Tree row spacing affected agronomic and economic performance of Eucalyptus-based agroforestry in Andhra Pradesh, Southern India   总被引：1，自引：1，他引：0  

J. V. N. S. Prasad  G. R. Korwar  K. V. Rao  U. K. Mandal  C. A. R. Rao  G. R. Rao  Y. S. Ramakrishna  B. Venkateswarlu  S. N. Rao  H. D. Kulkarni  M. R. Rao 《Agroforestry Systems》2010,78(3):253-267

The 3 × 2 m spacing currently used for eucalyptus plantations in the state of Andhra Pradesh, southern India does not permit intercropping from the second year. This discourages small landholders who need regular income from taking up eucalyptus plantations and benefiting from the expanding market for pulpwood. Therefore, on-farm experiments were conducted near Bhadrachalam, Khammam district (Andhra Pradesh) for over 4 years from August 2001 to November 2005 to examine whether wide-row planting and grouping of certain tree rows will facilitate extended intercropping without sacrificing wood yield. Eucalyptus planted in five-spatial arrangements in agroforestry [3 × 2 m (farmers’ practice), 6 × 1 m, 7 × 1.5 m paired rows (7 × 1.5 PR), 11 × 1 m paired rows (11 × 1 PR) and 10 × 1.5 m triple rows (10 × 1.5 TR)] was compared with sole tree stands at a constant density of 1,666 trees ha^?1. Cowpea (Vigna unguiculata) was intercropped during the post-rainy seasons from 2001 to 2004, and fodder grasses (Panicum maximum and Brachiaria ruziziensis) were intercropped during both the seasons of 2005. At 51 months after planting, different spatial arrangements did not significantly affect height and diameter at breast height (dbh). Total dry biomass of eucalyptus in different spatial arrangements ranged between 59.5 and 52.9 Mg ha^?1, the highest being with 6 × 1 m and the lowest with 10 × 1.5 TR, but treatment differences were not significant. The widely spaced paired row (11 × 1 PR) and triple row (10 × 1.5 TR) arrangements produced 62–73% of sole cowpea yield in 2003, 59–66% of sole cowpea yield in 2004, and 79–94% of sole fodder in 2005. In contrast, the 3 × 2 m spacing allowed only 17–45% of sole crop yields in these years. The better performance of intercrops in widely spaced eucalyptus was likely because of limited competition from trees for light and water. Intercropping of eucalyptus in these wider rows gave 14% greater net returns compared with intercropping in eucalyptus spaced at 3 × 2 m, 19% greater returns compared with that from sole tree woodlot and 263% greater returns compared with that from sole crops. Therefore, in regions where annual rainfall is around 1,000 mm and soils are fairly good, eucalyptus at a density of 1,666 plants per ha can be planted in uniformly spaced wide-rows (6 m) or paired rows at an inter-pair spacing of 7–11 m for improving intercrop performance without sacrificing wood production.  相似文献   

Modulation of manganese toxicity in Pisum sativum L. seedlings by kinetin     

Savita Gangwar  Vijay Pratap Singh  Sheo Mohan Prasad  Jagat Narayan Maurya 《Scientia Horticulturae》2010

In the present study, the effects of kinetin (KN; 10 and 100 μM) application under manganese toxicity (Mn; 50, 100 and 250 μM) were investigated, on growth, photosynthetic pigments, total protein, total nitrogen, ammonium (NH₄⁺) content, NH₄⁺ assimilating enzymes and antioxidant system in pea seedlings. The exposure of pea seedlings to Mn and 100 μM of KN alone and in combination, caused decrease in growth, photosynthetic pigments, total protein and total nitrogen contents, and an increase in NH₄⁺ content. However, application of 10 μM of KN together with Mn reduced the Mn toxicity symptoms, promoted the growth of seedlings and led to the decrease in NH₄⁺ content compared to Mn treatments alone. The root and shoot activities of glutamine synthetase (GS), glutamate oxoglutarate aminotransferase (GOGAT) and catalase (CAT) were decreased while glutathione reductase (GR) and dehydroascorbate reductase (DHAR) activities exhibited differential responses when pea seedlings were exposed to Mn and 100 μM of KN. However, under similar treatments, activities of glutamate dehydrogenase (GDH), superoxide dismutase (SOD) and ascorbate peroxidase (APX) in root and shoot were increased. It was noticed that addition of 10 μM of KN together with Mn, caused significant stimulation in activities of enzymes of NH₄⁺ assimilation and antioxidant defense system even over their respective control values. Non-enzymatic antioxidants (ascorbate and glutathione) in root and shoot of pea seedlings exposed to Mn stress were significantly increased by the addition of 10 μM of KN. Therefore, ameliorative effect of 10 μM of KN against Mn toxicity was observed. This study thus suggests that 10 μM of KN appreciably improves Mn tolerance of pea seedlings under Mn toxicity while reverse effects were exhibited by 100 μM of KN.  相似文献   

