Genetics of Fe,Zn, β-carotene,GPC and yield traits in bread wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.) using multi-locus and multi-traits GWAS

The present study was conducted to study the genetic architecture of grain micronutrients (Zn, Fe and β-carotene contents), grain protein content and four yield traits in a spring wheat reference set comprising 246 genotypes. Phenotypic data on these traits recorded at two locations and the genotyping data for 17,937 SNP markers (obtained through outsourcing) were used for genome wide association study, which gave following results after Bonferroni correction using four methods: (1) single locus single trait analysis gave 136 marker-trait associations; (2) multi-locus mixed model gave 587 MTAs; (3) multi-trait mixed model gave 28 MTAs and (4) matrix-variate linear mixed model gave 33 MTAs. As many as 73 epistatic interactions were also detected. Keeping all the results in mind, nine most important MTAs were selected for biofortification. These markers were associated with three traits (GPC, GFeC and GYPP). These MTAs can be used in wheat improvement programs either using marker-assisted recurrent selection or pseudo-backcrossing method.     

An Analytical Solution of the One-Dimensional Steady-State Van Genuchten-Based Infiltration Equation for a Heterogeneous Soil with a Root-Water Extraction Function

Eurasian Soil Science - An analytical solution is developed for the one-dimensional steady-state infiltration equation for an inclined Van Genuchten heterogeneous soil with a sink term (i.e., with...     

免耕播种机开沟防堵单元体设计与试验

为了解决华北一年两熟区玉米秸秆覆盖地免耕播种小麦存在的秸秆覆盖量大,开沟困难,机具堵塞、功耗大等问题,该文设计了一种伸缩拨杆式开沟防堵单元体。通过正交试验和结构分析相结合的方式,确定了开沟防堵单元体的主要参数,并在玉米秸秆覆盖地进行了田间试验。试验结果表明,伸缩拨杆式开沟防堵单元体开沟能力强,防堵效果好,能够创造良好的种床,改善作业质量;与带状旋耕式开沟防堵装置相比,表层土壤扰动量减少了21.5%;在开沟深度10 cm左右时,单位面积油耗量降低了23.65%,能够减少拖拉机动力消耗。该研究对免耕播种机的推广应用具有重要意义。     

Micronutrients (Fe,Mn, Zn and Cu) balance under long-term application of fertilizer and manure in a tropical rice-rice system

Purpose

The balance of micronutrients in soils is important in nutrient use efficiency, environmental protection and the sustainability of agro-ecological systems. The deficiency or excess of micronutrients in the plough layer may decrease crop yield and/or quality. Therefore, it is essential to maintain appropriate levels of micronutrients in soil, not only for satisfying plant needs in order to sustain agricultural production but also for preventing any potential build-up of certain nutrients.

Materials and methods

A long-term fertilizer experiment started in 1969 at Central Rice Research Institute, Cuttack, Odisha, India. Using this experiment, a study was conducted to analyze the balance of micronutrients and their interrelationship. The experiment was composed of ten nutrient management treatments viz. control; nitrogen (N); N + phosphorus (NP); N + potassium (NK); nitrogen, phosphorus and potassium (NPK); farmyard manure (FYM); N + FYM; NP + FYM; NK + FYM; and NPK + FYM with three replications. Micronutrients in soil (total and available), added fertilizers and organic manures and in rice plant were analyzed. Besides, atmospheric deposition of the micronutrients to the experimental site was also calculated. A micronutrient balance sheet was prepared by the difference between output and input of total micronutrients.

Results and discussion

Application of FYM alone or in combination with chemical fertilizer increased the diethylenetriamine pentaacetate (DTPA)-extractable Fe, Mn and Zn over the control treatment. The treatment with NPK + FYM had the highest soil DTPA-extractable Fe, Mn, Zn and Cu after 41 years of cropping and fertilization. Application of chemical fertilizers without P decreased the DTPA-extractable Zn over the control while the inclusion of P in the fertilizer treatments maintained it on a par with the control. The application of P fertilizer and FYM either alone or in combination significantly increased the contents of total Fe, Mn, Zn and Cu in soil mainly due to their micronutrient content and atmospheric depositions. A negative balance of Zn was observed in the N, NP, NK and NPK treatments, while a positive balance observed in the remaining treatments. The balance of Mn was negative in all the treatments, due to higher uptake by the rice crop than its addition.

Conclusions

Long-term application of chemical fertilizers together with FYM maintained the availability of micronutrients in soil and, thus, their uptake by rice crop.

