Alterations in enzyme activities in vital organs of triploid female catfish Heteropneustes fossilis (Bloch)

Triploid Heteropneustes fossilis (Bloch) showed sterility and higher growth potential than the normal diploid fish. Activities of some metabolic enzymes such as cytosolic NADP-malate dehydrogenase (NADP-MDH), mitochondrial NAD-malate dehydrogenase (NAD-MDH) and glutamate pyruvate transaminase (GPT) were evaluated in liver, brain and kidney along with glucose-6-phosphate dehydrogenase (G-6-P D) in ovary of female triploid catfish. Activities of these enzymes showed distinct seasonal periodicity, mostly with highest activities in prespawning and spawning periods, in both diploid and triploid catfish but differed in magnitude. In triploid liver, GPT showed higher activity than the diploid counterpart in prespawning and spawning periods. On the contrary, mitochondrial NAD-MDH and cytosolic NADP-MDH in this organ showed a consistent lower activity than the diploid in all stages or in some stages of reproductive cycle respectively. Interestingly, none of the enzymes in brain and kidney of triploid female catfish showed significant changes in comparison to the diploid counterpart. The triploid ovary maintained a significantly lower level of G-6-P D activity throughout the resting, preparatory and pre-spawning periods compared to the diploid ovary. Lower level of malic enzymes (NAD-MDH and NADP-MDH) in liver and G-6-P D in ovary are in close synchrony with lower level of estradiol-17β in plasma of female triploids as found in earlier study.     

Effect of 22-Year-L​ong Conjunctive Use of Organic and Chemical Sources of Nutrients on Crop Yield,Soil Properties,and Nutrient Balance in Post-Monsoon Sorghum (Sorghum bicolor L.) in Peninsular Vertisols of India

A long-term field experiment was conducted in Vertisols of Solapur (Maharashtra, India) to assess the effect of the integrated use of nutrients on yield, soil properties, and nutrient balance in post-monsoon sorghum. The highest crop yield (1.19 Mg ha^?1) and available nutrients (308, 14.9, and 814 kg ha^?1 nitrogen (N), phosphorus (P), and potassium (K), respectively) were recorded in the treatment of 25 kg N sorghum crop residue (CR) + 25 kg N Leucaena clippings (LCs), 25 kg N (CR) + 25 kg N (urea), 25 kg N farmyard manure + 25 kg N (urea), and 25 kg N (CR) + 25 kg N (LC), respectively. Most of the nutrients were depleted except K and Ca. The response ratio for N (16 kg kg^?1) and partial factor productivity (33 kg kg^?1) were considerably higher in the 25 kg N (CR) + 25 kg N (LC) treatment. Conjunctive use of organic ?and chemical fertilizers helped in reducing the nutrient losses and improved their use efficiency and yield sustainability.     

Induction of polyploids in acid lime (Citrus aurantifolia) through colchicine treatment of in vitro derived shoot tip explants

Polyploid breeding is an effective tool to induce variability in the existing population, specifically in the crops having very narrow genetic base such as acid lime. Hence, an experiment was conducted to induce polyploidy in acid lime through colchicine treatment. Higher frequency of triploids were obtained in 250 μM colchicine treatment (27.27%), whereas combination of 3× (21.42%), 4× (13.33%) and aneuploid (6.67%) were induced at 500 μM colchicine treatment. Measurement of stomatal density and guard cell size of colchiploids revealed that the former one has negative relation with ploidy level and a positive relation was observed between guard cell size and ploidy level. Further, area and size of nuclei also had a positive relation with ploidy level. Hence, stomatal density, guard cell and nuclei size can be used effectively as morphological marker for preliminary polyploid screening. From the experiment, it can be concluded that 500 μM colchicine treatment of in vitro derived shoot tip explants of acid lime is optimum for creating maximum possible variability through polyploidization in the existing acid lime population.     