Modeling the invasive emerald ash borer risk of spread using a spatially explicit cellular model   总被引：1，自引：0，他引：1  

Anantha M. Prasad  Louis R. Iverson  Matthew P. Peters  Jonathan M. Bossenbroek  Stephen N. Matthews  T. Davis Sydnor  Mark W. Schwartz 《Landscape Ecology》2010,25(3):353-369

The emerald ash borer (EAB, Agrilus planipennis) is decimating native ashes (Fraxinus sp.) throughout midwestern North America, killing millions of trees over the years. With plenty of ash available throughout the continent, the spread of this destructive insect is likely to continue. We estimate that the insect has been moving along a “front” at about 20 km/year since about 1998, but more alarming is its long-range dispersal into new locations facilitated by human activities. We describe a spatially explicit cell-based model used to calculate risk of spread in Ohio, by combining the insect’s flight and short-range dispersal (“insect flight”) with human-facilitated, long-range dispersal (“insect ride”). This hybrid model requires estimates of EAB abundance, ash abundance, major roads and traffic density, campground size and usage, distance from the core infested zone, wood products industry size and type of wood usage, and human population density. With the “insect flight” model, probability of movement is dependent on EAB abundance in the source cells, the quantity of ash in the target cells, and the distances between them. With the “insect-ride” model, we modify the value related to ash abundance based on factors related to potential human-assisted movements of EAB-infested ash wood or just hitchhiking insects. We attempt to show the advantage of our model compared to statistical approaches and to justify its practical value to field managers working with imperfect knowledge. We stress the importance of the road network in distributing insects to new geographically dispersed sites in Ohio, where 84% were within 1 km of a major highway.  相似文献   

Molecular evidence supports hypervariability in Phytophthora colocasiae associated with leaf blight of taro     

Vishnu Sukumari Nath  Muthukrishnan Senthil  Vinayaka Mahabaleswar Hegde  Muthulekshmi Lajapathy Jeeva  Raj Shekhar Misra  Syamala Swayamvaran Veena  Mithun Raj 《European journal of plant pathology / European Foundation for Plant Pathology》2013,136(3):483-494

The oomycete Phytophthora colocasiae that causes taro leaf blight is the most devastating disease of taro and is widely distributed worldwide. Molecular and phenotypic techniques were employed for assessing and exploiting the genetic variability among four populations of P. colocasiae obtained from a fine spatial scale (multiple leaf blight lesions on single taro leaf). Phenotypic characters such as virulence, morphology and mating type showed no variation. ITS characterization revealed detectable polymorphism among isolates of P. colocasiae. The mean number of haplotypes (H), haplotype diversity (HD), nucleotide diversity (π), and nucleotide substitution rate (θ) among analyzed sequences were 6.75, 1.00, 0.069, and 0.088 respectively. High levels of inter and intra specific variation were detected by random amplified polymorphic DNA (RAPD) assays. Moderate genetic diversity (H?=?0.2651) was observed among populations of P. colocasiae. Analysis of molecular variance (AMOVA) confirmed that most of the genetic variability was confined to within a population (63.54 %). The coefficient of genetic differentiation among populations (G _ST ) was 0.2007 and estimates of gene flow (Nm) among populations was 1.991 migrants per generation. Cluster analysis using UPGMA revealed that individuals from the same population failed to cluster in one distinct group. The results of the study reveal considerable genetic diversity among and within populations of P. colocasiae obtained from fine spatial scale. The possible mechanisms and implications of this genetic variation are discussed.  相似文献   

