Genome-wide association study for spot blotch resistance in Afghan wheat germplasm

Spot blotch (SB), caused by Bipolaris sorokiniana, is a devastating disease of wheat globally, especially in South Asia and South America. Understanding the genetics of resistance to SB is important for developing breeding strategies to improve resistance. A panel of 301 genotypes from Afghanistan was phenotyped over two crop seasons using a mixture of virulent B. sorokiniana isolates and genotyped using DArTSeq to obtain genome-wide markers. Fifty genotypes (16.6%) showed disease scores less than the resistant control. Principal component analysis using the genotypic data clustered the genotypes into five different groups. Among models used for genome-wide association mapping, the multilocus mixed model, and fixed and random model circulating probability unification algorithms were most effective in identifying significant marker-trait associations (MTA). Twenty-five MTAs at p ≤ .001 were identified on chromosomes 1A, 1B, 1D, 2B, 2D, 3A, 3B, 4A, 5A, 5B, 6A, 7A, and 7D, indicating the quantitative nature of resistance to SB. Phenotypic variation explained by these markers ranged from 2.0% to 17.7%, and genomic regions on the chromosomes 1D, 2D, 3A, 3B, 4A, 5A, and 5B coincided with loci identified in previous studies. Three single nucleotide polymorphism (SNP) markers on chromosomes 1B (SNP 1113207) and 5A (SNPs 5411867 and 998276) were significant in both crop seasons as well as in the combined analysis across seasons. Marker 5411867 is close to Vrn-A1, shown to be associated with SB in previous studies. Furthermore, among known SB resistance genes, Sb2 on chromosome 5B was predicted to be significant in this panel.     

Effects of Partial and Complete Replacement of Synthetic Cryoprotectant with Carrot (Daucus carota) Concentrated Protein on Stability of Frozen Surimi

ABSTRACT

The study aimed to evaluate the effects of carrot concentrated protein (CCP) as additive on the functional and textural properties of surimi from striped catfish (Pangasianodon hypophthalmus) during six months of frozen storage (?20°C). The CCP (82.22% crude protein) was used as an additive either a lone or with a synthetic cryoprotectant (sucrose-sorbitol-sodium tri-polyphosphate). Control was made with synthetic cryoprotectant only. Molecular weight of CCP was found to be 36 kDa. After six months, the results revealed that up to 50% of synthetic cryoprotectants could be replaced by CCP during frozen storage of surimi. Biochemical parameters such as protein solubility, Ca²⁺ATPase activity, and gel strength decreased significantly (p < .05) during storage. Treatment T-3 (CCP 0.5% + 50% of synthetic cryoprotectant) maintained quality of protein significantly superior (p < .05) in respect to denaturation and other functional and sensory attributes compared to all the treatments. The microstructure images of surimi confirmed that addition of CCP modified the ice crystal growth during frozen storage. This study suggests that CCP can be a potential additive to protect protein from denaturation along with partial replacement of chemical cryoprotectants.     

Heat shock protein 70 expression in different tissues of Cirrhinus mrigala (Ham.) following heat stress

Members of heat shock protein 70 (HSP70) are highly conserved proteins of about 70 kDa and play important roles in protein folding. Levels of these proteins increase when cells are under stress. Environmental temperature influences both the basal and induced levels of HSPs. However, studies on HSPs in fishes from a tropical country such as India are lacking. In the present study, Indian major carp (IMC) Cirrhinus mrigala (Ham.) acclimatized at 25±2°C had high levels of HSP70, viz., 1.2–1.3 ng μg^?1 total protein in kidney and gill and 4.2–5.3 ng μg^?1 total protein in liver and brain tissues, indicating the presence of biochemically significant levels of stress. However, maintenance of acclimatized fish at 17°C for up to 48 h did not lead to a significant decrease in stress protein levels. A heat shock at 37°C for up to 48 h resulted in only two to threefold increase in HSP70 levels in these organs. Although the increase in HSP70 levels was apparent from the first hour of heat stress in all these tissues, the increase was significant from the second hour in the brain, the sixth hour in liver and kidney and the 20th hour in the gills.     

In vitro high frequency direct plant regeneration from whole leaves of blackberry

High frequency and direct (without callus) plant regeneration was achieved from whole leaf explants of thornless blackberry (Rubus hybrid) cv. Black Satin (EC No. 381258; PI No. 553272) in vitro. Leaf blade explants from 1-, 3- and 5-month-old mother cultures were cultured on Murashige and Skoog (MS) medium with thidiazuron (TDZ), N⁶-benzylaminopurine (BAP), indol-3-butyric acid (IBA) and α-naphthalene acetic acid (NAA), alone or in combination. Three-month explants cultured on 0.02 mg l⁻¹ TDZ produced a high regeneration frequency (91.7%) and the most shoots/leaf explant (17.3). The shoot primordia developed within 3 weeks from the point of detachment of the petiole from the leaf blade. The age of the explant source significantly affected the shoot regeneration potential of the leaf explants. Leaves excised from 3-month-old in vitro-cultured shoots performed better than those from 1- and 5-month-old shoots. Shoots rooted best on half-strength MS basal medium with 0.5 mg l⁻¹ IBA and 90% of the plantlets survived acclimatization. The regenerated plantlets were morphologically similar to the mother plants.     

