and given 0, 0.1 or 1 g (kg soil)–1 of compound fertilizer. The soil contained a population of effective Rhizobium. Growth of both cultivars was greatest in the high moisture and high nutrient treatments. Root fractions were highest at low nutrient supply; the effect of water was not significant. Leaf fraction decreased as root fraction increased. Numbers of nodules were highest at high and intermediate moisture when no fertilizer was applied. Numbers were lowest at 30 % FC and at the highest fertilizer rate. Masses of nodules and fractions followed the same pattern. Decreasing water regime reduced the relative growth rate (RGR) of Prince, while Carioca maintained high RGR at unfavourable conditions of water and nutrients. Net assimilation rates (NAR) were unaffected by nutrient addition, and reduced by low moisture regime. Water use efficiencies (WUEs) were reduced by water stress but increased by nutrient deficiency. The water utilization for dry matter production was optimal at 60 % FC.
Effect of Overseeding Forages into Alfalfa on Alfalfa Weevil, Forage Yield and Quality
Authors: Putnam D. H. , Long R. , Reed B. A. , Williams W. A.
Published: March 2003

Many alfalfa (Medicago sativa L.) fields are sprayed each year with insecticides to control Egyptian alfalfa weevil (Hypera brunneipennis) and the alfalfa weevil (Hypera postica). Overseeding various species of legumes and grasses into established alfalfa has been proposed as a method to mitigate weevil damage without insecticides. Established fields of alfalfa were overseeded with legumes and grasses in randomized complete block designs in three years of study in a Mediterranean climate in the Sacramento Valley of California, USA. Several overseeding practices maintained or increased yields compared with the insecticide‐sprayed treatment. Overseeding increased or maintained forage yield, eliminating the need for insecticides. However, overseeding did not prevent weevil damage to alfalfa. Overseeding is best used to extend the life of alfalfa stands in the final year of production, since overseeding can thin alfalfa stands. Market acceptance for mixed‐species hay and harvest management of overseeded forages are the most important limitations to overseeding practices.
Inter‐relationships Amongst Grain Characteristics, Grain‐Filling Parameters and Rice (Oryza sativa L.) Milling Quality
Authors: Jongkaewwattana S. , Geng S.
Published: March 2003

Resistance to breakage is a desirable trait of the rice kernel. Many factors, such as the genetics of the cultivar, the plant growth environment and the conditions of the milling process, will affect kernel breakage. Although many papers have discussed the factors that may affect and improve rice milling quality, few have related the grain‐filling process to head rice, the unbroken polished kernels obtained after milling. The objectives of this paper were: (i) to characterize the interrelationships amongst grain filling and grain structural characteristics; (ii) to determine whether the grain‐filling process and grain characteristics affect head rice, and (iii) to suggest a pathway through which grain characteristics can influence head rice recovery. An analysis of the interrelationships amongst all grain characteristics suggested that variables of grain structure (size, volume and per cent hull) have a decisive influence on the grain‐filling process (rate and duration of grain filling). The grain‐filling process will affect final grain traits such as weight and density, which in turn will have a direct impact on head rice. In addition, non‐uniformity, whether expressed in terms of variable grain size and shape or grain filling and maturity, has a detrimental effect on rice milling quality. The implication of these findings is that rice breeders need to pay more attention to selecting plant types that have a high degree of uniformity of grain characteristics on the panicle, and to those traits (such as greater grain size, weight and density) that have a positive impact on yield and milling quality.
Influence of Water Stress on Grain Yield and Vegetative Growth of Two Cultivars of Bean (Phaseolus vulgaris L.)
Authors: Boutraa T. , Sanders F. E.
Published: March 2003

Lack of water during vegetative and/or reproductive growth stages is one of the most limiting factors for bean growth. The purpose of this study was to evaluate the effects of water stress applied during two phenological stages (flowering and pod filling) on growth, yield and yield components. Two genotypes of bean (Phaseolus vulgaris L.) were used in this study, cv. Carioca, an indeterminate Brazilian landrace, and cv. Prince, a determinate cultivar grown in Europe. Carioca appears to be generally stress‐tolerant while Prince is intolerant. Plants were grown in large plastic pots covered with a black plastic sheet to protect the soil from rain and evaporation. The water stress treatments were: control (well‐watered plants), WSFS (water stress during flowering stage) and WSPFS (water stress during pod‐filling stage). Water stress reduced yield and yield components at both flowering and pod‐filling stages. The parameters affected were seed weight, number of seeds per plant and number of pods per plant. Number of seeds per pod and seed weight were not affected. No effects of water stress were detected on harvest index. Time to maturity was slightly prolonged, especially for WSFS. Water stress at both stages resulted in lower accumulated water loss compared to the control plants. Water stress during both phenological stages reduced other growth parameters, the number of trifoliate leaves, stem height, number of main branches and number of nodes on the main stem.
Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts
Authors: Chon S.‐U. , Kim J.‐D.
Published: March 2003