Micropropagation of Darjeeling orange (Citrus reticulata Blanco) by shoot-tip grafting     

S. Mukhopadhyay  Jaishree Rai  B. C. Sharma  Anita Gurung  R. K. Sengupta  P. S. Nath 《The Journal of Horticultural Science and Biotechnology》2013,88(3):493-499

Summary

Micropropagation of Darjeeling orange (Darjeeling mandarin) was done by shoot-tip grafting on the local rootstocks rough lemon, sour orange and Rangpur lime. Seedlings of these plants were raised in MS medium in standard conditions of temperature, light duration and plant age. Microbuds (0.2 mm long), aseptically excised from the scion, were grafted onto the decapitated rootstock seedlings. The micrografts in culture medium were grown under standard lighting. Rootstock seedlings showed optimum growth at 25–30°C. Optimum growth of the micrografts resulted from treatment in complete darkness for 4 d after grafting followed by exposure to 750 W for 16 h d^?1 for 15 d and 1500–2000 W for 16 h d^?1 for 39 d. The success of micrografting depended on the age of the rootstock seedling which was 21 d, 14 d and 14 d for sour orange, rough lemon and Rangpur lime respectively. The micrografts were then double grafted to the two year old rootstocks seedlings of the respective species and the age of the micrografts for the successful double grafts was also standardized. The survival rate was high with 40 d, 45 d and 45 d micrografts on sour orange, rough lemon and Rangpur lime respectively. The double-grafts were then indexed for tristeza virus and greening disease after six months’ growth in an insect-proof screenhouse and found to be free from these graft transmissible diseases.  相似文献   

Lack of evidence for an association between MHC diversity and the development of bovine neonatal pancytopenia in Holstein dairy cattle     

Ballingall KT  Nath M  Holliman A  Laming E  Steele P  Willoughby K 《Veterinary immunology and immunopathology》2011,141(1-2):128-132

Bovine neonatal pancytopenia (BNP), a disease of neonatal calves, has been described in a number of European countries since 2006. The disease results in high mortality of calves aged 1-4 weeks and is characterised by severe bone marrow pathology resulting in profound thrombocytopenia and consequent haemorrhagic diathesis. A number of hypotheses including a novel virus infection, plant toxins, a vaccine associated isoimmune disease, or a genetic defect have been suggested to explain the aetiology of this disease. However, as the number of cases in affected herds remains small, it is hypothesised that the genetic background of the calf may influence disease susceptibility. To test this we focused on the class II region of the major histocompatibility complex (MHC) which is often associated with variations in immune response and susceptibility to antibody mediated autoimmune disease. Forty-three cases of BNP and sixty-eight controls were genotyped at the polymorphic class II MHC-DRB3 locus. Twenty DRB3 alleles were identified with seven appearing at frequencies ≥ 0.05. A comparison of the allelic frequencies between diseased and control groups showed that there was no evidence for any significant differences, suggesting that the MHC does not appear to be a predisposing risk factor in the development of BNP in Holstein dairy cattle.  相似文献   

Evaluation of the antioxidant activity of capsiate analogues in polar, nonpolar, and micellar media     

Reddy KK  Ravinder T  Prasad RB  Kanjilal S 《Journal of agricultural and food chemistry》2011,59(2):564-569

Synthesis of 10 capsiate analogues was conducted by lipase-mediated (Novozyme 435) esterification of vanillyl alcohol with different fatty acids. The antioxidant activity of the synthesized capsiates was evaluated using three in vitro assays: DPPH radical scavenging assay (polar medium), Rancimat assay (nonpolar medium), and autoxidation of linoleic acid (micellar medium). The objective of this study is to find the influence of structural characteristics of the alkyl chain of capsiate analogues on their antioxidant activity. In these assays, BHT and α-tocopherol were used as reference compounds. Both DPPH and Rancimat assays did not show any specific trend of antioxidant activity with the increase in lipophilicity and also with the type of fatty acids grafted to the phenolic moiety. In the Tween 20 micellar system for the inhibition of autoxidation of linoleic acid, vanillyl ester attached to a C18 alkyl chain (vanillyl stearate, oleate, and ricinoleate) exhibited maximum inhibition of autoxidation of linoleic acid.  相似文献   