Zinc delivery to plants through seed coating with nano-zinc oxide particles

In India, zinc (Zn) has been recognized as the fourth most important yield-limiting nutrient after nitrogen (N), phosphorus (P) and potassium (K). Supplementing the zinc (Zn) requirement of agricultural crops through water soluble zinc sulfate ZnSO₄ fertilizer is a costly management option whereas, utilization of ZnO (water insoluble and a cheaper material) as a source of Zn could be an alternative cost effective option to encourage farmers for wider adoption. In this present investigation, in order to supply the requisite amount of Zn to the plants, a protocol has been developed to coat the seeds of maize (Zea mays L.), soybean (Glycine max L.), pigeon pea (Cajanas cajan L.) and ladies finger (Abelmoschus esculentus L.) with microns scale (<3 µm) and nano-scale (<100 nm) ZnO powder at 25 mg Zn/g seed and at 50 mg Zn/g seed. Different Zn sources, ethyl alcohol, and crude pine oleoresin (POR) were used for coating of seeds. The germination test carried out with coated and uncoated seeds indicated better germination percentage (93–100%) due to ZnO coating as compared to uncoated seeds (80%). Pot culture experiment conducted with coated seeds also revealed that the crop growth with ZnO coated seeds were similar to that observed with soluble Zn treatment applied as zinc sulfate heptahydrate (ZnSO₄·7H₂O) (at 2.5 ppm Zn) which is evident from the periodic SPAD reading taken after 20, 25, 30 and 45 days after sowing. Application of Zn through different sources also enhanced the auxin indole-3-acetic acid (IAA) production in plant roots, which subsequently improved the overall growth. The most important advantage of seed coating with ZnO (both micron/nano-scale) is that it did not exert any osmotic potential at the time of germination of the seed, thus, the total requirement of Zn of the crop can be loaded with the seed effectively through nano-scale ZnO particle.     

Regeneration and characterization of Swertia chirata Buch.-Ham. ex Wall. plants from immature seed cultures

First generation immature seeds (R₁) were collected from a field transferred micropropagated plant and seeds were induced to develop organogenic calli in Swertia chirata, a traditional revenue earning medicinal plant. Half strength MS medium with different growth regulators namely, BA, Kn (2.22–4.44 μM), NAA (2.69–5.37 μM), and 2.26 μM 2,4-D were used to induce callus and organogenesis. Isolated shoots produced roots either in the same medium or in presence of NAA (2.69–10.74 μM) or IBA (2.46–9.8 μM). Fully developed plantlets were successfully transplanted to soil and the fertile seed bearing plants developed. Occasionally plants derived from more than 56 weeks old calli showed some morphological variations. Such variations in regenerated plants is not reflected in their chromosomal constitution, with normal 2n = 26 chromosomes. Likewise, no variation was observed in DNA fingerprinting patterns among the short-term raised culture regenerants, which were morphologically similar to that of the donor plant illustrating their genetical uniformity and clonal fidelity. On the contrary, variation in DNA fingerprinting patterns was observed in long-term culture raised plants.     

Long-term farmyard manure application effects on properties of a silty clay loam soil under irrigated wheat–soybean rotation

