Rootstock Effects on Pistachio Trees Grown in Verticillium dahliae-Infested Soil

ABSTRACT In a field trial in soil infested with Verticillium dahliae, we compared the yield, growth, incidence of symptoms of Verticillium wilt, and mortality of two interspecific hybrid pistachio tree rootstocks (UCBI and PGII) with the standard rootstocks: the V. dahliae-resistant and susceptible Pistacia integerrima and P. atlantica, respectively. After 10 years, the trees were destructively sampled for V. dahliae in the xylem at the graft union. The results indicate that trees on the (P. atlantica 'KAC' x P. integerrima) hybrid UCBI rootstock grew and yielded as well as those on P. integerrima. Trees on the hybrid PGII yielded the least. Analysis of variance and log-linear models indicate that in soil infested with V. dahliae, three associations significantly affect pistachio nut yield. Rootstock affects scion vigor and extent of infection. Third, the extent of infection and scion vigor are inversely associated. Although trees on the P. integerrima rootstock had the highest ratings in a visual assessment of vigor, 65% were infected with V. dahliae in the trunk in the graft region compared with 73% in P. atlantica and 25% in UCBI. Thus, P. integerrima and UCBI have at least one different mechanism for resistance to V. dahliae.     

Comparison of in vitro and in vivo fertilizing potential of buffalo bull semen frozen in egg yolk‐, soya bean lecithin‐ and liposome‐based extenders

The objective of this study was to compare different extenders for post‐thaw in vitro sperm function and in vivo fertility of buffalo semen. Accordingly, sperm of 30 ejaculates extended in egg yolk (TRIS with 20% egg yolk; EY), two soya lecithin‐based (SL‐1; AndroMed^® and SL‐2; Bioxcell^®) and a liposome‐based extender (LS; OptiXcell^®) were tested. The post‐thaw semen was evaluated for computer‐assisted sperm analysis (CASA), sperm viability, membrane and acrosome integrity, DNA integrity and acrosome reaction and first service pregnancy rate (FSPR) in a fixed‐time artificial insemination programme. Total motility and VCL were the only CASA‐based parameters that exhibited significantly higher (p < .05) percentage in LS among these extenders. Post‐thaw percentage of acrosome integrity (55.9 ± 1.4, 58.1 ± 2.0, 55.8 ± 2.0, 56.6 ± 2.3) and DNA integrity (68.8 ± 2.0, 69.2 ± 2.3, 71.3 ± 2.1, 69.1 ± 2.1) did not differ (p > .05) in EY, SL‐1, SL‐2 and LS extender, respectively. However, a variable response in terms of efficacy of different extenders for sperm viability and plasma membrane integrity was observed. Assessment of inducibility of acrosome reaction showed significant differences between extenders (51.9 ± 2.1, 44.3 ± 2.4, 46.1 ± 2.3 and 58.1 ± 3.1%, respectively, for EY, SL‐1, SL‐2 and LS). Furthermore, field trials revealed significantly higher (p < .05) FSPR of LS‐extended semen as compared to that for EY, SL‐1 and SL‐2 extender (46.3%, 41.2%, 31.2% and 29.7%, respectively). It is concluded that the liposome‐based extender is more effective than egg yolk‐ and soya lecithin‐based extenders and may be used for cryopreservation of buffalo semen in the future.     

Exploration for anti-insect properties of lectin from seeds of soybean (Glycine max) usingBactrocera cucurbitae as a model

Lectin fromGlycine max L. was extracted and purified by affinity chromatography using asialofetuin-linked porous amino-activated silica beads. The concentration-dependent effect of lectin was studied on freshly laid eggs (0–8 h old) of the melon flyBactrocera cucurbitae (Coquillett); lectin failed to influence egg hatching. However, treating second instar larvae (64–72 h old) with increasing concentrations of lectin significantly reduced the development period, number of pupae and number of emergingB. cucurbitae, and was negatively correlated with the increase in the lectin concentration. The LC₅₀ value, 54μg ml⁻¹, was calculated on the basis of adult emergence. Treatment of the larvae (64–72 h old) with the LC₅₀ concentration resulted in a decrease in pupal weight. The activity of three hydrolase enzymes (esterases, acid and alkaline phosphatases), one oxidoreductase (catalase) and one group transfer enzyme (glutathione S-transferase) was assayed in second instar larvae at the LC₅₀ concentration of lectin after exposure for 24, 48 and 72 h. The activity of esterases increased significantly (P<0.01) at the three exposure intervals, whereas the activities of the three other hydrolyses and the transferases were significantly suppressed (P<0.01). http://www.phytoparasitica.org posting Sept. 13, 2006.     

