Feeding gelatinized carbohydrate in the diets of magur,Clarias batrachus (Linnaeus, 1758): Effects on growth performance,enzyme activities and expression of muscle regulatory factors

This study was conducted to illustrate the effect of dietary gelatinized starch (GS) on the growth performance, enzyme activities and expression of MyoD and Myf5 in magur, Clarias batrachus fingerlings. Four iso‐nitrogenous (37%) and iso‐lipidic (6%) diets containing 15% (D‐1), 25% (D‐2), 35% (D‐3) or 45% (D‐4) GS were fed to 240 fingerlings (2.5 ± 0.5 g) in triplicates groups for 8 weeks. The maximum weight gain %, specific growth rate, protein efficiency ratio, lower FCR and higher mRNA expression of MyoD or Myf5 were found in the D‐3 group fed with 35% GS. Higher hepatosomatic index, viscerosomatic index, body lipid and lower moisture content were found in the D‐4 group. Aspartate transaminase and alanine transaminase activities were found to be higher in the D‐1 group. Amylase, glucose‐6‐phosphate dehydrogenase and blood glucose were higher in the D‐4 group. Superoxide dismutase, catalase and hexokinase activities remain unaffected by the dietary GS levels. Hence, the overall results indicate that 35% GS can improve growth performance and upregulate myogenic regulatory factors, but 45% GS level will favor lipogenesis and compromise growth. Furthermore, Myf5 gene showed more immediate response than the MyoD to the dietary carbohydrate in magur.     

Yield response of a semi-dwarf wheat variety to irrigation on a calcareous brown flood plain soil of Bangladesh

Field studies were conducted to determine the yield performance of a semi-dwarf high yielding variety of wheat (Triticum aestivum L., cv. ‘Sonalika’) in response to irrigation provided at various critical stages of growth. Determination of an irrigation schedule for most efficient water management was attempted. The study, conducted on a calcareous brown flood plain soil, comprised a randomized block design experiment with eight irrigation treatments applied at critical growth stages.The yield of wheat was the highest and the irrigation efficiency maximum, when two irrigations, totalling 9.5 cm, were given at tillering and booting stages. The quantity of irrigation water applied was calculated on the basis of deficit from field capacity level of soil water content. The lowest grain yields were obtained in treatments receiving either no irrigation or only one irrigation at the grain-filling stage. The percent increase over control (no irrigation) in grain yield, due to various irrigation treatments, ranged from 21 to 92%. The data revealed that the depletion of soil water increased as the amount of irrigation water increased.The results indicate that the present yield levels of wheat in Bangladesh can easily be increased by 50–100% by irrigating with only one-third to one-half of the water currently being used, provided it is scheduled and managed efficiently, keeping in view the need of the crops as well as the soils.     

Abiotic stresses,constraints and improvement strategies in chickpea

Chickpea (Cicer arietinum L.) is cultivated mostly in the arid and semi‐arid regions of the world. Climate change will bring new production scenarios as the entire growing area in Indo–Pak subcontinent, major producing area of chickpea, is expected to undergo ecological change, warranting strategic planning for crop breeding and husbandry. Conventional breeding has produced several high‐yielding chickpea genotypes without exploiting its potential yield owing to a number of constraints. Among these, abiotic stresses include drought, salinity, water logging, high temperature and chilling frequently limit growth and productivity of chickpea. The genetic complexity of these abiotic stresses and lack of proper screening techniques and phenotyping techniques and genotype‐by‐environment interaction have further jeopardized the breeding programme of chickpea. Therefore, considering all dispiriting aspects of abiotic stresses, the scientists have to understand the knowledge gap involving the physiological, biochemical and molecular complex network of abiotic stresses mechanism. Above all emerging ‘omics’ approaches will lead the breeders to mine the ‘treasuring genes’ from wild donors and tailor a genotype harbouring ‘climate resilient’ genes to mitigate the challenges in chickpea production.     

Quality studies in wheat

Summary Eleven wheat lines were derived by five backcrossings and five selfings with Thatcher as the recurrent and Selkirk as the donor parent during backcrossings. The lines and parents were subjected to mixogram and loaf volume studies.Out of eleven backcross lines five were similar to Thatcher, two needed longer mixing time and four were less elastic than Thatcher.Eight of eleven backcross lines had similar loaf volume profiles and two lines were, to a certain extent, similar to Thatcher in loaf volume. One line was quite different from and definitely inferior to Thatcher.It is suggested that the backcross method is a useful tool in quality breeding. In view of the fact that a backcross line with a quality quite different from the recurrent parent may appear in the population, quality evaluation at pre-release stage is strongly advocated.     

Seed longevity studies in wild type,cultivated and inter-specific recombinant inbred lines (RILs) of soybean [Glycine max (L.) Merr.]

Genetic Resources and Crop Evolution - Loss of seed viability is a serious hurdle in production and ambient seed storage of soybean. Understanding the factors affecting seed viability, and...     

