Molecular diversity of Egyptian cotton (<Emphasis Type="Italic">Gossypium barbadense</Emphasis> L.) and its relation to varietal development

Twenty-eight Egyptian cotton (Gossypium barbadense L.) genotypes (varieties and hybrids) were used for analysis of genetic diversity using DNA based markers (ISSR, SSR, and EST) and to study varietal development of cotton. The ISSR markers gave the highest percentage of polymorphic bands as well as polymorphic information content compared with the other molecular markers (i.e. EST and SSR markers). Using clustering analysis, no general clustering according to the pedigree history of the genotypes was observed. Using principal coordinate analysis (PCOORDA), cotton genotypes were separated by the first three principal coordinates (PC1, PC2, and PC3) accounting for 11.5, 8.6, and 7.2% of the total genetic variance, respectively. The cotton genotypes were distributed into three parts based on the first PC, each part containing a group of varieties having a common ancestor. ‘Giza 12’ variety was the common ancestor for the varieties included in the first part and ‘Ashmouni’ variety was the common ancestor for the varieties included in the second part, while both ‘Sakha 3’ and ‘Sakha 4’ varieties were common ancestors for the varieties included in the third part. The results of the PCOORDA also showed better resolution of the genetic diversity than cluster analysis especially in the illustration of the varietal development of cotton. That means that principal coordinate analysis can be strongly used either alone or in combination with cluster analysis to discuss both genetic diversity and varietal development in the cotton genotypes.     

Effects of warming, wetting and nitrogen addition on substrate-induced respiration and temperature sensitivity of heterotrophic respiration in a temperate forest soil

Soil heterotrophic respiration and its temperature sensitivity are affected by various climatic and environmental factors.However,little is known about the combined effects of concurrent climatic and environmental changes,such as climatic warming,changing precipitation regimes,and increasing nitrogen(N)deposition.Therefore,in this study,we investigated the individual and combined effects of warming,wetting,and N addition on soil heterotrophic respiration and temperature sensitivity.We incubated soils collected from a temperate forest in South Korea for 60 d at two temperature levels(15 and 20℃,representing the annual mean temperature of the study site and 5℃warming,respectively),three moisture levels(10%,28%,and 50%water-filled pore space(WFPS),representing dry,moist,and wet conditions,respectively),and two N levels(without N and with N addition equivalent to 50 kg N ha^-1year^-1).On day 30,soils were distributed across five different temperatures(10,15,20,25,and 30℃)for 24 h to determine short-term changes in temperature sensitivity(Q₁₀,change in respiration with 10℃increase in temperature)of soil heterotrophic respiration.After completing the incubation on day 60,we measured substrate-induced respiration(SIR)by adding six labile substrates to the three types of treatments.Wetting treatment(increase from 28%to 50%WFPS)reduced SIR by 40.8%(3.77 to 2.23μg CO₂-C g^-1h^-1),but warming(increase from 15 to 20℃)and N addition increased SIR by 47.7%(3.77 to 5.57μg CO₂-C g^-1h^-1)and 42.0%(3.77 to 5.35μg CO₂-C g^-1h^-1),respectively.A combination of any two treatments did not affect SIR,but the combination of three treatments reduced SIR by 42.4%(3.70 to 2.20μg CO₂-C g^-1h^-1).Wetting treatment increased Q₁₀by 25.0%(2.4 to 3.0).However,warming and N addition reduced Q₁₀by 37.5%(2.4 to 1.5)and 16.7%(2.4 to 2.0),respectively.Warming coupled with wetting did not significantly change Q₁₀,while warming coupled with N addition reduced Q₁₀by 33.3%(2.4 to 1.6).The combination of three treatments increased Q₁₀by 12.5%(2.4 to 2.7).Our results demonstrated that among the three factors,soil moisture is the most important one controlling SIR and Q₁₀.The results suggest that the effect of warming on SIR and Q₁₀can be modified significantly by rainfall variability and elevated N availability.Therefore,this study emphasizes that concurrent climatic and environmental changes,such as increasing rainfall variability and N deposition,should be considered when predicting changes induced by warming in soil respiration and its temperature sensitivity.     

Flower yield performance and stability of various Rosa damascena Mill. landraces under different ecological conditions