Autotoxicity restricts reseeding of alfalfa (Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments. A series of aqueous extracts from leaves, stems, roots and seeds of alfalfa ‘Vernal’ were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. Extracts at 40 g dry tissue l−1 from alfalfa leaves were 15.4, 17.5 and 28.7 times more toxic to alfalfa root growth than were those from roots, stems and seeds, respectively. A high‐performance liquid chromatography (HPLC) analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compounds depended on the plant parts. In leaf extracts that showed the most inhibitory effect on root growth, the highest amounts of allelochemicals were detected. Among nine phenolic compounds assayed for their phytotoxicity on root growth of alfalfa, coumarin, trans‐cinnamic acid and o‐coumaric acid at 10−3 m were most inhibitory. The type and amount of causative allelochemicals found in alfalfa plant parts were highly correlated with the results of the bioassay, indicating that the autotoxic effects of alfalfa plant parts significantly differed.
Evaluation of Annual Medicago for Upper Midwest Agroecosystems
Authors: De Haan R L. , Sheaffer C. C. , Samac D. A. , Moynihan J. M. , Barnes D. K.
Published: March 2003

Annual Medicago species (medics) have characteristics that may make them a valuable addition to agricultural systems in the Upper Midwest, USA, but few genotypes have been evaluated. The objective of this research was to identify medic germplasm exhibiting traits that are desirable for cultivars intended for multiple uses in the region. Australian annual medic cultivars and plant introductions (PI) representing seven species were evaluated for Phytophthora root rot (Phytophthora medicaginis Hansen et Maxwell) resistance, shade tolerance, growth habit, dry matter accumulation, maturity after 9–10 weeks of growth, and potato leafhopper (Empoasca fabae Harris) yellowing. Medicago polymorpha L. plant introductions PI 197346, PI 459135, and PI 283653 were resistant to Phytophthora root rot. Kelson [Medicago scutellata (L.) Mill.] and PI 419241 [Medicago tornata (L.) Mill.] were tolerant of shade, while M. polymorpha entries Santiago and SA 9032 were intolerant. In growth habit comparisons, PI 419241 and PI 368939 (M. polymorpha) grew less than 11 cm tall, while Kelson and SA 5762 (M. polymorpha) grew at least 27 cm tall. Dry matter production 10–12 weeks after emergence was greatest for PI 197339 (M. polymorpha) and Kelson. At that time, the earliest maturing entries, PI 226517 (M. polymorpha) and Sava (M. scutellata), had begun to senesce, while the latest maturing entry (PI 419241) was still vegetative. Paraponto (Medicago rugosa Desr.) was highly resistant to potato leafhopper yellowing. None of the medic entries evaluated combined all of the desirable traits for Upper Midwest cultivars, but the traits were all present within available germplasms. Plant breeders could develop adapted cultivars by combining favourable traits from several medic genotypes.
Recovery of 15N‐Labelled Urea Applied to Wheat (Triticum aestivum L.) in the Ethiopian Highlands as Affected by P Fertilization
Authors: Gorfu A. , Kühne R. F. , Tanner D. G. , Vlek P. L. G.
Published: March 2003

Soil degradation and depletion of soil nutrients are among the major factors threatening sustainable cereal production in the Ethiopian highlands. Fertilizer use as a means of mitigating nutrient depletion has become widely accepted. The fate of fertilizer nitrogen (N) applied to a semidwarf bread wheat system was determined in microplots receiving 41 kg N ha−1 in the form of urea labelled with 5.617 % atom excess 15N, without and with the application of phosphorus (P) at 20 kg P ha−1. The study was conducted in three different agro‐ecological zones at 2200, 2400 and 2800 m above sea level (masl) (Kulumsa, Asasa and Bekoji, respectively) in the south‐eastern Ethiopian highlands. Yield and yield response to N diminished with elevation, while the response to P increased with elevation, with a significant increase in wheat grain yield observed at Bekoji (2800 masl). N harvest index and N use efficiency improved in response to P application at Asasa (2400 masl). Crop removal accounted for 25–64 and 36–64 % of the applied N without and with P, respectively. The corresponding fractions of 15N recovered in the soil ranged from 2.9 to 3.5 % and from 3.2 to 3.7 %, respectively. Recoveries of applied 15N were 67 and 52 % at Kulumsa and Asasa, but only 25 % at the highest elevation site, Bekoji. Fertilizer P significantly enhanced N recovery at Asasa (60 %) and Bekoji (36 %), but not at Kulumsa, where the soil had a high level of residual P from previous applications. The fraction of 15N recovered in the soil–plant system was rather low at Bekoji. However, the rate of 15N recovery was significantly improved (by 37 %) when fertilizer P was added to the soil. Across all locations, the unaccounted 15N may have been lost primarily through denitrification and volatilization.
Heterosis, sex and breed differences in the fatty acid composition of muscle phospholipids in beef cattle
Authors: Malau‐Aduli A. E. O. , Siebert B. D. , Bottema C. D. K. , Pitchford W. S.
Published: March 2003

