Heterosis for leaf photosynthesis,grain yield and yield components in maize     

Harsh Mehta  Kumud Ranjan Sarkar 《Euphytica》1992,61(2):161-168

Summary One of the primary avenues of improving the biological efficiency of crop plants is through the improvement of the leaf and canopy photosynthetic rates. However, the question whether the superiority of hybrids in respect of productivity potential could be traced, in retrospective fashion, to the photosynthetic parameters should be answered first. Once established and standardized, such indices could be streamlined in innovative breeding to predict the heterotic combinations for final yield formation. To answer this question, the photosynthetic rate and other components of photosynthetic efficiency were monitored among eight inbred stocks of maize (selected for variable photosynthetic rate from a previous study) and their all possible one-way crosses. The results demonstrated extensive heterosis in respect of photosynthetic rate and other photosynthetic indices which, in turn, was also realized in terms of higher biomass productivity and yield. Nonetheless, high leaf photosynthesis alone did not result in higher grain yield. On the contrary, component interaction among the photosynthetic indices like photosynthetic rate, leaf area/plant, number of leaves and chlorophyll content on one hand and the complementary gene action on the other, could be held responsible for higher yields in hybrids. Since the components of photosynthetic efficiency can predict heterosis for biomass and grain yield upto a reasonable extent, judicious incorporation of such indices in selection parameters for applied genetic protocols can add yet another dimension to the strategies for future yield improvements.  相似文献   

Wheat and chickpea intercropping systems in an additive series experiment: Advantages and weed smothering     

P. Banik  A. Midya  B.K. Sarkar  S.S. Ghose 《European Journal of Agronomy》2006,24(4):325-332

For increasing land use efficiency and weed suppression intercropping plays a pivotal role. A field experiment was carried out on wheat (Triticum aestivum L. emend. Fiori and Paol)–chickpea (Cicer arietinum L.) mono- and intercropping with various weeding (0, 1, or 2 hand-weeding operations) and row spacing (20- or 30-cm) treatments in the eastern plateau region of India over consecutive five winter seasons (1997/2001). The experimental design was a randomized complete block with eighteen treatments replicated thrice. Significant (P ≤ 0.05) differences were observed in yield and economics with and without weeding treatments. Chickpea yield was significantly reduced by wheat when intercropped. However, total productivity and land use efficiency were higher under the intercropping system as compared to monocrops of either species. There was a significant reduction in weed density and biomass for the intercropping system over both monocrops. Wheat facilitated an increase in nodule number and dry weight in chickpea under intercropping over monocrops, moreover, root length of chickpea was greater when intercropped. These findings suggest that intercropping wheat and chickpea increase total productivity per unit area, improve land use efficiency and suppress weeds, a menacing pest in crop production. Considering the experimental findings, wheat–chickpea (30 cm) with two weedings may be recommended for yield advantage, higher net income, more efficient utilization of resources, and weed suppression as a biological control in eastern plateau region of India.  相似文献   

Some properties of soluble proteins from alfalfa (Medicago sativa) herbage and their possible relationship to ruminant bloat.     

R E Howarth  S K Sarkar  A C Fesser  G W Schnarr 《Journal of agricultural and food chemistry》1976,25(1):175-179

  相似文献   

Investigation of Alkaline Nature of Rain Water in India     

Umesh C. Kulshrestha  Monika J. Kulshrestha  R. Sekar  M. Vairamani  Ajit K. Sarkar  Danesh C. Parashar 《Water, air, and soil pollution》2001,130(1-4):1685-1690

Increased industrialization and urbanization lead to the atmospheric acidity which causes acid rain. However, in India, the nature of rain water has been observed to be alkaline. The reason for alkaline nature of rain water is found to be the buffering of acidity by soil-derived aerosols which are rich in Ca. Over the Indian Ocean where concentrations of soil dust are negligible, the acid rain has been observed to be a common phenomenon during INDOEX campaigns. In the Indian subcontinent, observations have indicated that rain becomes acidic when the buffering potential of rain water is weak. The weak buffering potential may be due to less interference of soil dust, acidic nature of soil or very high influence of industrial source.  相似文献   

