Linkage and association mapping of wild soybean (Glycine soja) seeds germinating under salt stress

Salinity threatens soybean germination, growth and production.  The germination stage is a key period in the life of soybean.  Wild soybean contains many genes related to stress resistance that are valuable resources for the genetic improvement of soybean.  To identify the genetic loci of wild soybean that are active during seed germination under salt stress, two populations, a soybean interspecific hybrid population comprising 142 lines and a natural population comprising 121 wild soybean accessions, were screened for three germination-related traits in this study.  By using single-nucleotide polymorphism (SNP) markers with three salt tolerance indices, 25 quantitative trait loci (QTLs), 21 significant SNPs (–log₁₀(P)≥4.0) and 24 potential SNPs (3.5<–log₁₀(P)<4.0) were detected by linkage mapping and a genome-wide association study (GWAS) in two environments.  The key genetic region was identified based on these SNPs and QTLs.  According to the gene functional annotations of the W05 genome and salt-induced gene expression qRT-PCR analysis, GsAKR1 was selected as a candidate gene that responded to salt stress at the germination stage in the wild soybean.  These results could contribute to determining the genetic networks of salt tolerance in wild soybean and will be helpful for molecular marker-assisted selection in the breeding of salt-tolerant soybean.     

Germination ecology of Emex spinosa and Emex australis,invasive weeds of winter crops

Emex spinosa and Emex australis are invasive dicotyledonous weeds. The effects of various environmental factors on the germination of these weeds were investigated under laboratory and glasshouse conditions. Germination response of both species was lower at warmer temperature, and maximum germination was recorded at 20/12°C (day/night). Light stimulated germination in both species, but considerable germination also occurred under darkness. More than 80% of E. spinosa seeds germinated at pH between 6 and 9, whereas E. australis seeds germination was considerably decreased at pH 9. Emex spinosa was fairly tolerant to salinity as compared with E. australis and germination (21%) of E. spinosa occurred even at 200 mm NaCl. Both species were sensitive to osmotic stress, but E. spinosa tolerated more osmotic stress than E. australis. Temperature above 20/12°C (day/night) and low osmotic potential increased time to start germination and mean germination time (MGT), as well as decreased germination index (GI) of both species. Darkness resulted in increased MGT and decreased GI in both species when compared with 10 h photoperiod. Salt stress strongly increased time to obtain 50% germination and reduced GI of both species. In both species, an increasing burial depth decreased emergence percentage and emergence index and increased time to start emergence, although some seed emerged even at 10 cm burial depth. It was concluded that both species can germinate over a wide range of environmental conditions. However, E. australis was more sensitive under adverse environmental conditions compared with E. spinosa. This information on germination ecology may aid in developing tools and strategies for management.     

Spirulina inclusion levels in a broiler ration: evaluation of growth performance,gut integrity,and immunity

Tropical Animal Health and Production - Spirulina has been used as a food source from many years for human and animals because of its superior profile of nutrition. Spirulina (SPA) having antiviral...     

Antibiosis to Corn Earworm [Helicoverpa zea (Boddie)] by Vegetable Soybean Cultivars

Six cultivars of vegetable sovbean ( Glycine max [L.] Merr.) were evaluated in the laboratory for relative levels of antibiosis to corn earworm ( Helicoverpa zea [Boddie]). The cultivars evaluated were Fuji, Kim, Oakland, Peking, Sanga , and Toano. One plant introduction (PI 229.358) having known resistance to corn earworm and Essex , a commercial cultivar, were used as check plants. The biological data for antibiosis in a series of tests included larval weights. The results showed that cultivars Sanga, Peking , and Oakland were comparatively more susceptible while cultivars Fuji, Kim , and Toano exhibited a moderate level of leaf feeding resistance to corn earworm. The cultivars with moderate resistance can be useful in reducing corn earworm damage and cost of chemical control in vegetable soybean insect pest management systems.     

