Modification of a spatially referenced crop model to simulate the effect of spatial pattern of subsoil salinity     

Prakash N. Dixit  Deli Chen 《Computers and Electronics in Agriculture》2010,74(2):313-320

High levels of subsoil salinity limit the growth and yield of dryland cereals in the Victorian southern Mallee, Australia. Currently available crop simulation models of wheat production perform poorly in this region, presumably due to their inability to account for subsoil limitations, mainly salinity. The objective of this work was to modify a spatially referenced Water and Nitrogen Management Model (WNMM) to account for the spatial pattern of subsoil salinity, by adjusting crop water uptake, in order to explain the spatial variation in wheat yield in this area. Measurements of above-ground biomass and yield of wheat, and the profile of soil salinity (0-80 cm) were made at 40 locations across an 88 ha paddock (35.78°S, 142.98°E) in the Victorian southern Mallee. The S-shaped water stress response function for crop water uptake proposed by van Genuchten (1987) was explored to modify the WNMM by adjusting the water uptake due to salinity, which significantly improved yield simulation over the original WNMM. The improvement in the model's ability to simulate wheat yield indicates that the subsoil salinity limits crop performance in the area. The incorporation of a salinity function in spatial crop models offers potential for simulating yield across a landscape and thus practicing precision agriculture provided salinity impact is considered dynamically.  相似文献   

Control of Fusarium verticillioides,cause of ear rot of maize,by Pseudomonas fluorescens     

Siddaiah Chandra Nayaka  Arakere C Udaya Shankar  Munagala S Reddy  Siddapura R Niranjana  Harishchandra S Prakash  Hunthrike S Shetty  Carmen N Mortensen 《Pest management science》2009,65(7):769-775

BACKGROUND: Maize is one of the staple food crops grown in India. Fusarium verticillioides (Sacc.) Nirenberg is the most important fungal pathogen of maize, associated with diseases such as ear rot and kernel rot. Apart from the disease, it is capable of producing fumonisins, which have elicited considerable attention over the past decade owing to their association with animal disease syndromes. Hence, the present study was conducted to evaluate ecofriendly approaches by using a maize rhizosphere isolate of Pseudomonas fluorescens (Trev.) Mig. and its formulation to control ear rot disease and fumonisin accumulation, and also to study the capacity to promote growth and yield of maize. In vitro assays were conducted to test the efficacy of P. fluorescens as a seed treatment on seed germination, seedling vigour and also the incidence of F. verticillioides in different maize cultivars. The field trials included both seed treatment and foliar spray. For all the experiments, P. fluorescens was formulated using corn starch, wheat bran and talc powder. In each case there were three different treatments of P. fluorescens, a non‐treated control and chemical control. RESULTS: Pure culture and the formulations, in comparison with the control, increased plant growth and vigour as measured by seed germination, seedling vigour, plant height, 1000 seed weight and yield. P. fluorescens pure culture used as seed treatment and as spray treatment enhanced the growth parameters and reduced the incidence of F. verticillioides and the level of fumonisins to a maximum extent compared with the other treatments. CONCLUSION: The study demonstrates the potential role of P. fluorescens and its formulations in ear rot disease management. The biocontrol potential of this isolate is more suited for fumonisin reduction in maize kernels intended for human and animal feed. Copyright © 2009 Society of Chemical Industry  相似文献   

Response of baby corn genotypes to soil and foliar nitrogen application schedule     

Madhav Prasad Neupane  Shiv Prakash Singh  Sai Sravan Uppu 《Archives of Agronomy and Soil Science》2017,63(13):1912-1926

Responsive genotypes, timing and mode of nitrogen application are important for realizing potential yield of winter baby corn. Soil application of nitrogen is a common practice. Foliar application enhances absorption and utilization of nitrogen particularly after anthesis. We investigated combined approach in management of nitrogen for the first time including soil applications followed by foliar urea spray to enhance baby corn yield and profitability. To determine these, 2-year study conducted with three genotypes and six schedules of recommended dose of nitrogen (RDN). Growth characters, productivity traits, harvest period and yields recorded. Nitrogen content and uptake, protein content and harvest were determined. Genotype HM-4 produced 4.6% and 4.1% more cobs and corn weight over HQPM-1. Combined approach resulted higher yield attributes, yields, N uptake, protein harvest and monetary returns. RDN in 4 splits with more basal (B) dose increased cob and corn yield by 4.8% and 5.1% than 3 splits (50% B). Results suggest that HM-4 be grown using RDN 50% as B, 25% at knee height stage, 20% at tassel emergence followed by 5% foliar spray after first picking as urea solution (3%) for achieving higher yield and net returns. More studies needed under diverse conditions.  相似文献   