Longissimus dorsi muscle tissue was biopsied between the 12th and 13th ribs of 96 purebred Jersey, purebred Limousin and Jersey × Limousin crossbred calves at the age of 9–10 months. Fatty acids of the phospholipid fraction were extracted and analysed for sex and breed differences. Heterosis, additive and maternal variances were estimated. All calves grazed pasture in a single management group and were biopsied from the same anatomical site. Steer calves had significantly higher proportions of the 14 : 0, 14 : 1, 18 : 2, 20 : 3 fatty acids and less of the 16‐di‐methyl‐acetal than heifer calves. Significant breed differences were observed: Limousin calves had the highest proportions of 16 : 0, 24 : 0 and saturated fatty acids (SFA), whereas Jersey×Limousin calves had the most 18 : 0 and elongation index. Dominant effects were evident in the proportions of 16 : 0, 18 : 0, SFA and elongation index. Additive genetic effects were significant in the proportions of 16 : 0, 18 : 0, 18 : 1n‐9, total SFA and desaturation and elongation indices. Combined maternal and additive effects were significant for long chain polyunsaturated fatty acids 18 : 2, 20 : 3 and 20 : 4.
Breed differences and heterosis in triacylglycerol fatty acid composition of bovine adipose tissue
Authors: Malau‐Aduli A. E. O. , Edriss M. A. , Siebert B. D. , Bottema C. D. K. , Pitchford W. S.
Published: March 2003

Subcutaneous adipose tissues were biopsied in purebred Jersey (n=17), purebred Limousin (n=17) and reciprocal F1 Jersey × Limousin crossbred (n=33) calves at the age of 9–10 months. Triacylglycerol fatty acids were extracted and analysed for sex and breed differences. Heterosis, additive and maternal variances were estimated. All calves were pasture‐fed in a single management group and biopsied from the same anatomical site. Heifer calves had significantly higher proportions of palmitoleate, total mono‐unsaturated fatty acids, desaturation index and lower stearate than steer calves. Significant breed differences were observed in that Limousin calves had the highest proportions of palmitate and total saturated fatty acids, whereas Jersey calves had the most palmitoleate and desaturation index. Dominance effects were evident in the proportions of palmitate, stearate, desaturation and elongation enzyme indices due to the observed highly significant heterosis effect. Myristate, palmitate and total saturated fatty acids were considered heritable due to the observed highly significant additive genetic effect.
Investigations on the effect of maternal dietary riboflavin supplementation during gravidity and lactation on riboflavin concentrations in blood, liver, and total body of rat offspring
Authors: Roth‐Maier D. A. , Kettler S. I. , Hirschvogl G. , Kirchgessner M.
Published: March 2003

The present study investigated the effect of various maternal dietary riboflavin supplementations during gravidity and lactation on riboflavin concentrations in blood, liver, and total body of their offspring. Therefore, two experiments with a total of 154 female rats were conducted. In the first experiment the animals received a semisynthetic diet (basal riboflavin concentration of 0.9 mg/kg diet) with various riboflavin supplementations during lactation (0, 2, 4, 6, 8, 10, 12, 40, 400, 4000 mg riboflavin/kg diet). In the second experiment, during gravidity, the rats were fed supplements of 1 or 20 mg riboflavin/kg diet. After parturition each group was divided into three subgroups that received 1, 5 or 20 mg riboflavin/kg with their feed during the following lactation. Both investigations continued until the 14th day of the lactation period just before the pups would start to eat the diets. The total body weights of the offspring in the first experiment only showed an effect of the riboflavin supplementation during lactation in the riboflavin‐deficient group (supplementation of 0 mg/kg diet). Regarding the second experiment, the total body and liver weights of the offspring on the 14th day of lactation were not significantly influenced by the various maternal riboflavin supplements during gravidity and lactation. The data of the first experiment clearly show that there exists a slight dose‐response relationship between the maternal dietary riboflavin supplementation during lactation and the riboflavin concentration in the blood and total body of the offspring. However, a riboflavin supplementation over 8 mg/kg diet led to a saturation of the riboflavin concentration in the body. Also, a dietary supplementation above 2 mg riboflavin/kg diet had no influence on the liver riboflavin concentration. The second investigation showed that the riboflavin concentration in all samples was influenced predominantly by the maternal riboflavin supply during lactation. The riboflavin supply during gravidity had no or only a very slight effect on the riboflavin concentrations in blood, liver, and total body of the offspring. In conclusion, these results indicate the necessity of a sufficient maternal dietary riboflavin supply (8–9 mg/kg diet) during lactation in regard to the health of their offspring and that a high riboflavin supply during gravidity cannot compensate for a deficient supply during lactation.
No evidence for active peptide transport in forestomach epithelia of sheep
Authors: Martens H. , Kudritzki J. , Wolf K. , Schweigel M.
Published: March 2003

