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...     

Muscle fiber types,growth and development in the whole myotome of cultured Pacific bluefin tuna Thunnus orientalis

Following the successful development of Pacific bluefin tuna (PBT) aquaculture, it is of considerable importance to determine the muscle fiber types and their growth patterns for future development. Muscle fiber profiles of dorsal ordinary, lateral ordinary (LO) and dark muscles and their growth patterns in PBT from 3.0 to 54.3 kg body weight were studied. Muscle fibers were histochemically stained for NADH-diaphorase and myosin adenosine triphosphatase activity (mATPase), and immunohistochemically stained with S-58 slow-muscle myosin antibody. All muscle fibers in dorsal and LO muscles showed low NADH-diaphorase activity, and acid-labile (pH 4.0 or 4.3) and alkali-stable mATPase activity. In LO muscle adjacent to dark muscle, three intensities of mATPase activity were observed after acid pre-incubation at pH 4.5 or 5.0, and the activity was related to the muscle fiber diameter. In dark muscle, all small and some large fibers stained intensely for NADH-diaphorase activity, related to their high aerobic metabolism. The high-active fibers with NADH-diaphorase in dark muscle were positive for S-58 antibody. Some large fibers in dark muscle showed intermediate NADH-diaphorase activity and high mATPase activity after alkali pre-incubations. These are fast-twitch oxido-glycolytic fibers in dark muscle and transformed to red muscle fibers with increasing body weight.     

Quality of potato tubers as affected by freezing: I. texture,ascorbic acid and enzymatic discoloration

The effect of freezing on the turgor, ascorbic acid content and enzymatic discoloration of Katahdin and Atlantic potatoes was studied. Tubers were exposed to a temperature of ?20°C for 24 hrs. then thawed for 1 hr. at 20°C before analysis. Frozen tubers were then compared with unfrozen controls. Both varieties lost turgor following freezing and exuded a sticky liquid with increased thawing time. At the end of 3 hrs. thawing, a sponge-like texture was observed in both varieties. In both varieties freezing resulted in a significant reduction (p<.01) in ascorbic acid and phenolic content (p<.01). Enzymatic discoloration was also significantly reduced (p<.01) in both varieties.     

Variation in sensitivity to streptomycin-induced bleaching and dark-induced senescence of rice (<Emphasis Type="Italic">O. sativa</Emphasis>) and ragi (<Emphasis Type="Italic">E. coracana</Emphasis>) genotypes and their relationship with yield and adaptability

Variation in streptomycin sensitivity and dark sensitivity of 36 rice genotypes of three different maturity groups and 30 ragi genotypes of two different maturity groups were studied. Streptomycin sensitivity and dark sensitivity of rice and ragi genotypes were expressed in terms of bleaching index (BI) and senescence index (SI), respectively. Genotypes of each maturity group of each crop showed wide variation in their BI / SI values. The objective of this investigation was to find the relationship of the BI / SI parameter with yield, adaptability, and stability in yield performance of rice and ragi genotypes. Yield performance of rice and ragi genotypes were evaluated over 12 and nine environments, respectively. Adaptability and stability analysis were done following the linear regression model of Eberhart and Russell (1966) and the AMMI Stability Value (ASV) of Purchase (1997). BI parameter showed a positive correlation with yielding ability and deviation from regression (S2d) in both rice and ragi, and a negative correlation with adaptability parameter (b) for all the maturity groups of rice and ragi except in the early ragi group. SI parameter showed a negative correlation with yielding ability for all the maturity groups of rice and ragi except in the early ragi group and a positive correlation with adaptability parameter (b) for all the maturity groups of rice and ragi. This experimental study revealed that sensitivity of rice genotypes to streptomycin (SM) in terms of BI could be used to predict yielding ability of genotypes, and dark sensitivity (SI) could be used to indicate adaptability to rich and poor environments. This novel approach may help the breeder in indirect selection of high-yielding genotypes and genotypes well-adapted to rich or poor environments at an early seedling stage before going for multilocation trials.     

Compatibility of silver barb Puntius gonionotus (Bleeker) with Indian major carps in a grow-out polyculture

The compatibility and growth performance of silver barb Puntius gonionotus (Barbonymous gonionotus) with the three Indian major carps, i.e., Catla catla, Labeo rohita and Cirrhinus mrigala, were assessed in a 10‐month carp polyculture trial. Treatments T‐1, T‐2, T‐3 and T‐4 were stocked with three of the above four carp species, with an absence of silver barb, mrigal, rohu and catla, respectively, while all four species were stocked in treatment T‐5. The treatments were stocked at 6000 fingerlings ha⁻¹, with an equal species ratio maintained in each treatment. Incorporation of silver barb into the polyculture system neither affected the survival of any carp irrespective of species combination nor yielded significant changes in biomass production among treatments, except for the one without catla, where it was significantly low. The study revealed a higher extent of competition between silver barb and rohu, perceptible from the lower growth of one in the presence of the other. Although a certain level of competition of silver barb with mrigal was evident, competition with catla was not perceptible. Irrespective of species combination with silver barb as a component species, similar total biomass production in treatments revealed the feasibility of its incorporation into the Indian major carp‐based polyculture practice without affecting the total yield.     