The flower yield stability of Damask rose as an important medicinal and aromatic plant at different environments has not been well documented. In order to evaluate flower yield and stability, 35 landraces of Damask rose were studied at 8 locations in Iran during 2007–2008. Analysis of variance revealed significant differences (p ≤ 0.01) among landraces (G), environments (E), locations (L) and for landrace × environment (GE) and landrace × location (GL) interactions. Both GE and GL interactions were mainly crossover, a large portion of which was accounted for by non-linear (unpredictable) component. The landraces of IS9, YZ2, WA1, IS7 and IS1 with 3120.63, 2941.63, 2894.62, 2769.15 and 2716.92 kg/ha respectively produced the highest flower yield among studied landraces. Kerman with average flower yield of 3635.46 kg/ha produced the highest yield among studied locations. According to the results, most of landraces that originated from temperate, warm temperate and arid regions produced higher flower yield than those from cool, cool temperate, semi-arid and humid regions. The landraces of YZ2, IS5, IS8, IS4, KZ1, AR1_, IS3 and BA1 were stable and YZ2, IS5, IS8, IS4, KZ1, AR1 IS6, IS3, BA1, IS10 and YZ1 were adaptable landraces for flower yield according to Eberhart and Russell (1966) model. The presence of some high flower yield and stable landraces such as YZ2 and IS5 suggests that a genotype can demonstrate high flower yield and stability for yield simultaneously. Thus, simultaneous selection for flower yield and stability using nonparametric methods could be possible. In addition, taking into consideration flower yield and stability potential, the landraces of YZ2, IS5, IS8, IS4 and KZ1 as general stable, adaptable, and high flower yield are recommended. Furthermore, the landraces of IS9 and WA1 as high flower yield and specific adaptable landraces can be recommended for temperate and arid areas and the landraces of IS7 and IS1 for semitemperate and cool areas.     

Fish meal replacement with rice protein concentrate in a practical diet for the Pacific white shrimp, Litopenaeus vannamei Boone, 1931

Replacement of fish meal (FM) with rice protein concentrate (RPC) as a practical diet for the Pacific white shrimp, Litopenaeus vannamei, was evaluated. Five isonitrogenous (36.6% protein) diets, formulated by replacing 0, 25, 50, 75, and 100% of FM by RPC, were fed to shrimp (initial weight of 6.99 ± 0.08 g) five times daily to satiation for 60 days. Relatively high final weight (FW 17.64–18.25 g) and weight gain (WG 10.81–11.39 g) were obtained in treatments up to 50% of the plant protein inclusion. Above this inclusion level, FW (14.93–14.35 g) and WG (7.68–7.23 g) were reduced. Survival was high (≥95%) and similar for all diets. There were no significant differences (P > 0.05) in tail-muscle composition (moisture, protein, lipid, and ash) among different dietary treatments. Dispensable and indispensable amino acids of the tail muscle of shrimp fed with 25, 50, and 75% RPC were significantly higher than the FM (0%) and 100% RPC diets. A decreasing trend in apparent digestibility coefficient (excluding dry matter) for crude protein (90.52–52.41), ether extract (94.11–80.03), organic matter (87.25–50.16), and gross energy (89.41–55.24) was observed at higher RPC inclusion rates. The results suggest that RPC meal can be a potential candidate for FM replacement up to 50% of the protein in shrimp diets.     

Effects of inoculation with stress-adapted arbuscular mycorrhizal fungus Glomus deserticola on growth of Solanum melogena L. and Sorghum sudanese Staph. seedlings under salinity and heavy metal stress conditions

The beneficial effects of a Glomus deserticola strain isolated from the rhizosphere of grasses (belonging to Poaceae family) growing along the industrial waste from a distillery were investigated under stress conditions. The study was conducted to assess the efficacy of the arbuscular mycorrhizal (AM) fungal ecotype in salinity and heavy metal (HM) tolerance of eggplant (Solanum melongena L.) in soils amended with various stress levels of NaCl, zinc and cadmium. Mycorrhizal (M) seedlings produced a significantly (p < 0.05) greater growth response and were more tolerant to salt and HM stresses than nonmycorrhizal (NM) seedlings in all treatments. The HM contents in the plant tissues were significantly higher in M than NM eggplants. Furthermore, when the efficacy was compared with other AM isolates in HM-polluted soils with Sudan grass (Sorghum sudanese Staph.) as a test plant, the AM ecotype responded best to these soils, as evident from the significantly greater growth response and its aggressiveness in colonizing roots in all soil types tested. These results suggest that this G. deserticola ecotype can be used as an effective tool to alleviate the adverse effects of excessive salinity and HM toxicity on plant growth. Finally, the isolate may have potential in the bioremediation of polluted soils.     

Actions of quinolizidine alkaloids on Periplaneta americana nicotinic acetylcholine receptors

