Cross performance as influenced by selection in pure lines

1. The resultant genetic gains in cross performance due to the individual, dam family and sire family (IDS) method of index selection for increased part‐period egg number in their parent lines are described.

2. A randombred control population of known pedigree was used to measure the environmental trends.

3. Selection in pure lines resulted in concomitant improvement in the crosses for the selected as well as the correlated traits.

4. Cross performance was comparatively more than expected on the basis of mid‐parent values, indicating involvement of non‐additive gene action in the expression of cross performance.

5. Crosses responded better to independent culling level selection for egg weight than their parents.

6. Heterosis appeared to increase in later generations as compared with initial generations of selection.     

PCR-based segregation of one hybrid variety of Labeo rohita and Catla catla from their wild-types

High consumer preference together with its polyculture potential has undoubtedly driven Rohu (Labeo rohita) and Catla (Catla catla) to top the list of the most preferred fishes among the Indian major carps. Commonly found in these fishes are hybrids that can be natural or man-made. Increasing emphasis on biodiversity issues has necessitated proper stock management of these through molecular genetics techniques. Also with few morphological differences that can be used to differentiate wild types and hybrids properly, the problem demands a straightforward molecular approach. Here, we report a simple PCR-based technique that can differentiate the hybrid variety from wild types easily using three different microsatellite markers. Three sets of primers were used to amplify three different microsatellite markers from the genomic DNA isolated from pectoral fins. When the PCR products using all three primer sets were analyzed, ‘hybrid–Rohu’ could be distinguished from wild types. Whereas the hybrid–Rohu DNA yielded specific PCR products with all three primer pairs, only two PCR products were obtained either from wild-type Catla DNA (by primer sets 1 and 2) or from wild-type Rohu DNA (by primer sets 1 and 3). This study clearly demonstrates that a simple PCR-based technique will help the fish breeders and hatcheries to identify and differentiate suspected hybrid–Rohu carp from the wild types within a few hours.     

ET mapping for agricultural water management: present status and challenges

Evapotranspiration (ET) is an essential component of the water balance. Remote sensing based agrometeorological models are presently most suited for estimating crop water use at both field and regional scales. Numerous ET algorithms have been developed to make use of remote sensing data acquired by sensors on airborne and satellite platforms. In this paper, a literature review was done to evaluate numerous commonly used remote sensing based algorithms for their ability to estimate regional ET accurately. The reported estimation accuracy varied from 67 to 97% for daily ET and above 94% for seasonal ET indicating that they have the potential to estimate regional ET accurately. However, there are opportunities to further improving these models for accurately estimating all energy balance components. The spatial and temporal remote sensing data from the existing set of earth observing satellite platforms are not sufficient enough to be used in the estimation of spatially distributed ET for on-farm irrigation management purposes, especially at a field scale level (∼10 to 200 ha). This will be constrained further if the thermal sensors on future Landsat satellites are abandoned. However, research opportunities exist to improve the spatial and temporal resolution of ET by developing algorithms to increase the spatial resolution of reflectance and surface temperature data derived from Landsat/ASTER/MODIS images using same/other-sensor high resolution multi-spectral images.     

Hydraulics and salinity profile of pitcher irrigation in saline water condition

The hydraulics of pitcher irrigation in saline water condition was studied in laboratory conditions in terms of flow behaviour of pitcher, soil moisture distribution, wetting front advance and distribution of salt concentration in the soil using different pitcher making materials. The Pitcher Type 1 (PT1) made up of local soil and sand yielded the lowest mean hourly depletion ranging from 0.42 to 0.62% depending on salinity of the water used. It was followed by PT2 made up of local soil, sand and resinous material with a mean hourly depletion of 0.51-0.69% and PT3 with local soil, saw dust and sand with a mean hourly depletion of 0.91-1.02%. In all cases, with the increase in salinity level of the water used (ranging from 5 to 20 dS/m), the depletion rate and moisture content in the soil profile were found to decrease.Similarly, it was found that PT1 yielded the lowest wetting front advance and salt movement followed by PT2 and PT3. It was observed that the wetting front advance in the soil decreased with increasing salinity level of the water. The salt concentration in the soil was minimum near the pitcher and maximum at the soil surface and periphery of the wetted zone. In case of PT1, the maximum salt concentration in the soil profile ranged between 1.09 and 3.88 dS/m using water with a salinity ranging from 5 to 20 dS/m, respectively. Similarly, for PT2 the maximum salt concentration in the soil profile also ranged from 1.09 to 3.88 dS/m and for PT3 from 2.30 to 6.07 dS/m. A paired t-test revealed that the moisture as well as the salt distribution of PT3 differed significantly from PT1 and PT2 at α = 0.05. Even, if the salt concentration remained the same and the moisture content remained within field capacity for PT1 and PT2, PT1 is preferred in comparison to PT2 and PT3 as the pitcher material of PT1 is locally economically available.     

Hepatoprotective effect of Ginkgoselect Phytosome in rifampicin induced liver injury in rats: evidence of antioxidant activity

The protective effects of Ginkgoselect Phytosome((R)) (GBP) on Rifampicin (RMP) induced hepatotoxicity and the probable mechanism(s) involved in this protection were investigated in rats. Liver damage was induced in Wistar rats by administering rifampicin (500 mg/kg, p.o.) daily for 30 days. Simultaneously, GBP at 25 mg/kg and 50 mg/kg, and the reference drug silymarin (100 mg/kg) were administered orally for 30 days/daily to RMP treated rats. Levels of marker enzymes (SGOT, SGPT and SALP), albaumin (Alb) and total proteins (TP) were assessed in serum. The effects of GBP on lipid peroxidation (LPO), reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) and glutathione reductase (GR) were assayed in liver homogenates to evaluate antioxidant activity. GBP (25 and 50 mg/kg) and silymarin elicited a significant hepatoprotective activity by lowering the levels of serum marker enzymes and lipid peroxidation and elevated the levels of GSH, SOD, CAT, GPX, GR, Alb and TP in a dose dependant manner. The present findings suggest that the hepatoprotective effect of GBP in RMP induced oxidative damage may be related to its antioxidant and free radical scavenging activity.     

Soil respiration from winter wheat-based cropping systems in the US Southern Great Plains as influenced by tillage managements

This study compared soil respiration (SR) fluxes from winter wheat-based cropping systems in the US Southern Great Plains (SGP) under reduced and conventional tillage. The study consisted of four sets of paired paddocks assigned to conventional or reduced tillage with a four-year crop rotation applied over time. During the 2016–2017 study year, four sets of paired paddocks were planted to: winter wheat managed for grazing, dual-purpose (grazing and grain production), and grain-only systems of production, and winter canola. Heterotrophic SR fluxes were measured using a plant and root exclusion method on eight permanently deployed PVC cores per paddock. Fluxes from the cores were measured manually using a closed chamber connected to an infrared gas analyser on 12–13 dates during the winter wheat growing season (October through May). There were strong seasonal patterns of SR flux, with lower rates during dry and cold periods, and higher rates during warm and wet periods. Large rainfall induced pulses of SR flux were observed for both tillage systems. There was no consistent large-scale difference in SR flux between tillage treatments applied to paired paddocks. Results from this study indicate SR fluxes from winter wheat-based cropping systems are controlled more by soil environmental conditions than form of tillage.