The transport of peptides was studied with isolated preparations of rumen and omasum tissue of sheep by using the conventional Ussing‐chamber method and isolated ruminal cells (REC). Mucosal addition of glycyl‐L‐glutamine, captopril (angiotensin converting enzyme inhibitor) or cefadroxil (β‐lactam antibiotic) did not change the short‐circuit current (Isc), or tissue conductance (Gt). The intracellular pH, pHi, in isolated REC was not influenced by the addition of peptides to the buffer solution. These findings do not support the assumption of proton‐coupled or electrogenic peptide transport. The determination of unidirectional flux rates of the peptide D‐phenylalanyl‐L‐alanine (2,3‐3H) showed that the flux rate in the serosal‐mucosal direction, Jsm, was greater than Jms, leading to a small net secretion of peptide. Transport was not significantly inhibited by the serosal addition of ouabain. Enhancing the paracelluIar permeability by an increase of osmotic pressure in the mucosal solution (FREYER and MARTENS, Proc. Soc. Nutr. Physiol. 8, 80, 1999) caused an increase of Gt and significantly higher transport rates of peptide. The flux rates of peptides (in the nanomolar range) may therefore represent passive and possibly paracellular diffusion and are not of nutritional importance.
The effect of crude fibre on apparent digestibility and digestible energy content of extruded dog foods
Authors: Castrillo C. , Vicente F. , Guada J. A.
Published: March 2003

The apparent digestibility of nutrients and energy of 38 commercial dry extruded dog foods was measured using six adult (2 to 3 year‐old) female Beagles. Diets contained [in g/kg dry matter (DM)]: 164–360 crude protein (CP); 79–261 ether extracts (EE); 8–33 crude fibre (CF) and 318–585 nitrogen free extracts (NFE). Apparent energy digestibility ranged from 77.3 to 91.6%, and was closely related to CF content (r=–0.85), yielding the resultant equation: GED (%)=94.00 – 4.04 × CF (% DM). The estimation of digestible energy content of foods from digestibility coefficients predicted from the above equation and gross energy measured or estimated from the Weende fractions, provides a more accurate prediction of experimental values than the Atwater approach followed by the National Research Council and the Association of American Feed Control Officials.
Gustatory responses of pigs to sixty compounds tasting sweet to humans
Authors: NOFRE C. , GLASER D. , TINTI J. ‐M. , WANNER M.
Published: March 2003

The gustatory responses of pigs to 60 compounds perceived as sweet by humans were studied via a semi‐quantitative behavioural method derived from the Richter two‐bottle preference test. Among the 60 compounds tested 35 are effective in pigs, but with an effectiveness much lower in pigs than in humans. Lugduname and carrelame, which are the two most potent sweeteners in humans, are also the most effective compounds in pigs.
Energy and protein metabolism in pregnant sows fed two levels of dietary protein
Authors: Theil P. K. , Jørgensen H. , Jakobsen K.
Published: March 2003

The present study was performed to quantify the energy and nutrient metabolism of pregnant sows fed high (HP) or low (LP) dietary protein [18.3 vs. 13.5% of dry matter (DM)]. A total of nine sows (four on HP and five on LP diet) were subjected to balance and respiration trials four times during their second pregnancy (approximately on days 30, 61, 80 and 104 of gestation). The digestibility of protein (83.0 vs. 79.9) (p < 0.01) and energy (84.9 vs. 83.7%) (p < 0.05) was higher for the HP diet. Daily intake of metabolizable energy (ME) and retained energy (RE) were similar for the two groups, with an average of 28.37 MJ ME and 3.94 MJ RE, respectively. Heat production (HE) measured according to the respiratory quotient (RQ) and carbon–nitrogen (CN) method was similar (464 vs. 454 kJ/kg0.75/day, respectively). Sows fed HP retained more energy in protein (3.33 vs. 2.00 MJ/day) (p < 0.001) and tended to retain less energy in fat (1.59 vs. 2.50 MJ/day) than LP sows. Retained nitrogen (N) (22.3 vs. 13.4 g/day) (p < 0.001) and utilization of N (retained/digested) (45.2 vs. 38.1%) was higher for HP sows compared with LP sows. In late pregnancy, retained N, retained fat, HE and oxidation of carbohydrates increased, while oxidation of fat was reduced to zero. In conclusion, both diets provided adequate N for retention in maternal tissue and conception products. In spite of the lower utilization of N in LP sows, the N excretion was depressed by 5.6 g/day compared with HP sows, because of the lower N intake.
Correlation between the number of adult male Pectinophora gossypiella (Saund.) (Lep., Gelechidae) catches on pheromone traps and the rate of infestation in fruiting bodies of cotton plants by young larvae in three regions of central Greece
Authors: Buchelos C. TH. , Athanassiou C. G. , Papapostolou C. CH. , Georgiou A.
Published: March 2003