Cenchrus biflorus Roxb. (Indian sandbur), a blessing or curse in arid ecosystems: a review

Although a widely used forage plant in arid areas, Cenchrus biflorus is viewed by many scientists as an invasive weed that has a serious negative impact on agriculture and biodiversity in arid and semi‐arid environments. It has risen from insignificance as a forage and famine cereal crop to its recent status as one of the most economically destructive weeds in many regions of the world. Numerous features like high nutritional value, prolific seed production, tolerance to high temperature and prolonged drought conditions contributed greatly towards its success as a potential forage species in arid environments. But, evidence from agriculturalists shows that it is a destructive invader which disrupts cultural practices and reduces natural biodiversity. Unfortunately, limited knowledge is available about its ecology and management in natural habitats and agro‐ecosystems. In this paper, we provide a comprehensive review of its ecology, biology, agricultural impact, management and utilization. This review also provides future directions for research on C. biflorus in arid environments.     

Pot study on wheat growth in saline and waterlogged compacted soil: I. Grain yield and yield components

The information of soil compaction effects on growth and yield of crops for saline and waterlogged soils is scanty. A pot experiment was conducted on a sandy clay loam soil during 2001–2002 to study the interactive effects of soil compaction, salinity and waterlogging on grain yield and yield components of two wheat (Triticum aestivum) genotypes (Aqaab and MH-97). Compaction was achieved at 10% moisture level by dropping 5 kg weight, controlled by a tripod stand for 20 times from 0.6 m height on a wooden block placed inside the soil filled pots. Soil bulk density of non-compact and compact treatments was measured as 1.21 and 1.65 Mg m⁻³, respectively. The desired salinity level (15 dS m⁻¹) was developed by mixing the required amount of NaCl in soil before filling the pots. Waterlogging was developed by flooding the pots for 21 days both at tillering and booting stages. Compaction aggravated the adverse effect of salinity on grain yield and different yield components of both the wheat genotypes. Average reduction in grain yield was 44% under non-compact saline conditions against 76% under compact saline conditions. Similarly, the reduction was about 20% more for 100 grain weight and shoot length, 30% more for number of spikelets per spike, 37% more for number of tillers per plant, and 32% more for straw weight in compact saline treatment than in non-compact saline treatment. Compaction alone caused a reduction of 36% in grain yield. The effect of waterlogging on grain yield and yield components was mostly not changed significantly due to compaction. Rather waterlogging mitigated the effect of compaction for most of the yield components except for number of spikes per plant. Therefore, as for normal soils, the cultivation of salt-affected soils should employ implements and techniques which minimize compaction of root zone soil. The effect of soil compaction can also be minimized by light irrigations with short intervals and by using a stress tolerant crop genotype.     

Flexibility analysis of irrigation outlet structures using simulation of irrigation canal hydrodynamic model

The Upper Swat Canal (USC) System became operational in 1917–1918 in North West Frontier Province (NWFP) of Pakistan. The rehabilitation and modernization of the USC was undertaken with a view to overcoming the shortage of water supplies for irrigation. The water allowance was enhanced from 0.39 to 0.77 Ls⁻¹ ha⁻¹ in the study area. Recently, the operation and management of a secondary canal or ‘distributary’ was transferred to the Farmers Organization (FO). This distributary named ‘Chowki’ offtakes from the Maira Branch of the USC. The cultivable command area (CCA) of this distributary is 4,306 ha and it serves 1,485 beneficiaries. A management committee on Chowki Distributary was formed in 2003. This distributary consists of one main and two minor channels having twenty-eight direct outlets. The Simulation of Irrigation Canal (SIC) hydrodynamic model was used to evaluate the flexibility of Chowki Distributary. The model was calibrated at 100, 80 and 70% of the design discharge (Q _d) and it was validated at 90, 85 and 60% of the design discharge. The observed and simulated water levels were in close agreement with each other for the calibration and validation periods. The statistical analysis and paired t-test indicate that the model results are not statistically different from the measured values at 1% significance level. The simulated results of the SIC model were applied to studying flexibility of the outlet structures along the Chowki Distributary. The flexibility analysis demonstrates that poor performance is inbuilt into the system due to inadequate control over the accuracy of the crest setting during the construction of the outlets.     