Increasing importance has been placed on the use of agricultural soils for the mitigation of atmospheric CO₂ through sequestration of soil C. Although crop productivity is sustained mainly through the application of organic manure in the Indian Himalayas, little information is available on C sequestration, C content in different aggregate size fractions and soil water transmission properties (infiltration and saturated hydraulic conductivity) as affected by long-term manure addition. We analyzed results of an 8-year experiment, initiated in 1995–1996 on a silty clay loam soil, to determine the influence of fertilizer and fertilizer + farmyard manure (FYM) application on those important soil properties. The overall increase in soil organic C (SOC) content in the 0–45 cm soil depth in NPK + FYM treatment as compared to NPK and control treatments was 11.0 and 13.9 Mg C ha⁻¹ at the end of 8 years, respectively. Application of FYM significantly reduced soil bulk density and increased mean weight diameter (MWD) and SOC contents in different aggregate size fractions. Soil organic C content in macroaggregates was greater than in microaggregates. The response of SOC content to FYM application was dependent upon inorganic fertilization and more upon balanced application of NPK than N only. Steady state infiltration rate under NPK + FYM (1.98 cm h⁻¹) was higher than under unfertilized (0.72 cm h⁻¹) and NPK (1.2 cm h⁻¹). Soil water sorptivity (calculated from Philip's equation) under NPK + FYM (1.06 cm min^−0.5) was higher than under NPK (0.61 cm min^−0.5). We conclude that hill farmers in northern India should be encouraged to use FYM along with chemical fertilizers to increase SOC content and improve soil physical properties.     

Growth and evapotranspiration pattern of rajmash (Phaseolus vulgaris L.) under varying irrigation schedules and phosphate levels in a hot sub-humid climate

Soil water and phosphorus availabilities play crucial role in yield and water use pattern of pulse crops. A field experiment with rajmash (Phaseolus vulgaris L.) as a test crop was carried out during the winter seasons of 2003-2004 and 2004-2005 on a sandy loam soil (Aeric Haplaquept) in eastern India. In the main plots, irrigation was applied when the cumulative pan evaporation reached: (i) 33 mm (CPE₃₃), (ii) 44 mm (CPE₄₄) and (iii) 66 mm (CPE₆₆). In sub-plots, four levels of phosphate fertilizer were applied at: (i) 0 (P₀); (ii) 30 (P₃₀); 60 (P₆₀) and 90 kg P₂O₅ ha⁻¹ (P₉₀). Irrespective of crop growth stage, the highest leaf area index (LAI), biomass, grain yield and water use efficiency were obtained under the combination of CPE₃₃-P₉₀. Magnitude of these parameters, in general, decreased with the decrease in irrigation frequency and phosphate levels. With the advancement of crop growing period, cumulative actual evapotranspiration (CAET) increased linearly. Best matching between CAET and cumulative pan evaporation data was recorded under CPE₃₃-P₉₀ treatments. A linear relationship with high coefficient of determination was obtained between total biomass and CAET. Present study showed that crop response factor (k_y) of the crop was 1.91.     

Soil Carbon Sequestration in Long-Term Fertilization Under Jute-Rice-Wheat Agro-Ecosystem

Soil organic carbon (SOC) sequestration in response to long-term fertilizer management practices under jute-rice-wheat agro-ecosystem in alluvial soils was studied using a modeling approach. Fertilizer management practices included nitrogen (N), phosphorus (P) and potassium (K) fertilization, manure application, and root-stubble retention of all three crops. Soil carbon (C) model RothC was used to simulate the critical C input rates needed to maintain initial soil C level in long timescale (44 years). SOC change was significantly influenced by the long-term fertilizer management practices and the edaphic variable of initial SOC content. The effects of fertilizer combination “100%NPK+FYM” on SOC changes were most significant over “100%NPK” fertilization. If the 100% NPK fertilizer along with manure applied with stubble and roots retention of all crops, alluvial soils of such agro-ecosystem would act as a net C sink, and the average SOC density kept increasing from 18.18 Mg ha^?1 during 1972 to the current average of ～22 Mg ha^?1 during 2065 s. On an average, the critical C input was estimated to be 5.30 Mg C ha^?1 yr^?1, depending on local soil and climatic conditions. The critical C input could be effectively estimated using a summary model driven by current SOC level, mean annual temperature, precipitation, and soil clay content. Such information will provide a baseline for assessing soil C dynamics under potential changes in fertilizer and crop residues management practices, and thus enable development of management strategies for effectively mitigating climate change through soil C sequestration.     