In order to evaluate the influence of the number of catches in pheromone‐baited traps on the percentage of larval infestation, six delta traps equipped with sex attractant were placed in each of three regions in Central Greece (Farkadona, Farsala, Almyros) in cotton fields from 20 June until 30 September 1995. The collection of fruiting bodies took place weekly and the counting of adults in the traps was carried out each day. The population fluctuation in all three regions was similar with their peak during the first weeks of August. In Farkadona the infestation level was low (1% at the first sampling of August) with a maximum of 9% in the last sampling of September. In Farsala and Almyros, the infestation level was already high (10% and above) in early August. There was a significant positive linear correlation between the number of moth catches and the infestation percentage from first‐ and second‐stage larvae on the first (R = 0694) and second (R = 0.7399) boll‐feeding generations.
Isolation and characterization of two entomopathogenic nematode strains, Heterorhabditis indica (Nematoda, Rhabditida), from the West Bank, Palestinian Territories
Authors: Iraki N. , Salah N. , Sansour M. A. , Segal D. , Glazer I. , Johnigk S.‐A. , Hussein M. A. , Ehlers R.‐U.
Published: March 2003

Two entomopathogenic nematode strains (Beth 11 and Beth 22) were isolated by trapping with larvae of Galleria mellonella from soil samples taken from the fields near Bethlehem, West Bank. The total length of the nematode dauer juveniles fall within the description for Heterorhabditis indica. Crossbreeding experiments confirmed the designation of the new strains to H. indica. Offspring were recorded when males or females of the Bethlehem strains were cultured together with males or females of the H. indica type strain LN2. No offspring were produced by crosses of the new strains and H. bacteriophora. Sequence analysis of the variable region of the 16S rRNA gene of the symbiotic bacteria Photorhabdus luminescens isolated from the type strain LN2 and other tropical symbionts of H. indica allowed the characterization of a specific group within the species P. luminescens. The symbiotic bacteria isolated from the Bethlehem nematode strains differ in their sequence and thus form a distinct group. The West Bank strains of H. indica are more heat resistant when compared with H. bacteriophora from temperature climatic regions. The LD70 after 26 h exposure to G. mellonella was 25 for Beth 11, 55 for Beth 22 and 160 dauer juveniles for H. bacteriophora. The new isolates seem better adapted for biocontrol of Maladera matrida than the H. bacteriophora strain tested.
Post‐alighting responses of Mexican fruit flies (Dipt., Tephritidae) to different insecticides in paint on attractive spheres
Authors: Prokopy R. J. , Jacome I. , Pinero J. , Guillen L. , Fleischer F. Diaz , Hu X. , Aluja M.
Published: March 2003

Abstract: Two new, comparatively safe insecticides (spinosad and imidacloprid) were compared with dimethoate (each at 1.5% active ingredient) for behavioural and mortality effects on Mexican fruit flies, Anastrepha ludens. Insecticide was mixed with sugar (as a feeding stimulant) and yellow latex paint (as an extending agent) applied to the surface of fruit‐mimicking biodegradable 7 cm spheres made of sugar, flour and glycerin. Flies feeding on spinosad‐treated spheres did not differ from flies feeding on untreated spheres in post‐feeding intra‐tree flight capability, amount of oviposition or mortality. Flies that fed on imidacloprid‐ or dimethoate‐treated spheres for as little as 30 s experienced both high reduction in oviposition and high mortality compared with flies that fed on untreated spheres, and the flies from imidacloprid‐treated spheres also showed a much reduced intra‐tree flight capability. If baited with attractive odour, biodegradable yellow spheres treated with a surface coating of imidacloprid in latex paint and sugar could have potential for suppressing Mexican fruit flies on host trees.
Cartap resistance and synergism in populations of Tuta absoluta (Lep., Gelechiidae)
Authors: Siqueira H. A. A. , Guedes R. N. C. , Picanço M. C.
Published: March 2003