Enhanced growth and immuno‐physiological response of Genetically Improved Farmed Tilapia in indoor biofloc units at different stocking densities

An experimental trial was conducted for 90 days to evaluate the growth performance, immunophysiological response of GIFT strain of Tilapia in biofloc‐based rearing system and to assess the relative percentage survival in 3 days after challenging with the virulent strain of Aeromonas hydrophila. Fingerlings with an average body weight 0.98 ± 0.06 g were stocked in triplicate at different stocking densities of 200 (SD1), 250 (SD2), 300 (SD3) and 350 (SD4) m^?3 in biofloc‐based treatments and 150 (C) m^?3 in control (clear water). Biofloc‐based units (SD1 and SD2) obtained significantly better (P < 0.05) growth performances at the end of the experimental period. Mean body weight of fish in biofloc‐based units showed a decreasing trend with increase in stocking density with 100% survival in all units including control. The stress parameters were significantly lower in biofloc‐based rearing units especially in treatments SD1 and SD2 as compared to the control. The fish from the biofloc‐based units (SD1 and SD2) possessed significantly (P < 0.05) higher immune status as compared to control and other biofloc treatments in terms of respiratory burst, serum lysozyme and myeloperoxidase activity. Relative survival percentages were significantly better in biofloc treatments with highest in SD1 and SD2 (83.33%) after challenge study. GIFT strain of Tilapia at higher stocking densities 200–250 nos m^?3 can be taken as optimum stocking density whereas higher stocking densities up to 350 nos m^?3 can be reared in the biofloc systems without compromising the growth and immunity.     

Use of Rotenone as Piscicide: Toxicity Levels in a Few Common Freshwater Predatory and Weed Fishes

Toxicity of rotenone was studied in a few common freshwater predatory and weed fishes through wet laboratory experiments for its use as a piscicide during pond preparation. Cube root powder (CRP) (ENT-133 Rotenone) containing 9% rotenone was used as the toxicant source. Lethal concentration of CRP for these common predatory and weed fishes varied between 0.75–2.70 mg L^?1 (0.068–0.243 mg L^?1 of rotenone). Acute toxicity study revealed Puntius sophore to have more susceptibility to rotenone toxicity with 24 h LC₅₀ value of CRP at 0.50 mg L^?1 (0.045 mg L^?1 rotenone) compared to 1.17 mg L^?1 (0.105 mg L^?1 rotenone) in Anabas testudineus and 1.90 mg L^?1 in Channa punctatus (0.171 mg L^?1 rotenone); while Heteropneustes fossilis showed higher tolerance with 24 h LC₅₀ value at 2.42 mg L^?1 (0.218 mg L^?1 rotenone). Such result suggested rotenone toxicity to depend on the respiratory behavior of fish. The marginal reduction in 48 h LC₅₀ of CRP compared to its 24 h value and no fish mortality beyond 48-h in all tested species suggested faster degradation of the toxicant in water. Since application of the piscicide aims at eradication of all commonly available species of predatory and weed fishes in the culture pond, the study suggested a dose of 2.5 mg L^?1 of CRP (0.225 mg L^?1 rotenone) for pond application.     

Genetic basis of pod borer (Helicoverpa armigera) resistance and grain yield in desi and Kabuli Chickpea (Cicer arietinum L.) under unprotected conditions

A series of half-diallel crosses involving early, medium and late maturity desi and kabuli type chickpea (Cicer arietinum L.) genotypes with stable resistance to Helicoverpa pod borer, along with the parents, were evaluated at two locations in India to understand the inheritance of pod borer resistance and grain yield. Inheritance of resistance to pod borer and grain yield was different in desi and kabuli types. In desi type chickpea, the additive component of genetic variance was important in early maturity and dominance component was predominant in medium maturity group, while in the late maturity group, additive as well as dominance components were equally important in the inheritance of pod borer resistance. Both dominant and recessive genes conferring pod borer resistance seemed equally frequent in the desi type parental lines of medium maturity group. However, dominant genes were in overall excess in the parents of early and late maturity groups. In the kabuli medium maturity group, parents appeared to be genetically similar, possibly due to dispersion of genes conferring pod borer resistance and susceptibility, while their F₁s were significantly different for pod borer damage. The association of genes conferring pod borer resistance and susceptibility in the parents could be attributed to the similarity of parents as well as their F₁s for pod borer damage in kabuli early and late maturity groups. Grain yield was predominantly under the control of dominant gene action irrespective of the maturity groups in desi chickpea. In all the maturity groups, dominant and recessive genes were in equal frequency among the desi parental lines. Dominant genes, which tend to increase or decrease grain yield are more or less present in equal frequency in parents of the early maturity group, while in medium and late maturity groups, they were comparatively in unequal frequency in desi type. Unlike in desi chickpea, differential patterns of genetic components were observed in kabuli chickpea. While the dominant genetic component was important in early and late maturity group, additive gene action was involved in the inheritance of grain yield in medium duration group in kabuli chickpea. The dominant and recessive genes controlling grain yield are asymmetrically distributed in early and medium maturity groups in kabuli chickpea. The implications of the inheritance pattern of pod borer resistance and grain yield are discussed in the context of strategies to enhance pod borer resistance and grain yield in desi and kabuli chickpea cultivars.     

Gas chromatographic determination of electron capture sensitive volatile industrial chemical residues in foods, using AOAC pesticide multiresidue extraction and cleanup procedures

Electron capture (EC) gas chromatographic (GC) parameters have been developed for determining some of the more volatile industrial chemicals that can be determined by the AOAC multiresidue method for organochlorine and organophosphorus pesticides with modified GC operating conditions. Retention times relative to pentachlorobenzene are reported for 143 industrial chemicals, pesticides, and related compounds on OV-101 GC columns at 130 degrees C. Also reported for most of the compounds are recoveries from fortified samples carried through the AOAC extraction and cleanup procedures for fatty and/or nonfatty foods, Florisil elution characteristics, and GC relative retention times on mixed OV-101 + OV-210 columns at 130 degrees C. Our laboratory has used the modified EC/GC parameters with the AOAC multiresidue extraction/cleanup procedures to determine many volatile halogenated industrial chemical contaminants in foods, chiefly in samples of fresh-water fish. Other modifications of the AOAC method are described to improve the tentative identification and quantitative measurement of these volatile residues.