Different indices to characterize water use pattern of irrigated cauliflower (Brassica oleracea L. var. botrytis) in a hot sub-humid climate of India

Frequency and depth of irrigation play crucial role in crop yield and use efficiency of water resource. To test this hypothesis a field study was carried out in November to January of 2001-2002 to 2003-2004 on a sandy loam (Aeric haplaquept) for quantifying the frequency and depth of irrigation on growth, curd yield (CY) and water use pattern of cauliflower (Brassica oleracea L. var. botrytis). Four irrigation frequencies depending on the attainment of cumulative pan evaporation (CPE) values of: 25 (CPE₂₅), 31(CPE₃₁), 38 (CPE₃₈) and 45 (CPE₄₅) mm were placed in main-plots, with three depth of irrigation (IW) of 35 (IW₃₅), 30 (IW₃₀) and 25 (IW₂₅) mm in sub-plots. Water use efficiency (WUE), net evapotranspiration efficiency (WUE_ET) and irrigation water use efficiency (WUE_I) were computed. Marginal water use efficiency (MWUE) and elasticity of water productivity (EWP) were calculated using the relationship between CY and seasonal actual evapotranspiration (SET). A continuous increasing trend in growth parameters, yield and WUE_I was recorded with the increase in SET from CPE₄₅-IW₂₅ to CPE₃₁-IW₃₀. However with further increase in SET the same decreased up to CPE₂₅-IW₃₅ regime. Highest WUE and WUE_ET obtained under CPE₃₈-IW₃₅ regime where SET value was 5% lower than the status of SET under CPE₃₁-IW₃₀. This study confirmed that critical levels of SET needed to obtain maximum curd yield or WUE, could be obtained more precisely from the knowledge of MWUE and EWP.     

Long-term yield trend and sustainability of rainfed soybean–wheat system through farmyard manure application in a sandy loam soil of the Indian Himalayas

A long-term (30 years) soybean–wheat experiment was conducted at Hawalbagh, Almora, India to study the effects of organic and inorganic sources of nutrients on grain yield trends of rainfed soybean (Glycine max)–wheat (Triticum aestivum) system and nutrient status (soil C, N, P and K) in a sandy loam soil (Typic Haplaquept). The unfertilized plot supported 0.56 Mg ha⁻¹ of soybean yield and 0.71 Mg ha⁻¹ of wheat yield (average yield of 30 years). Soybean responded to inorganic NPK application and the yield increased significantly to 0.87 Mg ha⁻¹ with NPK. Maximum yields of soybean (2.84 Mg ha⁻¹) and residual wheat (1.88 Mg ha⁻¹) were obtained in the plots under NPK + farmyard manure (FYM) treatment, which were significantly higher than yields observed under other treatments. Soybean yields in the plots under the unfertilized and the inorganic fertilizer treatments decreased with time, whereas yields increased significantly in the plots under N + FYM and NPK + FYM treatments. At the end of 30 years, total soil organic C (SOC) and total N concentrations increased in all the treatments. Soils under NPK + FYM-treated plots contained higher SOC and total N by 89 and 58% in the 0–45 cm soil layer, respectively, over that of the initial status. Hence, the decline in yields might be due to decline in available P and K status of soil. Combined use of NPK and FYM increased SOC, oxidizable SOC, total N, total P, Olsen P, and ammonium acetate exchangeable K by 37.8, 42.0, 20.8, 30.2, 25.0, and 52.7%, respectively, at 0–45 cm soil layer compared to application of NPK through inorganic fertilizers. However, the soil profiles under all the treatments had a net loss of nonexchangeable K, ranging from 172 kg ha⁻¹ under treatment NK to a maximum of 960 kg ha⁻¹ under NPK + FYM after 30 years of cropping. Depletion of available P and K might have contributed to the soybean yield decline in treatments where manure was not applied. The study also showed that although the combined NPK and FYM application sustained long-term productivity of the soybean–wheat system, increased K input is required to maintain soil nonexchangeable K level.