Abstract: Control failures of cartap when used against the tomato leafminer Tuta absoluta (Meyrick) in Brazil and a recent report of cartap resistance in Brazilian populations of this pest species led to the investigation of the possible involvement of detoxification enzymes on this phenomenon using insecticide synergists. The insect populations were collected from seven different sites in the states of Minas Gerais, Rio de Janeiro and São Paulo. These populations were subjected to insecticide‐impregnated filter paper assays. The concentration–mortality assays were carried out for cartap alone and in a mixture (1 cartap : 10 synergist) with the synergists diethyl maleate, piperonyl butoxide and triphenylphosphate which, respectively, inhibit the enzymes glutathion‐S‐transferases, cytochrome P450‐dependent monooxygenases and esterases. Resistance to cartap was observed in all populations when compared with the standard susceptible population, with resistance ratios ranging from 2.3‐ to 21.9‐fold. Piperonyl butoxide was the most efficient synergist with cartap synergism ratios ranging from 1.3‐ to 21.0‐fold and nearly completely suppressing the resistance to cartap in all of the populations studied, suggesting a major involvement of cytochrome P450‐dependent monooxygenases as a cartap resistance mechanism in these populations of T. absoluta. Diethyl maleate and triphenylphosphate also synergized cartap in nearly every population, and they still provided partial suppression of cartap resistance in the leafminer populations studied. Therefore, glutathion‐S‐transferases and esterases seem to play a secondary role in cartap resistance in Brazilian populations of T. absoluta.
An extended laboratory method maximizing plant contact time to study the side‐effects of pesticides on plant‐dwelling predators
Authors: Schaub L. , Garnier G. , Bloesch B.
Published: March 2003

An extended laboratory method was developed to study the side‐effects of pesticides on plant‐dwelling, walking beneficial insects such as anthocorids, coccinellids and chrysopids. By using a glass funnel with a slippery surface, larvae of Anthocoris nemoralis, a natural enemy of pear psylla, stayed mainly on the treated plant surface and access to untreated surfaces was discouraged. The optimal ventilation produced a favourable environment and low mortality in the control. Tests with seven insecticides on the anthocorid larvae produced consistent toxicity results.
Effects of starvation on the search path characteristics of Orius majusculus (Reuter) (Het., Anthocoridae)
Authors: Hénaut Y. , Alauzet C. , Lambin M.
Published: March 2003

Abstract: Orius majusculus (Reuter) is a polyphagous predator bug used to control western flower thrips Frankliniella occidentalis (Pergande). As physiological factors may be highly influential upon the predatory behaviour of Orius spp. we studied the possible impact of starvation on the search path of this bug. Orius majusculus was maintained on a diet of Ephestia kuehniella Zeller (Lep., Pyralidae) eggs in laboratory. Adults were collected immediately after the imaginal moult and were individually placed in Petri dishes with abundant food. Each adult was randomly assigned to one of the following five treatments: immediate observation or starved for 2, 6, 9 or 12 h prior to observation. The observation procedure consisted of placing a single O. majusculus adult at the centre of an empty arena. The displacement of each insect was recorded with a video camera until it had reached the limits of the arena. The recorded paths were digitized and the digitized search path was used to calculate the mean walking speed, the number of stops per second, the duration of stops and the diffusion rate. The results clearly show that, in comparison with unstarved bugs, insects that experienced 6 h of prey deprivation walked more slowly, stopped more frequently and for longer periods, and had a lower rate of diffusion away from the release point. In contrast, all search path variables returned to the levels measured in unstarved bugs in the group that experienced the longest period of starvation (12 h), whereas groups of O. majusculus that had experienced 2 or 9 h of prey deprivation presented intermediate values for all the variables tested. Starvation produced evident changes in the search path characteristics that we assume to be related to physiological states of hunger and energy availability. These behavioural changes related to physiological state could have consequences for the use of this pirate bug in biological control.
Influence of the proportion of (−) α‐pinene in pheromone bait on Ips typographus (Col., Scolytidae) catch in pheromone trap barriers and in single traps
Authors: Jakuš R. , Blaženec M.
Published: March 2003