Integrated effect of transplanting date, cultivar and irrigation on yield, water saving and water productivity of rice (Oryza sativa L.) in Indian Punjab: Field and simulation study

Individual effect of different field scale management interventions for water saving in rice viz. changing date of transplanting, cultivar and irrigation schedule on yield, water saving and water productivity is well documented in the literature. However, little is known about their integrated effect. To study that, field experimentation and modeling approach was used. Field experiments were conducted for 2 years (2006 and 2007) at Punjab Agricultural University Farm, Ludhiana on a deep alluvial loamy sand Typic Ustipsamment soils developed under hyper-thermic regime. Treatments included three dates of transplanting (25 May, 10 June and 25 June), two cultivars (PR 118 inbred and RH 257 hybrid) and two irrigation schedules (2-days drainage period and at soil water suction of 16 kPa). The model used was CropSyst, which has already been calibrated for growth (periodic biomass and LAI) of rice and soil water content in two independent experiments. The main findings of the field and simulation studies conducted are compared to any individual, integrated management of transplanting date, cultivar and irrigation, sustained yield (6.3-7.5 t ha⁻¹) and saved substantial amount of water in rice. For example, with two management interventions, i.e. shifting of transplanting date to lower evaporative demand (from 5 May to 25 June) concomitant with growing of short duration hybrid variety (90 days from transplanting to harvest), the total real water saving (wet saving) through reduction in evapotranspiration (ET) was 140 mm, which was almost double than managing the single, i.e. 66 mm by shifting transplanting or 71 mm by growing short duration hybrid variety. Shifting the transplanting date saved water through reduction in soil water evaporation component while growing of short duration variety through reduction in both evaporation and transpiration components of water balance. Managing irrigation water schedule based on soil water suction of 16 kPa at 15-20 cm soil depth, compared to 2-day drainage, did not save water in real (wet saving), however, it resulted into apparent water saving (dry saving). The real crop water productivity (marketable yield/ET) was more by 17% in 25th June transplanted rice than 25th May, 23% in short duration variety than long and 2% in irrigation treatment of 16 kPa soil water suction than 2-days drainage. The corresponding values for the apparent crop water productivity (marketable yield/irrigation water applied) were 16, 20 and 50%, respectively. Pooled experimental data of 2 years showed that with managing irrigation scheduling based on soil water suction of 16 kPa at 15-20 cm soil depth, though 700 mm irrigation water was saved but the associated yield was reduced by 277 kg ha⁻¹.     

Carbonic anhydrase and Na/K-ATPase activities at different molting stages of the giant freshwater prawn <Emphasis Type="Italic">Macrobrachium rosenbergii</Emphasis>

ABSTRACT:   In the present study, the role of carbonic anhydrase (CA) and Na/K-ATPase in the gill and epidermal tissues in the giant freshwater prawn Macrobrachium rosenbergii was examined as a function of molting stage. CA activity levels in the front and back gills were low at the intermolt stage C₀, but increased significantly at premolt stage D₃, and then decreased after molting. In the epidermal tissue, activity levels decreased gradually towards premolt to a minimum level at stage D₃, but became elevated at postmolt stages A and B. Na/K-ATPase levels in the front and back gills did not change significantly during the molt cycle. CA in the gill is possibly involved in supplying counter-ions for ion uptake, while CA in the epidermal tissue may play a role in mineralizing the exoskeleton after ecdysis. Na/K-ATPase in the gills may function in ion uptake from the ambient medium; however, since its activity was not influenced by the molt cycle, it probably does not have a major role in osmoregulation in the freshwater environment.     

Potential,constraints and applications of in vitro methods in improving grain legumes

Grain legumes, the important constituents of sustainability‐based cropping systems and energy‐limited vegetarian diets have long been the subject of scientific research. Tremendous technological strides were made in the so‐called orphan crops, in terms of both varietal improvement and generation of basic information. Despite recalcitrancy and high genotype dependency, in vitro culture techniques such as organogenesis, in vitro mutagenesis, embryo rescue and in vitro gene transfer have been deployed for improvement of several grain legumes and these played an important role in introgression of desirable genes from related and distant species and creation of additional genetic variability. Stable and reproducible regeneration protocols resulted in the development of genetically modified chickpea, pigeon pea, cowpea, mungbean, etc., while embryo rescue was deployed successfully for recovery of interspecific recombinants, a few of them exploited for the development of commercial cultivars. Nevertheless, doubled haploidy witnessed limited success and protoplast regeneration and in vitro mutagenesis remained of academic interest. The present review focuses on the progress, achievements, constraints and perspectives of using in vitro technology in grain legume improvement.     