Arbuscular Mycorrhizal Mediated Nutrition in Plants

ABSTRACT

Arbuscular mycorrhizae (AM) are the symbiotic fungi that predominate in the roots and soils of agricultural crop plants. The most recognized beneficial effect of these fungi is to enhance host plant uptake of relatively immobile nutrients, in particular phosphorus (P), and several micronutrients. The AM fungi absorb inorganic P either from the soluble P pools in the soil, or from insoluble forms such as rock phosphates as well as from insoluble organic sources. Recent studies show that mycorrhizal fungi would have access to rock phosphate through localized alterations of pH and/or by the production of organic acid anions that may act as chelating agents. The AM colonization also improves plant N nutrition. Generally mycorrhizal symbiosis more influences on nitrogen (N) uptake and translocation if ammonium (NH₄ ⁺) rather than nitrate (NO₃ ^?) is the nitrogen source. However, under drought stress the role of mycorrhizae in NO₃ ^? transport to the root surface may be significant as the NO₃ ^? mobility is severely restricted due to its low concentration and diffusion rate under such circumstances. However, as yet little is known about the mechanism of N uptake by the AM fungi. Uptake of micronutrients is also influenced by mycorrhizal colonization.     

Histological and haematological disturbance caused by arsenic toxicity in mice model

Histological and hematological disturbance caused by Arsenic containing water were studied in mice model. Animal were divided into four groups. Control group exposed to arsenic free distilled water and 3 treatmental group exposed to the arsenic containing water with 30, 150 and 300 ppb. Blood samples and organs were collected after 40 days. Histopathological results revealed mild to severe type of necrosis and degenerative changes in kidney and liver of arsenic feed animals. Kidney of the 300 ppb group showed severe type of necrosis and degenerative changes in distal and proximal tubules. The renocytes of proximal and distal tubules were showing hydropic and fatty degeneration. Due to degenerative changes cells were showing cytoplasmic vacoulation and cytoplasmic and nuclear blebbing. Glomeruli cells were contracted and increased the bowman's spaces. Varied degrees of changes were also observed in 30 and 150 ppb exposed group. Necrosis of hepatocytes and cytoplasmic blebbing were also observed. The sinusoidal spaces were expanded due to shrinkage and necrosis of hepatocytes. Spleenocytosis occurred in spleen and the parenchymal and mesenchymal cells were replaced by connective tissue. The lymphocytes were severely damaged by arsenic toxicity. White Blood Cells (WBCs), Red Blood Cells (RBCs) and hemoglobin level in control groups were in normal range where as level were significantly decreased with the increase dose of arsenic in the respective treatmental groups. The data was analyzed statistically and was found that significant was found among the group (p<0.05).     

Evaluating the performance of mungbean genotypes for grain yield,phosphorus accumulation and utilization efficiency

Ten mungbean (Vigna radiata R. Wilczek) genotypes were evaluated for grain yield and phosphorus (P) efficiency at adequate and deficient P in soil. Genotypes differed significantly in plant height, grain yield, P accumulation (PA), and other P-efficiency parameters at both P levels. The genotype “AEM-40/30” had maximum plant height, grain yield, and phosphorus physiological efficiency index (PPEI) under P deficiency. The genotypes were distributed into nine groups based on their relationship between total PA and grain yield at deficient P level. Moreover, genotypes were categorized into low, medium, or high efficient for each parameter by allotting index score (1, 2, or 3). Maximum cumulative index score (25) was attained by the genotypes “AEM-40/30 and AEM-20/3/87”, and genotype “AEM-30/5/8/90” scored least total index (14). The significant differences among mungbean genotypes for PA, phosphorus harvest index (PHI), PPEI, and grain yield can be exploited to select or identify P-efficient mungbean genotypes.