Inheritance of resistance in soybean PI 567516C to LY1 nematode population infecting cv. Hartwig     

Prakash R. Arelli  Lawrence D. Young  Vergel C. Concibido 《Euphytica》2009,165(1):1-4

Worldwide, cyst nematode (SCN) Heterodera glycines is the most destructive pathogen on cultivated soybean (Glycine max (L.) Merr.). In the USA yield losses in 2001 were estimated to be nearly 60 million dollars. Crop losses are primarily reduced by the use of resistant cultivars. Nematode populations are variable and have adapted to reproduce on resistant cultivars overtime because resistance primarily traces to two soybean accessions. Recently cv. Hartwig was released which has comprehensive resistance to most SCN populations. A virulent nematode population LY1 was recently selected for its reproduction on Hartwig. LY1 population originated from a mass mating of Race 2 (HG Type 1.2.5-) females with Race 5 (HG Type 1.2-) males. LY1 nematode population infects currently known sources of resistance except PI 567516C. The female indices obtained on PI 567516C and Hartwig were 7% (resistant) and 155% (susceptible), respectively. However, the genetic basis of LY1 resistance in soybean PI 567516C is not known. Resistant PI line 567516C was crossed to susceptible cultivar Hartwig to generate 105 F_2:5 families. These families together with parents, seven indicator lines and a susceptible control cv. Lee-74 were evaluated for response to LY1 nematode population in the greenhouse. Chi-square analysis showed resistance in PI567516C to LY1 was conditioned by one dominant and two recessive genes (Rhg, rhg, rhg). Chi-square value was 0.15 and P = 0.70. This information will be useful to soybean researchers for developing resistant cultivars to nematode population that infects Hartwig.  相似文献   

Plasma Concentrations of 13, 14‐Dihydro‐15‐keto‐Prostaglandin F2α, Progesterone and Cortisol During Periparturient Period in Yaks (Poephagus grunniens L.)     

M Sarkar  BC Das  BK Dutta Borah  BS Prakash 《Reproduction in domestic animals》2010,45(3):433-438

An attempt was made to determine plasma concentrations of, 13, 14‐dihydro‐15‐keto‐prostaglandin F_2α (PGFM), cortisol and progesterone during periparturient period in yak. Plasma PGFM level showed an increasing trend beginning day 5 prior to parturition (0.48 ± 0.14 ng/ml) and increased steeply thereafter to reach a peak level (17.16 ± 1.31 ng/ml) on the day of parturition. The levels, then, declined sharply on day 1 postpartum to reach 1.20 ± 0.40 ng/ml and thereafter declined gradually over the days to reach 0.28 ± 0.09 ng/ml on day 20 postpartum and this level was maintained with fluctuation within narrow limits thereafter till conclusion of the blood sampling on day 90 post‐calving. The plasma progesterone concentration on days 7 and 6 before parturition was high (2.10 ± 0.10 and 2.12 ± 0.10 ng/ml, respectively). The level then decreased gradually and abrupt fall was observed 1–2 days before parturition and became basal on day of parturition (0.24 ± 0.04 ng/ml). This basal level was maintained till the end of the blood sampling on day 90 postpartum. Plasma cortisol level showed an increasing trend beginning day 2 prior to parturition (2.36 ± 0.65 ng/ml) and increased steeply thereafter to reach a peak level (26.65 ± 5.28 ng/ml) on the day of parturition. The levels, then, declined gradually over the days and touched 2.36 ± 0.25 ng/ml on day 3 postpartum and this level was maintained with fluctuation within narrow limits thereafter till day 7 post‐calving.  相似文献   

Efficacy of Ovsynch Protocol with Antiprolactin Treatment for Timed Artificial Insemination During Non‐breeding Seasons in Yaks (Poephagus grunniens L.)     

