Yield components,light interception and marker compound accumulation of stevia (Stevia rebaudiana Bertoni) affected by planting material and plant density under western Himalayan conditions

A field experiment was conducted to study the effect of planting material and plant density on stevia (Stevia rebaudiana Bertoni) under western Himalayan conditions during 2011 and 2012. The experiment conducted in a split plot design consisted of two types of planting material (rooted slips and fresh seedlings) in the main plot and five inter- and intra-row spacing in subplots with three replications. Yield attributes and dry leaf biomass yield of stevia were not affected by the type of planting material; however, plant density significantly influenced the yield attributes and leaf and stem dry biomass. Although the wider spacing (60 × 45 cm) gave more leaves, higher leaf area index, higher leaf dry mass per plant as compared to closer spacing, it resulted in lower values of these attributes per unit area. Plants spaced in 30 × 30 cm accumulated 41.2% and 42.8% more total biomass than 60 × 45 cm. Steviol glycoside content did not change due to different planting materials and plant densities; however, closer plant spacing (30 × 30 cm) recorded 114.8% and 70.0% higher steviol glycoside accumulation compared to wider row spacing (60 × 45 cm) in 2011 and 2012, respectively.     

Socio-economic importance, domestication trends and in situ conservation of wild Citrus species of Northeast India

Northeast India is rich in Citrus genetic diversity representing several wild and cultivated species. Besides commercially cultivated species, several wild, semi-wild and domesticated species namely Citrus indica, C. macroptera, C. ichangensis, C. latipes, C. megaloxycarpa and C. assamensis are found to grow in Northeast India. These species have great potential in improvement of Indian Citrus industry being source of genes for combating biotic and abiotic stresses. The natural diversity of these genetic resources is shrinking at alarming rate due to large scale deforestation, shifting cultivation practiced in these areas and climate change scenario in this important hotspot of biodiversity. Socio-economic importance of each species have been studied during surveys and interesting domestication trends were observed based on their cultural and economic significance, which led to “in situ on farm” conservation of C. indica, C. macroptera and threat to C. megaloxycarpa and C. ichangensis. Consequently, genetic resources of most of these species are facing severe threat of extinction necessitating policy interventions and adoption of dynamic conservation and management strategies. Species specific conservation strategy especially through “in situ on farm” conservation has been proposed with suitable sites in Northeastern Indian states based on population structure and suitability of habitat. Farmers’ support through “The Biological Diversity Act, 2002” and “The Protection of Plant Varieties and Farmers’ Rights Act, 2001” of India would bring the required impact on management of these complex genetic resources of Citrus. In the present study, we have documented the current status, socio-economic potential, domestication trends and associated traditional knowledge of these wild and semi-wild Citrus species occurring in Northeast India and enumerated suitable conservation strategies and desired policy interventions for their dynamic conservation and sustainable utilization.     

Biosorption kinetics of Cu (II) ions removal from aqueous solution using bacteria

The present study highlights the effective removal of Cu (II) ions from synthetic solution using bacteria such as B. subtilis, P. aeruginosa and E. cloacae. Batch biosorption studies show that the biosorption of B. subtilis is effective when the concentration ranges from 25-200 mg L(-1). Biomass dosage, pH and the initial metal ion concentration have a profound effect on the biosorption process and this is reported in this study. In order to understand the nature of the biosorption process, Langmuir and Freundlich isotherm models were applied. Pseudo first and second order models were used to study the biosorption kinetics. The results show that these bacterial strains are very much suitable for the removal of Cu (II) ions. Being cost effective and efficient in toxic metal ion removal, these bacteria can be used on a large scale.     