Abstract:  Further possibilities of increasing catch efficiency of Ips typographus L. in pheromone trap barriers with two different levels of release of (4S)‐cis‐verbenol (cV) and in single traps were tested. Pheromone mixtures containing cV, 2‐methyl‐3‐buten‐2‐ol (MB) and 0, 1, 10, 35, 60 and 90% (−) α‐pinene were prepared. Basically, MB was successively replaced by (−) α‐pinene in the mixtures. Tests were performed on the edge of a spruce forest when outbreaks of I. typographus occurred. The substitution of MB with (−) α‐pinene had different effects in different types of pheromone trap barriers and in single traps. It is not possible to increase the attractiveness of the bait having a higher percentage of cV by supplementing a certain percentage of MB with (−) α‐pinene. The catch of I. typographus decreased with an increase in the percentage of (−) α‐pinene in the bait. It is possible to increase the attractiveness of the bait having a lower percentage of cV by supplementing certain percentages of MB with (−) α‐pinene. A slight synergistic effect of (−) α‐pinene with MB/cV mixture is visible in this type of bait. In the case of single traps, supplementing MB with (−) α‐pinene possibly causes a slight synergistic effect. An increase in the percentage of (−) α‐pinene increases the percentage of males in the catch.
Institut National de la Recherche Agronomique, Unité de recherches intégrées en grandes cultures, Le Rheu cedex, France
Authors: Gac M. L. , Montfort F. , Cavelier N. , Hourmant P.
Published: March 2003

Tapesia yallundae and Tapesia acuformis are the causal agents of eyespot, the major foot disease of cereals. Many authors have suggested that the two species differ in epidemiological behaviour, based on the later appearance of lesions with T. acuformis than with T. yallundae. However, the reasons for this difference in natural conditions are unclear in the absence of a method to distinguish the two species in the plant before the symptoms appear. Methods of detection [visual assessment, enzyme‐linked immunosorbent assay, polymerase chain reaction (PCR) test] and characterization (isolation on artificial medium, PCR test) were used to investigate the behaviour of Tapesia spp. in the field under various epidemiological conditions. The PCR test was used to determine infection dates and to identify the species involved early, in order to demonstrate that infection occurred at the same time for T. yallundae and T. acuformis. Symptoms of T. acuformis infection occurred later because the pathogen developed more slowly in the tissues. A triticonazole seed treatment was used to evaluate the effectiveness of the PCR test for estimating fungicidal effects. This molecular tool for determining the period of activity of the chemical and changes in the proportions of the two species of Tapesia involved in the disease was demonstrated to be accurate. The PCR test either had advantages over or was complementary to the other methods tested.
Species‐specific PCR Assays for the Fungal Pathogens Fusarium moniliforme and Fusarium subglutinans and their Application to Diagnose Maize Ear Rot Disease
Authors: Möller E. M. , Chełkowski J. , Geiger H. H.
Published: March 2003

Fusarium moniliforme Sheldon (syn. F. verticillioides (Sacc.) Nirenberg) and F. subglutinans (Wollenweber & Reinking) Nelson Toussoun & Marasas comb. nov., two anamorphs of the so‐called‘Gibberella fujikuroi species complex', are important maize pathogens. Together with F. proliferatum, F. culmorum, and F. graminearum (teleomorph: Gibberella zeae) they are involved in the stalk rot and ear rot disease of maize. All species produce secondary metabolites (mycotoxins) which are a potential health hazard for humans and animals that consume maize and maize products frequently. In this study the development of polymerase chain reaction (PCR) assays for an easy and sensitive identification of G. fujikuroi anamorphs in maize kernels are described. The primer pairs are based on sequences of randomly amplified polymorphic DNA (RAPD) fragments and are specific for F. moniliforme and F. subglutinans respectively. The PCR assays are independent of the high phenotypic variability of traits which may complicate classification by morphological characters. They detect approximately 100 to 200 fungal genomes in the presence of an excess of maize DNA. For the analysis of infected maize kernels a rapid and easy DNA extraction was used which does not introduce inhibitory substances into the PCR. Hence the assays enable an early identification and detection of the two pathogens in host tissue by plant breeders and plant health inspection services. The assays were successfully applied to identify field isolates from Poland and to detect the pathogens in maize ears of various hybrids in Germany.
Water Stress and Verticillium Wilt Severity on Eggplant (Solanummelongena L.)
Authors: Bletsos F. A. , Thanassoulopoulos C. C. , Roupakias D. G.
Published: March 2003