M Sarkar  BK Dutta Borah  BS Prakash 《Reproduction in domestic animals》2010,45(3):393-398

An attempt was undertaken to investigate the efficacy of Ovsynch protocol for timed artificial insemination (TAI) with or without Norprolac (antiprolactin) treatment during non‐breeding season (winter months) in yaks (n = 25). During non‐breeding season, plasma prolactin profile has been reported high due to cold and nutritional stress. The Norprolac dose of i.m. administration was standardized for prolactin suppression. Three different doses viz. 2.5, 5.0 and 7.5 mg were attempted and the dose of 7.5 mg Norprolac i.m. per animal was found to be suitable for suppression of prolactin levels up to 30 h. Ovsynch treatment with Norprolac induced more number of oestrous symptoms per animal (4.8 vs 2.1), higher LH peak concentration (24.01 vs 16.16 ng/ml), longer duration of LH surge (6.8 vs 5.2 h) and higher conception rate (70 vs 30%) in Ovsynch plus Norprolac treated animals compared with animals treated with Ovsynch alone. Therefore, this study clearly indicates the opportunity for practical application of the Ovsynch plus Norprolac protocol for TAI in yaks during non‐breeding seasons.  相似文献   

Divergent development of testosterone secretion in male zebu (Bos indicus) and crossbred cattle (Bos indicus x Bos taurus) and buffaloes (Bubalus bubalis) during growth     

S. Gulia  M. Sarkar  Vijay Kumar  H. H. D. Meyer  B. S. Prakash 《Tropical animal health and production》2010,42(6):1143-1148

Delayed pubertal development and low fertility of Bos indicus x Bos taurus crossbred male cattle and domestic buffaloes is hardly understood hence, a sensitive enzymeimmunoassay (EIA) was developed using the second antibody-coating technique and testosterone-3-O-carboxymethyloxime-horseradish peroxidase conjugate as a label for determination of testosterone in blood plasma. The EIA was validated by standard criteria. Blood samples were collected by venipuncture from growing male cattle (Karan Fries and Sahiwal) and buffalo (Murrah) and testosterone was estimated using the EIA procedure. Plasma testosterone concentrations increased significantly (P < 0.05) with advancing age. Testosterone concentrations were significantly (P < 0.01) higher in Sahiwal males in comparison to Karan Fries males. The low testosterone levels in crossbred than Sahiwal could imply that crossbred males have either not stabilized genetically or not adapted well in Indian climatic conditions resulting in poor libido and poor semen quality. The low testosterone levels in Murrah buffalo males may be the possible reason for delayed maturity in this species. The direct, sensitive EIA validated for estimating the plasma testosterone concentration was reliable for studying the testosterone profile in blood plasma of males. The results suggest that there could be a requirement for higher testosterone secretion by males during early stages of growth for attaining early sexual maturity.  相似文献   

Seasonal variations in plasma glucocorticoid levels in yaks (<Emphasis Type="Italic">Poephagus grunniens L</Emphasis>.) (<Emphasis Type="Italic">Bos grunniens</Emphasis>)     

M. Sarkar  S. Bandyopadhyay  G. Krishnan  B. S. Prakash 《Tropical animal health and production》2010,42(3):421-424

The changes of glucocorticoid concentrations were measured by highly sensitive enzymeimmunoassay procedures using second antibody coating technique and cortisol -HRP amplified system for one whole calendar year in yaks. The year was divided into seasons of cool, intermediate and hot seasons. The glucocorticoid values were lower (P < .01) in hotter months than in cool and intermediate seasons. Rectal temperature and respiration rates were indicative of heat stress in the hot temperature season and gave significant negative correlation with circulating corticoid concentration.  相似文献   

Catastrophic collapse of Indian white-backed Gyps bengalensis and long-billed Gyps indicus vulture populations     

V. Prakash  A.A. Cunningham  N. Prakash  R. Gargi  A.R. Rahmani 《Biological conservation》2003,109(3):381-390

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Cytoplasm Influences the Photosynthetic Efficiency in Brassica carinata     

D. C. Uprety    Shyam  Prakash V. K. Tomar 《Journal of Agronomy and Crop Science》1990,165(2-3):207-210

Cytoplasmic effects on the photosynthesis was investigated in experimentally produced Brassica carinatas of reciprocal cytoplasmic origin. These are obtained by hybridizing B. nigra x B. oleracea var. italica ( B. carinata 226) and B. oleracea x B. nigra ( B. carinata 241). Natural B. carinata and the two parents viz. B. nigra and B. oleracea var. italica were also included in this study. It was observed that the rate of photosynthesis in B. carinata 226 with nigra cytoplasm, and natural B. carinata was higher than that of B. carinata 241 with oleracea cytoplasm. This was substantiated by the diurnal values of photosynthesis among these cultivars. The result indicated that the cytoplasm does affect the rate of photosynthesis in B. carinata and high photosynthetic efficiency in natural B. carinata was due to B. nigra maternal parent.  相似文献