An optimised protocol for molecular identification of Eimeria from chickens

Molecular approaches supporting identification of Eimeria parasites infecting chickens have been available for more than 20 years, although they have largely failed to replace traditional measures such as microscopy and pathology. Limitations of microscopy-led diagnostics, including a requirement for specialist parasitological expertise and low sample throughput, are yet to be outweighed by the difficulties associated with accessing genomic DNA from environmental Eimeria samples. A key step towards the use of Eimeria species-specific PCR as a sensitive and reproducible discriminatory tool for use in the field is the production of a standardised protocol that includes sample collection and DNA template preparation, as well as primer selection from the numerous PCR assays now published. Such a protocol will facilitate development of valuable epidemiological datasets which may be easily compared between studies and laboratories. The outcome of an optimisation process undertaken in laboratories in India and the UK is described here, identifying four steps. First, samples were collected into a 2% (w/v) potassium dichromate solution. Second, oocysts were enriched by flotation in saturated saline. Third, genomic DNA was extracted using a QIAamp DNA Stool mini kit protocol including a mechanical homogenisation step. Finally, nested PCR was carried out using previously published primers targeting the internal transcribed spacer region 1 (ITS-1). Alternative methods tested included sample processing in the presence of faecal material, DNA extraction using a traditional phenol/chloroform protocol, the use of SCAR multiplex PCR (one tube and two tube versions) and speciation using the morphometric tool COCCIMORPH for the first time with field samples.     

Construction and characterization of 3-S Lines, an alternative population for mapping studies in rice (Oryza sativa L.)

Most traits of agronomic importance in rice are quantitative in nature and are controlled by polygenes, called quantitative trait loci (QTL). Understanding the nature and effect of QTLs are important for rice breeding to achieve higher yield and stability. Single segment substitution lines (SSSLs or 3-S Lines) were developed through simple sequence repeats (SSR) marker-facilitated backcrossing methods for Hua-Jing-Xian 74 (HJX74) with the donor segment from six elite germplasm and was characterized. Complete genome survey was carried out with 258 polymorphic SSR markers. Polymorphism of the donors with the recurrent parent varied between 32.98 and 60.73% with an average of 47.81%. Japonica donors were more polymorphic than indica donors. Number of substitution segments per plant decreased with the advancement of backcross generations. In BC₂F_1, BC₃F₁, BC₃F₂ and BC₃F₃ the average number of substitution segment per plant were 12.5, 5.98, 1.69 and 1.46, respectively. Average size of substitution segments also decreased with the number of times plants were backcrossed and selfed. In BC₂F₁, BC₃F₁, BC₃F₂ and BC₃F_3, average size of the segments was 25.43, 22.38, 20.78 and 18.15 cM, respectively. The rate of reduction of segment size was more in backcross (11.99%) than selfing (7.15%) generations. Percent recovery of recurrent parent genome in BC₂F₁, BC₃F₁, BC₃F₂ and BC₃F₃ was 82.24, 92.55, 98.04 and 98.52%, respectively. A total of 111 SSSLs comprising of 43 unique types were developed in BC₃F₂ and BC₃F₃. The estimated length of the segments in SSSLs ranged from 2.00 to 64.80 cM with an average of 21.75 cM, and 6.05 to 48.90 cM with an average of 20.95 cM in BC₃F₂ and BC₃F₃, respectively. Total length of all substitution segments was 2367.5 cM that covered 704.50 cM (39.25%) of the entire rice genome. Effective development and successful utilization of 3-S Lines for analysis of QTLs and mapping of genes established the suitability of the SSR marker facilitated backcross breeding approach for 3-S Lines development and its utilization.     

Indicators of soil quality and crop productivity assessment at a long-term experiment site in the lower Indo-Gangetic plains

Deterioration of soil quality under resource-intensive modern agriculture in the face of global climate change poses a huge risk to food security. Because of the complex nature, estimators of soil quality often rely upon a limited set of soil attributes, along with statistical data reduction techniques, for developing quality indices, whilst overlooking biological aspects and regional climatic variability. This study screened the most suitable soil quality indexing approaches for a rice-oilseed-based cropping system in the lower Indo-Gangetic plains (IGP). For this, surface soil samples (0–15 cm) were collected from an ongoing long-term fertilizer experiment with a rice-mustard-sesame cropping system in the IGP. The following treatments were assessed for their effect on soil quality: T₁-control, T₂-NPK (recommended NPK doses), T₃-NPKG (NPK + in situ green manuring), T₄-NPKGB (NPK + in situ green manuring + biofertilizer) and T₅-NPKF (NPK + farm yard manure FYM). We found that total organic carbon (TOC), β-glucosidase, CaCl₂ extractable S, alkaline KMnO₄ oxidizable N, activity of urease, amidase enzyme and mean weight diameter (MWD) were sensitive key indicators of soil quality. The NPKF treatment maintained the highest soil quality status (0.80–0.91), both under productivity and environmental protection goals, owing to the availability of decomposable carbon. Regression analysis showed a better agreement of equivalent rice yield with expert opinion (EO; R² = 0.89) than principal component analysis (PCA; R² = 0.76). Finally, we found that the expert opinion approach with the nonlinear scoring function was the best tool for soil quality assessment of the region.