     

Growth,yield and silicon uptake of rice (Oryza sativa) as influenced by dose and timing of silicon application under water-deficit stress

Two experiments were conducted to evaluate the effects of dose and timing of silicon (Si) application on rice under limited water supply. The treatments for the first study included five Si doses (0, 75, 150, 300 and 600 kg Si ha^–1) under three soil moisture conditions (100%, 75% and 50% field capacity). For the second study, the treatments were four Si application timings [100% basal, 50% basal + 50% panicle initiation (PI), 25% basal + 75% PI and 25% basal + 50% PI + 25% heading] at the dose of 300 kg ha^–1 under the same moisture conditions. The highest number of panicle plant^–1 (14.6) and grain yield (13.6 g plant^–1) were obtained with the dose of 300 kg Si ha^–1. Similarly, an increase of 34–45% in grain yield was observed for different Si application timings compared with the control. Shoot dry matter and grain yield had positive linear relationship with shoot Si content. Grain yield and number of spikelet panicle^–1 were higher at the 300 kg Si ha^–1 dose applied as 100% basal, and hence could be a feasible option for RD57 Thai rice variety under water-deficit conditions.     

Influence of nitrogen levels and plant spacing on growth,productivity and quality of two inbred varieties and a hybrid of aromatic rice

A field investigation was conducted at the Indian Agricultural Research Institute's Research Farm during the kharif (wet) seasons of 2002 and 2003 in a split plot design with three replications, consisting of 27 treatments, namely, main plots: three varieties (PRH-10, Pusa Sugandh-3 and Pusa Basmati-1) and three plant spacings (20 × 10, 20 × 15 and 20 × 20 cm²) and sub-plots: three levels of nitrogen (0, 80 and 160 kg N ha^?1). The research results indicated that aromatic rice hybrid PRH-10 produced 33 and 6%, respectively, more grain yield than that of Pusa Sugandh-3 and Pusa Basmati-1. The appreciable higher grain yield of PRH-10 over Pusa Sugandh-3 and Pusa Basmati-1 was due to considerable improvement in most of the yield attributing characters. Application of 160 kg N ha^?1 recorded 23.7 and 26.1% more grain yield over no nitrogen application whereas it was 6.4 and 6.1% more over 80 kg N ha^?1, respectively, during first and second year of the experimentation. Wider plant spacing of 20 × 20 cm² and application of 160 kg N/ha recorded significantly higher hulling, milling and head rice recovery compared to closer spacing and zero nitrogen application.     

Evaluating bath treatment effectiveness in the control of sea lice burdens on Atlantic salmon in New Brunswick,Canada

The use of medicinal bath treatment for sea lice is becoming more common, due to increasing resistance to in‐feed treatments with emamectin benzoate. Common treatment modalities in New Brunswick, Canada, include Salmosan administered by tarpaulin or wellboat, and Paramove administered by wellboat. In this study, we assessed the effectiveness of these treatment modalities in the field between 2010 and 2015 using a web‐based sea lice data management system (Fish‐iTrends^©). Effectiveness was evaluated for adult female (AF) and for pre‐adult and adult male (PAAM) life stages separately. We also investigated the impact of variability in pretreatment lead and post‐treatment lag time on effectiveness measures. There were 1185 treatment events at 57 farms that uniquely matched our pre‐ and post‐treatment count criteria. The effectiveness of treatment modality was significantly influenced by season, pretreatment level of sea lice and by lead and lag times. In summer, Salmosan administered by tarpaulin had the greatest effectiveness on both AF and PAAM, when pretreatment levels were above 10 sea lice; whereas in autumn, the performance of treatment modalities varied significantly, depending on the pretreatment levels for the life stages. Ignoring the lead or lag time effect generally resulted in an underestimation of treatment effectiveness.     

Prevalence of latent cases of Babesia equi infection in some parts of North West India as measured by the capillary agglutination test

The prevalence of Babesia equi infection in north west India was assessed by means of the capillary tube agglutination (CA) test. The particulate antigen used in the test was potent and no cross reaction with other related haemaprotozoa was observed. The serological survey showed that from 323 horses from 3 localities there was an overall incidence of 50.1 per cent. In Haryana the incidence was 38.3 per cent in the 196 horses tested, in Uttar Pradesh it was 47.2 per cent from 72 animals and in Rajasthan it was 96.4 per cent from 55 horses.