Effect of Water Stress on Physiological Attributes and their Relationship with Growth and Yield of Wheat Cultivars at Different Stages

The effects of water stress on physiological attributes of drought‐sensitive (Kalyansona) and drought‐tolerant (C‐306) wheat cultivars were studied in a pot experiment. Water stress was imposed by withholding irrigation at boot and anthesis stages. Leaf water potential, leaf osmotic potential and leaf turgor potential (measured with pressure chamber and osmometer), as well as leaf diffusive resistance, leaf transpiration rate and leaf‐to‐air transpiration gradient (measured with a steady‐state porometer) were measured diurnally. Growth and yield parameters were recorded after harvesting of the crop. Triplicate data were analysed using a completely randomized design and correlations amongst these parameters were computed. Water stress was found to reduce diurnal leaf water potential and leaf osmotic potential in both the genotypes but leaf osmotic potential was significantly higher in the drought‐tolerant cultivar C‐306 than in the drought‐sensitive cultivar Kalyansona. Positive turgor was recorded in both the genotypes under water stress and non‐stress conditions. Water‐stressed plants showed significantly lower turgor potential than control plants. In diurnal observations, water‐stressed plants exhibited significantly higher leaf diffusive resistance in both genotypes at both stages. The diffusive resistance of C‐306 was predominantly higher than that of Kalyansona. Water stress decreased leaf transpiration rate at both stages but the reduction was higher at the anthesis stage. The leaf‐to‐air temperature gradient was much higher in C‐306 than in Kalyansona at the boot stage but at the anthesis stage genotypic variation was non‐significant. The capacity to maintain cooler foliage was lower at the anthesis stage than at the boot stage in both the cultivars. Shoot dry weight, number of grains, test weight, grain yield, biological yield and harvest index decreased to a greater extent when water stress was imposed at the anthesis stage, while imposition of water stress at the boot stage caused a greater reduction in plant height and number of tillers. Similarly, water stress caused a smaller reduction in growth, yield and yield attributes in C‐306 than in Kalyansona. In general, the correlation coefficient of grain and biological yield with water potential and its components was positive and highly significant. Similarly, turgor potential was also correlated positively and significantly with grain yield at both the stages, but with biological yield it was significant only at the anthesis stage. A negative and significant correlation was obtained for diffusive resistance and leaf‐to‐air temperature gradient with grain yield at the boot and anthesis stages. The rate of transpiration was also positively and significantly correlated to grain and biological yields at both the stages. Amongst the yield attributes, number of leaves and number of tillers were positively correlated at the anthesis stage, whereas leaf area and shoot dry weight were significantly correlated with grain and biological yields at both the stages.     

Productivity impacts of the system of rice intensification (SRI): A case study in West Bengal,India

The system of rice intensification (SRI) has generated considerable debate globally, particularly with regard to its potential to raise rice yields. Proponents of SRI have reported that the average rice yield with SRI is double the current average yield and can be increased to the level of three to four times. Opponents say the reported high yields are due to measurement error and that usual information expected in support of these fantastic yields is missing. The number of SRI adopters has increased in India in recent years. We evaluate the impact of adoption of SRI practices on rice yields, the economics of paddy cultivation and labour inputs based on field research conducted in Purulia, West Bengal, India. Paddy yields with SRI were higher than those under conventional paddy cultivation by 32% and net returns were higher by 67%. Labour input was reduced by 8%. SRI adoption enabled farmers consistently to enhance paddy yields, increase returns and save labour; and enhance productivity with respect to the key inputs in terms of paddy output per unit of seed, fertilizer and labour-day. SRI promises to be a significant alternative for not only raising paddy yields, but also for managing paddy based farming in resource-starved regions.     

甘蔗ATP柠檬酸裂解酶基因的克隆与表达分析

ATP柠檬酸裂解酶(ACL)为细胞质中乙酰辅酶A合成途径的关键调控酶,在生物体正常生长发育中扮演着重要角色。本研究通过Race和电子克隆技术获得编码甘蔗ACL蛋白2个亚基的基因SoACLA-1和SoACLB-1,其编码框长度分别为1 272 bp和1 827 bp,编码423个和608个氨基酸,推测的氨基酸序列与其他物种具有高度相似性,都优先与禾本科植物聚于同一进化分支。2个基因在ATP-grasp功能域、柠檬酸结合位点、组氨酸磷酸化位点和ATP结合、CoA结合、磷酸化区域等,序列高度保守。实时荧光定量PCR结果表明,2个基因均受外源ABA、水分胁迫、水分胁迫加ABA处理诱导表达,且叶中表达量显著高于根系,其中又以水分胁迫处理下的表达量最高,2个基因表现出协同表达模式。SoACLA-1和SoACLB-1的表达与ABA、ROS含量具有相关性,说明它们可能参与了ABA调控的植物对逆境胁迫反应的代谢过程。     