BACKGROUND: Botanical insecticides do not play a major role as crop protectants, but they are beneficial in some applications. The authors investigated the actions of naturally occurring alkaloids on insect nicotinic acetylcholine (ACh) receptors (nAChRs) by evaluating their abilities to inhibit specific binding of [³H]imidacloprid (IMI) to nerve‐cord membranes from Periplaneta americana L. Two alkaloids were also tested for their actions on nAChRs expressed by cockroach neurons using patch‐clamp electrophysiology. RESULTS: Four natural quinolizidine alkaloids (matrine, sophocarpine, cytisine and aloperine) exhibited more than 50% inhibition of [³H]IMI binding at 10 µM , although other compounds were found to have no or low inhibitory activity. The rank order of potency based on concentration–inhibition curves was cytisine > sophocarpine ≥ aloperine ≥ matrine. Patch‐clamp analysis indicated that sophocarpine and aloperine were not agonists of nAChRs expressed in P. americana neurons, yet, at 10 µM , aloperine, but not sophocarpine, suppressed ACh‐induced inward currents significantly. CONCLUSION: Three of the four natural alkaloids tested possess structural moieties that are necessary for interaction with P. americana nAChRs. Aloperine, which possesses a unique structure and showed a distinctive dose–response curve, was found to act as an antagonist. Appropriate modifications of these alkaloids might result in novel insecticidal nAChR ligands. Copyright © 2008 Society of Chemical Industry     

Soil C and N dynamics and maize (Zea may L.) yield as affected by cropping systems and residue management in North-western Pakistan

This paper presents the results of irrigated rotation experiment, conducted in the North West Frontier Province (NWFP), Pakistan, during 1999–2002 to evaluate effects of residues retention, fertilizer N and legumes in crop rotation on yield of maize (Zea mays L.) and soil organic fertility. Chickpea (Cicer arietinum L) and wheat (Triticum aestivum L) were grown in the winters and mungbean (Vigna radiata) and maize in the summers. Immediately after grain harvest, above-ground residues of all crops were either completely removed (−residue), or spread across the plots and incorporated by chisel plough by disc harrow and rotavator (+residue). Fertlizer N rates were nil or 120 kg ha⁻¹ for wheat and nil or 160 kg ha⁻¹ for maize. Our results indicated that post-harvest incorporation of crop residues significantly (p < 0.05) increased the grain and stover yields of maize during both 2000 and 2001. On average, grain yield was increased by 23.7% and stover yield by 26.7% due to residue incorporation. Residue retention also enhanced N uptake by 28.3% in grain and 45.1% in stover of maize. The soil N fertility was improved by 29.2% due to residue retention. The maize grain and stover yields also responded significantly to the previous legume (chickpea) compared with the previous cereal (wheat) treatment. The legume treatment boosted grain yield of maize by 112% and stover yield by 133% with 64.4% increase in soil N fertility. Similarly, fertilizer N applied to previous wheat showed considerable carry over effect on grain (8.9%) and stover (40.7%) yields of the following maize. Application of fertilizer N to current maize substantially increased grain yield of maize by 110%, stover yield by 167% and soil N fertility by 9.8% over the nil N fertilizer treatment. We concluded from these experiments that returning of crop residues, application of fertilizer N and involvement of legumes in crop rotation greatly improves the N economy of the cropping systems and enhances crop productivity through additional N and other benefits in low N soils. The farmers who traditionally remove residues for fodder and fuel will require demonstration of the relative benefits of residues return to soil for sustainable crop productivity.     

Application of an electrometric method for measurement of blood cholinesterase activities in sheep, goats and cattle treated with organophosphate insecticides

A modified electrometric cholinesterase method has been described for use in ruminants exposed to organophosphate insecticides. The method was used to measure cholinesterase activities in the plasma and erythrocytes of sheep, goats and cattle treated with organophosphate insecticides under field conditions. The animals were treated topically to control ectoparasites with malathion (0.05%) or diazinon (0.06%). The treated animals did not suffer from adverse effects related to cholinesterase inhibition. However, 2 h after treatments, plasma and erythrocyte cholinesterase activities significantly decreased in sheep by 20% and 39% and in goats by 18% and 30%, respectively, when compared with respective untreated control values. Diazinon did not significantly affect plasma and erythrocyte cholinesterase activities in the cattle. The results suggest that the described electrometric method could be efficiently used for detecting cholinesterase inhibition in ruminants exposed to organophosphate insecticides.     

Response of industrial hemp to Salsola kali subsp. tragus densities under organic and conventional fertilisation

A 2-year field study was conducted to determine the effects of different nutrition systems and Salsola kali subsp. tragus densities on industrial hemp yield and its components. Experiments were conducted as a split plot in a randomised complete block design with three replicates. Factors were fertilisation (poultry manure, vermicompost and nitrogen fertiliser) as the main plot and weed density (0, 5, 10, 15 and 20 plants/m²) as the subplot. Results indicated that the maximum number of racemes per plant, seeds per raceme, 1000-seed weight, biomass, grain yield and harvest index (HI) of industrial hemp were obtained using vermicompost and were reduced with nitrogen fertiliser application. All measured properties in hemp plants decreased due to increasing S. kali subsp. tragus density, especially at 15 and 20 plants/m². The most significant reduction in hemp grain yield and its components was observed by increasing weed density with the application of nitrogen fertiliser. The application of vermicompost at high weed densities resulted in greater hemp grain yield and its components compared with nitrogen fertiliser. It is recommended to apply organic fertilisers, especially vermicompost at high S. kali subsp. tragus densities.