Synthesis and properties of β-d-glucosidasephenolic copolymers as analogues of soil humic-enzyme complexes     

J.M. Sarkar  R.G. Burns 《Soil biology & biochemistry》1984,16(6):619-625

Several β-d-glucosidase-phenolic copolymers were synthesized and three examined in detail: those containing l-tyrosine, pyrogallol and resorcinol. These copolymers were similar to naturallyoccurring soil humic-enzyme complexes in many ways: E₄/E₆ ratios, C, H, N and S content and IR spectra. The enzyme activity of the copolymers showed varying degrees of resistance to proteolysis, organic solvents, and storage at high temperatures. All immobilized enzymes had increased K_m values and decreased V_max values in comparison with soluble β-d-glucosidase (9.3 mM, 190μmol p-nitrophenol mg^?1h^?1); the β-d-glucosidase-resorcinol copolymer was the most active (10.5 mM, 104μmol p-nitrophenol mg^?1h^?1). β-d-Glucosidase activity was completely resistant to protease when the copolymer was fixed to bentonite clay but V_max values were reduced further (e.g. β-d-glucosidase-resorcinol-bentonite complex, 58.5μmol p-nitrophenol mg^?1 h^?1). On addition to soil, soluble β-d-glucosidase was rapidly inactivated (38% loss in 3 days, 80% loss in 21 days) whereas β-d-glucosidase-resorcinol/pyrogallol and β-d-glucosidase-L-tyrosine copolymers were comparatively stable (no loss in 9 days, 25% and 44% loss in 21 days). It is suggested that the copolymerization of enzyme during humic matter formation is a major factor leading to the stabilisation of soil enzymes and that adsorption and entrapment are comparatively insignificant.  相似文献   

Optimum plant stand and nutrient doses for summer groundnut under check basin irrigation and drip fertigation in light black soils of peninsular Western India     

Ram A. Jat  Kiran K. Reddy  Rahul Solanki  Raja Ram Choudhary  Susheel Kumar Sarkar 《Journal of plant nutrition》2020,43(8):1154-1174

Abstract

A field experiment was conducted at Research Farm of ICAR-Directorate of Groundnut Research, Junagadh for consecutive three summer seasons of 2013, 2014, and 2015 with the objectives of identifying optimum plant density and nutrient doses under check basin irrigation and drip fertigation for higher productivity and net returns. The treatments were; three plant densities viz., 3,33,333 plants/ha (100% of recommended plant density; P1); 4,16,666 plants/ha (125% of recommended plant density; P2), and 4,99,999 plants/ha (150% of recommended plant density;P3) in main plots, and three nutrient doses viz., 18.75–37.5–22.5 NPK kg ha^?1 (75% of recommended nutrient dose; F1), 25-50-30 NPK kg ha^?1 (100% of recommended nutrient dose; F2), and 31.25–62.5–37.5 NPK kg ha^?1 (125% of recommended nutrient dose; F3) in sub-plots, and replicated thrice. The same sets of treatments were tested under both check basin irrigation and drip fertigation. The data were analyzed using split plot design. Pod yield, haulm yield, and net returns were significantly higher with P3 as compared to P1 under check basin irrigation but only haulm yield was found significantly higher with P3 under drip fertigation. Under check basin irrigation, NH₄–N, NO₃–N, and available P and K in soil were found in the order P1?>?P2?>?P3 (p?<?0.05) while in case of drip fertigation, differences were significant only for available K which was significantly higher in P1 over both P2 and P3. Under check basin irrigation, F2 i.e., application of 100 percent of recommended nutrient doses, being at par with F3, significantly improved pod yield, haulm yield and net returns over that with F1 however, differences were not significant under drip fertigation. NH₄–N, NO₃–N and available P and K in soil under both the irrigation systems were in the order F3?>?F2?>?F1 (p?<?0.05).  相似文献   

The cost of postponing biodiversity conservation in Mexico     

Trevon Fuller  Patricia Illoldi-Rangel  Sahotra Sarkar 《Biological conservation》2007,134(4):593-600