Genetic Relationship and Structure Analysis of Root Growth Angle for Improvement of Drought Avoidance in Early and Mid-Early Maturing Rice Genotypes

Deeper rooting 1(Dro1) and Deeper rooting 2(Dro2) are the QTLs that contribute considerably to root growth angle assisting in deeper rooting of rice plant. In the present study, a set of 348 genotypes were shortlisted from rice germplasm based on root angle study. Screening results of the germplasm lines under drought stress identified 25 drought tolerant donor lines based on leaf rolling, leaf drying, spikelet fertility and single plant yield. A panel containing 101 genotypes was constituted based on screening results and genotyped using Dro1 and Dro2 markers. Structure software categorized the genotypes into four sub-populations with different fixation index values for root growth angle. The clustering analysis and principal coordinate analysis could differentiate the genotypes with or without deeper rooting trait. The dendrogram constructed based on the molecular screening for deep rooting QTLs showed clear distinction between the rainfed upland cultivars and irrigated genotypes. Eleven genotypes, namely Dular, Tepiboro, Surjamukhi, Bamawpyan, N22, Dinorado, Karni, Kusuma, Bowdel, Lalsankari and Laxmikajal, possessed both the QTLs, whereas 67 genotypes possessed only Dro1. The average angle of Dro positive genotypes ranged from 82.7° to 89.7°. These genotypes possessing the deeper rooting QTLs can be taken as donor lines to be used in marker-assisted breeding programs.     

Role of Some Plant Growth Promotory Bacteria on Enhanced Fe Uptake of Wheat

The quest for plant growth promotory bacteria that can help in sustainable agriculture has increased in the recent years owing to increasing cost of fertilizers. In the present study, the potential of three isolated bacteria having plant growth promotory effects in mobilizing the indigenous soil iron (Fe) in two different varieties of wheat was evaluated. Three bacterial isolates belonging to the genera Burkholderia and Acinetobacter were evaluated singly and in combinations for Fe uptake of wheat in a net house study. Results showed that bacterial isolates when used in combination performed better in comparison to their individual use. These isolates significantly increased the mean Fe concentration in grains and straw by 34.0% and 52.4% over the uninoculated controls and also increased the total Fe uptake per pot in comparison to uninoculated controls. The bacterial inoculation also showed a positive impact on the bioavailability of diethylenetriaminepentaacetic acid (DTPA) extractable Fe in soil.     

Improving soil organic carbon pools through inclusion of summer mungbean in cereal-cereal cropping systems in Indo-Gangetic plain

Long-term effect of mungbean inclusion in lowland rice-wheat and upland maize-wheat systems on soil carbon (C) pools, particulate organic C (POC), and C-stabilization was envisaged in organic, inorganic and without nutrient management practices. In both lowland and upland systems, mungbean inclusion increased very-labile C (Cfrac₁) and labile C (Cfrac₂) in surface soil (0–0.2 m). Mungbean inclusion in cereal-cereal cropping systems improved POC, being higher in lowland (107.4%). Lowland rice-based system had higher passive C-pool (11.1 Mg C ha^?1) over upland maize-based system (6.6 Mg C ha^?1) indicating that rice ecology facilitates the stabilization of passive C-pool, which has longer persistence in soil. Organic nutrient management (farmyard manure + full crop residue + biofertilizers) increased Cfrac₁ and carbon management index (CMI) over inorganic treatment. In surface soil, higher CMI values were evident in mungbean included cropping systems in both lowland and upland conditions. Mungbean inclusion increased grain yield of cereal crops, and yield improvement followed the order of maize (23.7–31.3%) > rice (16.9–27.0%) > wheat (lowland 7.0–10.7%; upland 5.4–16.6%). Thus, the inclusion of summer mungbean in cereal-cereal cropping systems could be a long-term strategy to enrich soil organic C and to ensure sustainability of cereal-cereal cropping systems.     

Genetic appraisal of serological response post vaccination against enterotoxaemia (ET) in Malpura and Avikalin sheep

Tropical Animal Health and Production - Enterotoxaemia (ET) is a fatal enteric disease of small ruminants attributable to a toxigenic type of Clostridium perfringens. The key strategy for...