ZINC-COATED UREA IMPROVES PRODUCTIVITY AND QUALITY OF BASMATI RICE (ORYZA SATIVA L.) UNDER ZINC STRESS CONDITION     

Yashbir Singh Shivay  Rajendra Prasad 《Journal of plant nutrition》2013,36(6):928-951

A field study conducted for two years (2006 and 2007) at the Research Farm of the Indian Agricultural Research Institute, New Delhi, India showed that zinc (Zn) fertilization increased yield attributes, grain and straw yield, enhanced Zn concentrations and its uptake and improved kernel quality before and after cooking in basmati rice ‘Pusa Sugandh 5’. A 2% Zn-coating with zinc sulfate (ZnSO₄·7H₂O) was found to be the best but a 2% Zn-coating with zinc oxide (ZnO) was very close to it in terms of grain and straw yield and Zn concentrations in basmati rice grain and straw under Zn stress conditions. Partial factor productivity (PFP) of applied Zn varied from 984–3,387 kg grain kg Zn^?1, agronomic efficiency (AE) varied from 212–311 kg grain kg^?1 Zn (applied) and physiological efficiency (PE) of Zn varied from 6,384–17,077 kg grain kg^?1 Zn (absorbed). Thus, adequate Zn fertilization of basmati rice can lead to higher grain yield and Zn-denser grains with improved cooking quality in basmati rices under Zn stress soil conditions.  相似文献   

Balanced and integrated nutrient management for enhancedand economic food production: case study from rainfed semi-arid tropics in India     

Girish Chander  Suhas P. Wani  Kanwar L. Sahrawat  Prasad J. Kamdi  Chitendra K. Pal  Dilip K. Pal 《Archives of Agronomy and Soil Science》2013,59(12):1643-1658

Soil degradation in the semi-arid tropics (SAT) is mainly responsible for low crop and water productivity. In Madhya Pradesh and Rajasthan states in India, the soil analyses of farmers’ fields revealed widespread deficiencies of S (9–96%), B (17–100%) and Zn (22–97%) along with that of P (25–92%). Soil organic C was deficient in 7–84% fields indicating specifically N deficiencies and poor soil health in general. During on-farm evaluations in rainy seasons 2010 and 2011, the soil test based addition of deficient nutrient fertilizers as balanced nutrition (BN) increased crop yields by 6–40% (benefit to cost ratios of 0.81–4.28) through enhanced rainwater use efficiency. The integrated nutrient management (INM), however, decreased the use of chemical fertilizers in BN by up to 50% through on-farm produced vermicompost and recorded yields at par or more than BN with far better benefit to cost ratios (2.26–10.2). Soybean grain S and Zn contents improved with INM. Applied S, B, Zn and vermicompost showed residual benefits as increased crop yields for succeeding three seasons. Hence, results showed INM/BN was economically beneficial for producing more food, while leading to resilience building of SAT production systems.  相似文献   

Analysis of relationship between crop growth parameters,yield and physical environment within the crop canopy of sesame (Sesamum Indicum) at different sowing dates: Untersuchung der beziehungen zwischen wachstumsparametern,ertrag und physischer umwelt im pflanzenbestand von sesam (Sesamum Indicum) bei verschiedenen aussaatterminen     

R Nath  PK Chakraborty  P Bandopadhyay  CK Kundu  A Chakraborty 《Archives of Agronomy and Soil Science》2013,59(6):677-682

Relation between crop growth parameters of sesame (Sesamum indicum) and the physical environment within the crop canopy at different sowing dates was studied during the summer seasons of 1999 and 2000. The maximum leaf growth rate (LGR) and leaf area index (LAI) was obtained from February 19 sown crop. About 34.4% variation in LGR could be explained through the variation in the physical environmental elements within the crop canopy. The LAI was depressed in the later months of sowing. The February 19 sown crop produced significantly, the highest dry matter production (DMP) in all the stages of crop growth. The regression model indicated that the crop growth rate (CGR) was adversely affected by the ambient temperature and photosynthetic active radiation (PAR) within the crop canopy. Crops sown on 19 February and 1 March produced statistically similar yields. The cultivar Rama produced higher yields than B-67 and Kanke-1. Regression models suggested that the temperature profile and PAR within the crop canopy produced 69 and 39% variation in yield, respectively.  相似文献