Though Neotropical countries are the most species rich in the world, their biodiversity is threatened by the loss of native vegetation. Land conversion in Mexico during the last 30 years has been extensive and is representative of that of other developing countries. However, the effects of land use change on the required size and configuration of an adequate biological conservation area network are largely unknown. It is shown here that endemic mammals in Mexico could have been protected considerably more economically if a conservation plan had been implemented in 1970 than is possible today due to extensive conversion of primary habitats. Analysis of the distributions of 86 endemic mammal species in 1970, 1976, 1993, and 2000 indicates that the distributions of 90% of the species shrank during this 30-year period. At each time step, optimal conservation area networks were selected to represent all species. 90% more land must be protected after 2000 to protect adequate mammal habitat than would have been required in 1970. In addition, under a realistic conservation budget, 79% fewer species can be represented adequately in a conservation area network after 2000 compared to 1970. This provides an incentive for rapid conservation action in Mexico and other biodiversity hotspots with comparable deforestation rates, including Burma, Ecuador, Indonesia, the Philippines, and Sri Lanka. Due to ongoing habitat degradation, the efficiency of a conservation plan decreases with delays in its implementation.  相似文献   

Campylobacter infection in domestic dogs     

G B Nair  R K Sarkar  S Chowdhury  S C Pal 《The Veterinary record》1985,116(9):237-238

Campylobacter jejuni, a recently recognised human enteric pathogen, was recovered from the faeces of 21.7 per cent of domestic dogs with diarrhoea as compared with only 3.1 per cent of normal healthy dogs. The recovery rate from non-diarrhoeic, but unhealthy, domestic dogs was 6.7 per cent. The differences in the incidence of C jejuni between breeds was not statistically significant. The majority of isolations were from puppies between birth and six months old. The incidence of C jejuni in domestic dogs did not appear to be sex specific. Domestic canine infections with C jejuni could possibly be an important source of human infection, especially to those in close contact.  相似文献   

Development and characterization of light weight plant structured fabrics     

M. K. Sarkar  J. T. Fan  Y. C. Szeto  X. M. Tao 《Fibers and Polymers》2009,10(3):343-350

Scientists and engineers are increasingly turning to nature for inspiration. Light weight textile fabrics suitable for summer dress material were developed by imitating the branching structure of a plant in order to achieve high water absorption and transportation properties. The absorption property of the fabrics was characterized by using the Moisture Management Tester (MMT) and Transplanar Water Transport Tester (TWTT). The fabrics were analyzed using optical microscopes and Optical Contact Angle (OCA) tester to understand the structure as well as the absorption behavior of these fabrics. The results indicated that plant structured fabrics have a significant faster water absorption and wicking properties over conventional weave structures, makes them highly preferable for summer-wear.  相似文献   

Factors affecting minimal growth conservation of potato microplants in vitro     

Debabrata Sarkar  Prakash S. Naik 《Euphytica》1998,102(2):275-280

Combined effects of sucrose, mannitol and photoperiod on microplant conservation were studied in four potato genotypes belonging to two different groups viz., Tuberosum and Andigena. Minimal growth medium was based on Murashige and Skoog (MS) supplemented with 6 different concentrations of sucrose (30, 40, 50, 60, 70 and 80 gl^-1) with 4 different concentrations of mannitol (0, 20, 40 and 60 gl^-1). The cultures were conserved under two photoperiod conditions i.e. continuous illumination and 16-h photoperiod at 6 ± 1 °C. There were significant interactions between photoperiod and sucrose, and between photoperiod and mannitol. Maximum microplant survival and desirable microplant growth were observed under 16-h photoperiod. Sucrose alone did not improve culture viability over 30 months of storage. Inclusion of mannitol in the conservation medium increased microplant survival. Sucrose x mannitol interaction showed that sucrose was effective in enhancing microplant survival in combination with 20 or 40 gl^-1 mannitol, but not with 60 gl^-1 mannitol. Combined effect of sucrose, mannitol and photoperiod showed that optimum microplant growth and maximum culture viability were obtained when the cultures were grown in MS medium containing 40 gl^-1 sucrose and 20 gl^-1 mannitol under 16-h photoperiod. Potato microplants can be conserved in this medium and cultural conditions up to 30 months without subculturing. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献