Pharmacokinetics, urinary excretion and dosage regimen of diminazene in crossbred calves

The pharmacokinetics, urinary excretion and dosage regimen of diminazene were investigated in crossbred male calves following a single intramuscular dose (3.5 mg x kg-1). Following intramuscular administration, the pharmacokinetics of diminazene was described with a one-compartment open model. The absorption rate constant and absorption half-life were 9.86 +/- 3.06 h-1 and 0.121 +/- 0.40 h, respectively. The value of elimination half-life was 107.5 +/- 8.50 h. The apparent volume of distribution was 0.74 +/- 0.07 L x kg-1. Systemic availability following intramuscular administration was 91.7%. Approximately 65% of the administered dose of diminazene was eliminated in the urine within 24 h of its intramuscular administration. Diminazene was bound to plasma proteins to the extent of approximately 32%. The satisfactory intramuscular dosage regimen of diminazene for calves would be 2.24 mg x kg-1 followed by 1.5 mg x kg-1 at 7 days.     

Estimation of nitrogen and sulfur mineralization in soils amended with crop residues contributing to nitrogen and sulfur nutrition of crops in the North Central U.S

Predicting nitrogen (N) and sulfur (S) mineralization of crop residues from the preceding crop might be a useful tool for forecasting soil N and S availability. Two soils from eastern North Dakota and three crop residues – corn, spring wheat, and soybean were used in an 8-week incubation study to estimate N and S mineralization from crop residues. The cumulative N and S mineralized were fit to a first-order kinetic model. Cumulative N mineralized ranged between 0.34 and 2.15 mg kg^?1 and 0.45 to 3.41 mg kg^?1 for the Glyndon and Fargo soils, respectively. Un-amended soils showed higher N mineralization than residue treated soils. For S, the highest mineralization occurred in un-amended Glyndon soil and in spring wheat-amended Fargo soil. This study indicates that crop residue additions can have a negative impact on plant available nutrients due to immobilization of N and S during the time when crops need the nutrients most.     

A comparative study of monoterpenoids and phenylpropanoids from essential oils against stored grain insects: acute toxins or feeding deterrents

The relationship between the acute toxicity and feeding deterrent activity of ten compounds occurring commonly in essential oils was explored in order to determine whether they are acute toxins or antifeedants against stored-grain pests. Simultaneously, the objective was also to demonstrate the comparative efficacy against three post-harvest stored-grain pests. Thymol, carvacrol, eugenol and trans-anethole were specifically toxic, and linalool was a generalist feeding deterrent against all three species studied. Thymol was most toxic to Tribolium castaneum and Rhyzopertha dominica compared to carvacrol and eugenol but was least toxic to Sitophilus oryzae. Similarly, linalool deterred feeding of S. oryzae (FI₅₀ = 0.025 mg/g of the wafer diet), T. castaneum (FI₅₀ = 0.207 mg/g of the wafer diet) and R. dominica (FI₅₀ = 0.482 mg/g of the wafer diet) at different concentrations; R. dominica beetles required about 20 times the concentration to deter feeding compared to S. oryzae and more than twice compared to T. castaneum. Comparison of toxicity and deterrent activity with respective artificial blends as binary mixtures revealed that synergism was not a generalized phenomenon, and the variations were both species as well as blend specific. Individual compound efficacy correlations were not ascertained, which suggests that artificial blends could be prepared to obtain potential mixtures for substantial control of stored-grain insect pests. The present study also implies that the compounds are mostly acute toxins, and whatever inhibition in feeding was obtained could be due to physiological toxicity rather than any interaction with gustatory receptors.     

Induced defense dynamics in plant parts is requisite for resistance to <Emphasis Type="Italic">Helicoverpa armigera</Emphasis> (Hubner) infestation in chickpea

Helicoverpa armigera is the most serious insect pest in chickpea that causes significant yield losses due to its feeding on vegetative (leaves) and reproductive (developing pods and seeds) parts of plants. The present aim of study was to explore response dynamics of induced defence mechanism in leaves, podwall and seeds of ten chickpea genotypes (ICC 506, ICCV 10, ICC 10393, 5283, RSG 963, GL 25016, GL 26054, ICCL 86111, ICC 3137, L 550) after insect infestation. Two chickpea genotypes namely ICC 3137 and L 550 were found to be highly susceptible to Helicoverpa armigera infestation due to higher leaf and pod damage in them as compared to rest of eight genotypes which are found to be considerably resistant due to lower damage. Insect infestation induced decreased activities of defensive enzymes such as peroxidase (POD), catalase (CAT), glutatione reductase (GR) and polyphenol oxidase (PPO), decreased free radical scavenging activities in terms of 2,2-diphenyl-1-picryl hydrazyl (DPPH), decreased contents of signaling molecules such as nitric oxide ((NO), hydrogen peroxide (H₂O₂), reduced content of insect feeding behaviour regulating molecules such as total phenols, trypsin inhibitor and accumulation of membrane damage marker such as malondialdehyde (MDA) in leaves of ICC 3137 and L 550; decreased POD activity, nitric oxide content and H₂O₂ in podwall of L550; decreased SOD, GR, nitric oxide content and H₂O₂ in seeds of L550 resulted in aggravation of infestation induced oxidative stress and makes these genotypes more vulnerable to insect damage. The resistance of rest eight chickpea genotypes to insect infestation was due to the integrative effect of up regulated defensive components in leaves, podwall and seeds such as enhanced activities of CAT, POD, GR, PPO and PAL along with accumulation of H₂O₂` and total phenols in leaves, increased SOD, POD, GR and PPO activities along with increased contents of trypsin inhibitor and total phenols in podwall; increased SOD, GR, PPO activities and accumulated total phenols in seeds of resistant chickpea genotypes might be responsible for causing significant shift in oxidative status of these genotypes due to scavenging of free radicals, maintenance of membrane integrity and deterrent to insect feeding. Induced glycine betaine after herbivory was found to be positively correlated with superoxide dismutase and trypsin inhibitors. H₂O₂ content was positively correlated with trypsin inhibitor, DPPH, ferric reducing antioxidant power (FRAP) and total phenols in leaves and with FRAP, DPPH and total phenols in pod wall indicating that H₂O₂ might be stimulating the cascade that will be helping to scavenge free radical species and correlation with phenols and trypsin inhibitor indicated that it act as toxicant to insect feeding.     