Long‐term effects of fertilization on some soil properties under rainfed soybean‐wheat cropping in the Indian Himalayas

This study aims to examine the effects of long‐term fertilization and cropping on some chemical and microbiological properties of the soil in a 32 y old long‐term fertility experiment at Almora (Himalayan region, India) under rainfed soybean‐wheat rotation. Continuous annual application of recommended doses of chemical fertilizer and 10 Mg ha^–1 FYM on fresh‐weight basis (NPK + FYM) to soybean (Glycine max L.) sustained not only higher productivity of soybean and residual wheat (Triticum aestivum L.) crop, but also resulted in build‐up of total soil organic C (SOC), total soil N, P, and K. Concentration of SOC increased by 40% and 70% in the NPK + FYM–treated plots as compared to NPK (43.1 Mg C ha^–1) and unfertilized control plots (35.5 Mg C ha^–1), respectively. Average annual contribution of C input from soybean was 29% and that from wheat was 24% of the harvestable aboveground biomass yield. Annual gross C input and annual rate of total SOC enrichment from initial soil in the 0–15 cm layer were 4362 and 333 kg C ha^–1, respectively, for the plots under NPK + FYM. It was observed that the soils under the unfertilized control, NK and N + FYM treatments, suffered a net annual loss of 5.1, 5.2, and 15.8 kg P ha^–1, respectively, whereas the soils under NP, NPK, and NPK + FYM had net annual gains of 25.3, 18.8, and 16.4 kg P ha^–1, respectively. There was net negative K balance in all the treatments ranging from 6.9 kg ha^–1 y^–1 in NK to 82.4 kg ha^–1 y^–1 in N + FYM–treated plots. The application of NPK + FYM also recorded the highest levels of soil microbial‐biomass C, soil microbial‐biomass N, populations of viable and culturable soil microbes.     

Influence of crop establishment methods on yield,economics and water productivity of rice cultivars under upland and lowland production ecologies of Eastern Indo-Gangetic Plains

A field study on assessment of crop establishment methods on yield, economics and water productivity of rice cultivars under upland and lowland production ecologies was conducted during wet seasons (June–November) of 2012 and 2013 in Eastern Indo-Gangetic Plains of India. The experiment was laid-out in a split-plot design (SPD) and replicated four times. The main-plot treatments included three crop establishment methods, viz. dry direct-seeded rice (DSR), system of rice intensification (SRI) and puddled transplanted rice (PTR). In sub-plots, five rice cultivars of different groups like aromatic (Improved Pusa Basmati 1 and Pusa Sugandh 5), inbreds (PNR 381 and Pusa 834) and hybrid (Arize 6444) were taken for their evaluations. These two sets of treatments were laid-out simultaneously in two production ecologies, upland and lowland during both years. In general, lowland ecology was found favourable for rice growth and yield and resulted in 13.2% higher grain yield as compared to upland ecology. Rice grown with SRI method produced 19.4 and 7.0% higher grain yield in 2012 and 20.6 and 7.1% higher in 2013, over DSR and PTR. However, PTR yielded 13.1 and 14.5% higher grain over DSR during 2012 and 2013, respectively. On an average, Arize 6444 produced 26.4, 26.9, 28.9 and 54.7% higher grain yield as compared to PS 5, P 834, PNR 381 and IPB1, respectively. Further, the interaction of production ecologies × crop establishment methods revealed that, in upland ecology, SRI recorded significantly higher grain yield as compared to PTR and DSR, but in lowland, grain yield resulting from SRI was similar to the yield obtained with PTR and significantly higher than DSR. The latter two methods (PTR and DSR) yielded alike in lowland ecology in both study years. The production ecologies × crop establishment methods × cultivars interaction on grain yield showed that the growing of Arize 6444 cultivar using SRI method in upland ecology resulted in the higher grain yield (8.87 t/ha). But the cost of production was also highest in SRI followed by PTR and DSR across production ecologies and cultivars. Cultivation of hybrid (Arize 6444) involved higher cost of production than all other cultivars. Irrespective of crop establishment methods and cultivars, gross returns, net returns and B:C ratio were significantly higher in lowland compared to upland ecology. Owing to higher grain yield, SRI method fetched significantly higher gross returns and net returns over PTR and DSR. Average increase in net return with Arize 6444 was 68.8, 41.0, 37.7 and 33.1% over IPB 1, PNR 381, P 834 and PS 5, respectively. There was a saving of 30.7% water in SRI and 19.9% in DSR over PTR under upland ecology. Similarly in lowland ecology, water saving of 30.2% was observed in SRI and 21.2% in DSR over PTR. Due to higher yield and saving on water, SRI returned significantly higher total water productivity (TWP) (5.9 kg/ha-mm) as compared to DSR (3.5 kg/ha-mm) and PTR (3.6 kg/ha-mm) under upland ecology. In lowland ecology, also SRI (6.2 kg/ha-mm) resulted in higher TWP as compared to other two methods. However, DSR gave significantly higher TWP as compared to PTR. Among cultivars, hybrid Arize 6444 recorded the highest TWP in both upland and lowland production ecologies across crop establishment methods. Hence, growing of hybrid Arize 6444 with SRI method can enhance rice productivity and water-use efficiency in lowland and upland production ecologies of Eastern Indo-Gangetic Plains and in other similar regions.