Verticillium wilt is one of the most destructive diseases of eggplant (Solanum melongena L.). Some researchers have reported that wilt was encouraged by sufficient soil humidity, while others stated that it was encouraged by drought. This study investigated the water stress effect on the severity of Verticillium wilt on eggplant, as it is reflected on yield, agronomic traits and fruit quality. Thus, eggplant seedlings cv. ‘Tsakoniki’ were transplanted in three rows, each with 20 plants, during the summer of 1995 and 1996 in a plastic greenhouse, at the Agricultural Research Center of Macedonia and Thrace. Ten of the plants in each row were inoculated with the fungus Verticillium dahliae, while the other 10 were used as controls. Rows were irrigated every 2, 4 or 6 days. Soil humidity was calculated before every irrigation in each row. The disease severity was estimated by the disease index (DI) as the combination product of leaf symptom index (LSI) and vascular discoloration index (VDI). In addition, the plant height, early and total commercial yields, fruit numbers of early and total commercial yields, plant weight, the above‐ground plant weight, root weight, pH, total soluble solids and fruit brilliance plus colour intensity were measured. The effect of Verticillium wilt on plants irrigated every 2, 4 or 6 days was estimated by the correlation coefficient (r) between LSI and DI and the aforementioned characteristics. Verticillium wilt had a significant but negative effect on all of the measured or calculated characteristics. This effect, however, was independent of the irrigation applied. On average, the early commercial yield was reduced by 40.8% and the final commercial yield by 39.4%. The only quality characteristic that was affected significantly by irrigation was the fruit brilliance and colour intensity (r =−0.640 to − 0.727, P ≤ 0.01). Finally, the irrigation frequency (every 2, 4 or 6 days) had a significant but negative effect on all of the characteristics measured on the control plants. The only exception was fruit quality. In conclusion, the combined effect of irrigation and Verticillium wilt infection significantly reduced the early and total production of eggplant and spoiled the fruit quality.
Identification of Indian Landraces of Opium Poppy Papaver somniferum Resistant to Damping‐off and Downy Mildew Fungal Diseases
Authors: Bajpai S. , Gupta M. M. , Kumar S.
Published: March 2003

A set of 32 landraces (traditional local cultivars) of poppy Papaver somniferum originating in the Indian states of Rajasthan, Madhya Pradesh, Uttar Pradesh and Tamilnadu, and four Indian commercial varieties were screened over four cropping seasons for their reaction to downy mildew disease caused by Peronospora arborescens and damping‐off disease caused by Pythium dissotocum under both field and artificial inoculation conditions. The landrace 1018 was found to be resistant to damping‐off disease and the landraces 1014 and N3 were resistant to downy mildew disease. A yield trial conducted over two seasons showed that the damping‐off disease‐resistant landrace 1018 was superior to all the commercial varieties in seed, morphine and/or codeine yield. The experiments provided further evidence that there is considerable genetic variability between the landraces.
Identity and Pathogenicity of Fungi Associated with Root and Crown Rot of Soft Red Winter Wheat Grown on the Upper Coastal Plain Land Resource Area of Mississippi
Authors: Gonzalez M. S. , Trevathan L. E.
Published: March 2003

Seedling stand, disease severity and fungal incidence were determined from untreated ‘Wakefield’ soft red winter wheat planted on a Leeper silty clay loam in field tests conducted at the Mississippi Agricultural and Forestry Experiment Station, Plant Science Research Center, Mississippi State University, Starkville, Mississippi during the 1996–97 and 1997–98 growing seasons. Seedling stand was reduced by 40% each year in plots established with untreated seed.Cochliobolus sativuswas the most frequently isolated fungus.Fusarium acuminatum,Fusarium equisetiandFusarium solaniwere the most prevalentFusariumspp. Seven otherFusariumspp. and 23 species of other fungal genera were isolated. Pathogenicity tests with three isolates each ofC. sativus,Cochliobolus spicifer,F. acuminatum,F. solani,F. equiseti,Fusarium compactum,Embellisia chlamydosporaandMicrodochium bolleyiwere performed in test tube culture and two isolates each ofC. sativus,C. spicifer,F. acuminatum,E. chlamydosporaandM. bolleyiunder greenhouse conditions. In test tubes and in the greenhouse, seedlings infected with isolates ofC. sativusdeveloped seedling blight, discoloration and necrosis, primarily in seminal roots and crowns. In the greenhouse,C. sativusinduced lesions on the lower leaf sheath and reduced seedling height, seedling emergence, dry and fresh weight of roots and shoots. Isolates ofF. acuminatum,F. solani,F. equiseti,F. compactum,E. chlamydosporaandM. bolleyiinduced slight to moderate orange to light‐brown discoloration of crown and seminal roots in test tubes.Cochliobolus spiciferisolates had the most pre‐emergence activity, inducing black root discoloration and root pruning of wheat seedlings and reducing seedling emergence, root fresh weight and shoot dry weight. In the greenhouse,F. acuminatumreduced seedling height, seedling emergence and root and shoot dry weights.Microdochium bolleyiandE. chlamydosporareduced fresh and dry weight of roots, plant emergence and shoot dry weight.Fusarium acuminatumandC. spiciferreduced the growth rate of wheat seedlings. All fungi evaluated showed increased disease severity compared to the untreated control. The high frequency of isolation ofC. sativusfrom crown and root tissues can be partially explained by the dry, warm conditions during the early stages of wheat seedling development in the Upper Coastal Plain Land Resource Area of Mississippi.