Transfer of leaf rust and stripe rust resistance from <Emphasis Type="Italic">Aegilops umbellulata</Emphasis> Zhuk. to bread wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

Aegilops umbellulata acc. 3732, an excellent source of resistance to major wheat diseases, was used for transferring leaf rust and stripe rust resistance to cultivated wheat. An amphiploid between Ae. umbellulata acc. 3732 and Triticum durum cv. WH890 was crossed with cv. Chinese Spring Ph ^I to induce homoeologous pairing between Ae. umbellulata and wheat chromosomes. The F₁ was crossed to the susceptible Triticum aestivum cv. ‘WL711’ and leaf rust and stripe rust resistant plants were selected among the backcross progenies. Homozygous lines were selected and screened against six Puccinia triticina and four Puccinia striiformis f. sp. tritici pathotypes at the seedling stage and a mixture of prevalent pathotypes of both rust pathogens at the adult plant stage. Genomic in situ hybridization in some of the selected introgression lines detected two lines with complete Ae. umbellulata chromosomes. Depending on the rust reactions and allelism tests, the introgression lines could be classified into two groups, comprising of lines with seedling leaf rust resistance gene Lr9 and with new seedling leaf rust and stripe rust resistance genes. Inheritance studies detected an additional adult plant leaf rust resistance gene in one of the introgression lines. A minimum of three putatively new genes—two for leaf rust resistance (LrU1 and LrU2) and one for stripe rust resistance (YrU1) have been introgressed into wheat from Ae. umbellulata. Two lines with no apparent linkage drag have been identified. These lines could serve as sources of resistance to leaf rust and stripe rust in breeding programs.     

Screening of water-efficient rice genotypes for dry direct seeding in South Asia

Rice genotypes having high crop water productivity in dry direct-seeded rice (DDSR) need to be assessed while promoting labor- and water-saving technology. The objective of this study was to evaluate the ability of several selection indices to identify genotypes with high crop water productivity in DDSR. A set of 16 genotypes [13 recombinant inbred lines (RILs) and three genotypes as check for control] were evaluated under DDSR for two consecutive years (2013 and 2014) using two irrigation regimes [-10 kPa (non-stress) and -20 kPa (stress)]. Grain yield varied from 5.3 to 8.4 t ha^-1 and 5.9 to 8.7 t ha^-1 for irrigation regimes of -20 and -10 kPa, respectively. Yield reductions caused by water stress ranged from 2.9 to 25.1%; being lowest in RIL1649 and highest in hybrid SVH-127. The genotypes with high stress-tolerance index (STI), mean productivity (MP), geometric mean productivity (GMP) and harmonic mean productivity (HAR) were identified as the most productive genotypes for high crop water productivity in DDSR. The results implied that selection based on stress tolerance indices likes STI, MP, GMP and HAR was useful in identifying genotypes with high crop water productivity under DDSR and RIL 1649 and SVH-127 were identified as superior genotypes in this regard.     

Eucalyptus essential oil as a natural pesticide

Eucalyptus (family Myrtaceae), an Australian native, represented by around 700 species is a genus of tall, evergreen and magnificent trees cultivated world over for its oil, gum, pulp, timber, medicine and aesthetic value. Among the various wood and non-wood products, essential oil found in its foliage is the most important one and finds extensive use in food, perfumery and pharmaceutical industry. In addition, the oil possesses a wide spectrum of biological activity including anti-microbial, fungicidal, insecticidal/insect repellent, herbicidal, acaricidal and nematicidal. The present paper discusses this environmentally benign pest control using eucalyptus oils against bacteria, fungi, insects, nematodes, weeds and mites. The use of eucalyptus oil as a natural pesticide is of immense significance in view of the environmental and toxicological implications of the indiscriminate use of synthetic pesticides and overcoming/reducing the problem of increasing pest resistance.