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31.
This study presents the molecular barcoding results of giant freshwater prawns and allied products collected from inland landing centres, markets and stores of Vembanad Lake (Kerala state, India) which is recognized as a natural abode for Macrobrachium rosenbergii. Prawns collected from landing centres of the lake could be easily identified as the above with their large size and morphological characters. There were certain ‘alien’ prawns and prawn products (headless shell on, peeled and deveined) traded in the markets and stores of this region as M. rosenbergii. Genotyping of all these samples using COI and 16S rRNA gene sequences confirmed the speciation of individuals from inland landing centres as M. rosenbergii, ‘alien’ prawns and certain prawn products as M. malcolmsonii. To ensure the same and to detect the presence of any other congeners of genus Macrobrachium inhabiting Vembanad Lake, additional homologous COI and 16S rRNA sequences available in NCBI were acquired and incorporated for molecular analyses. Results generated from NJ tree and genetic distance data confirmed the trade of non‐indigenous Macrobrachium species M. malcolmsonii in Kerala for the first time and its use as a species substituent for M. rosenbergii.  相似文献   
32.
The present study was conducted to investigate the changes in mineralization and morphology in response to graded levels of dietary phosphorus in Indian major carp, Catla (Catla catla) fingerlings (av. wt. 4.23 ± 0.87 g). The experimental system constituted of 24 150-L capacity plastic tanks (eight treatments, three replicates) stocked with 20 fingerlings each. Eight isonitrogenous and isocaloric semi-purified diets (crude protein 35%, crude lipid 8.5%) were formulated with graded levels of phosphorus (0%-control; 0.1; 0.3; 0.5; 0.7; 0.9; 1.1; 1.3; 1.5%) using KH2PO4. The fish were fed twice daily with the respective feeds for a period of 120 days. The percentage of ash content in whole body, vertebrae and opercular bones was found to be significantly (P < 0.05) lower in fish fed low levels of dietary phosphorus (T1, T2) in comparison with other treatments. The concentration of phosphorus and calcium was found to be significantly (P < 0.05) lower in whole body, vertebrae and opercula of fish fed low phosphorus diets (T1, T2) relative to treatments with higher levels of dietary phosphorus supplementation. The concentration of magnesium in opercular and vertebral tissues of T1 group was significantly (P < 0.05) lower than all other groups. The X-ray radiographs did not reveal any skeletal deformities in any of the treatments. Truss analysis showed absence of significant morphological variations between fish of different treatments. The deficiency of dietary phosphorus in catla led to significantly lower mineralization of whole body and bone tissues, but the deficiency was not severe enough to cause skeletal deformities and morphological changes in the fish.  相似文献   
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Age, growth and maturity data of the freshwater feather back Chitala chitala (Hamilton-Buchanan, 1822) were collected from ten different geographical locations. Out of ten populations, maximum 6+ ages were recorded from four river basins namely river Bhagirathi, Koshi, Saryu and Ganga and the back calculated lengths at 6+ ages ranged from 1033.36–1073.63 mm. In rest of the locations, however, only 3+ age classes were recorded. Specific rate of linear growth (Cl) and specific rate of weight increase (Cw) showed decreases except in two locations. The specific rate of linear growth (Cl) and the specific rate of weight increase (Cw) increased at 3+ age class in the river Bhagirathi. Among other growth parameters, three distinct life stages of C. chitala were observed based on analysis of growth constant data. Analysis of variance (ANOVA) of the back-calculated length data of 10 populations indicated a significant difference (p < 0.05). Out of ten populations studied, six showed significant variation of growth in 1+ age class and two showed significant variation in 2+ to 6+ age classes. Length-weight relationship of the species from all the population was calculated and the coefficient of correlation (r) was at the significant level where the value of ‘b’ was almost 3 for all the locations studied. Male C. chitala attained maturity earlier (2+ age) whereas females matured at age 3+. The percentages of mature individuals also varied between river basins. Based on this study strategies can be proposed for sustainable exploitation of the species from wild populations.  相似文献   
35.
Haploid mutagenesis offers several advantages over conventional (seed) approach. However, its potential has not been utilised for Brassica juncea, an important oilseed. In this study, mutant donor plants of three Indian B. juncea genotypes, generated by ethyl methanesulfonate (EMS) and ethyl nitrosourea (ENU), were used for microspore culture. The response of mutant donor plants was about 100 times lower than non-mutant controls; a total of 9,411 embryos were produced from the EMS treated donor plants, while microspores isolated from ENU treated donors did not yield any embryos. The lethality of induced mutations demonstrated itself mainly as the induction of abnormal embryos (80%), failure of germination (70%) and failure of plantlet development (70%). Nine doubled haploid (DH) mutant lines and three non-mutant DH lines obtained through this approach were tested for agronomic and biochemical variation over two growing seasons. High variability was observed and stable mutants were recovered for reduced height (125 vs. 168 cm for the control), appressed pod character, altered fatty acid composition higher protein proportion in de-oiled meal (48%) and a lower glucosinolate content in de-oiled meal (59.5 μM/g) relative to controls. The approach demonstrates that despite severe reduction in efficiency of the DH line production, valuable mutants can be recovered from mutated donor plants.  相似文献   
36.
Summary Divergence of 25 accessions of Brassica juncea of Indian, CIS (Commonwealth of Independent States, former USSR) and synthetic origin was studied by D2 analysis. On the basis of divergence, ten accessions were selected and crossed in a diallel fashion without reciprocals to study the combining ability and heterosis. None of the accessions was found to be a good general combiner for all the nine quantitative characters that were studied. Significant heterosis over better parent for single plant yield was recorded in CIS x Indian and synthetic x CIS crosses (5 each) followed by Indian x synthetic types (3). The analysis of component characters showed that the mean performance of the majority of hybrids was intermediate for five out of six yield attributing traits, thus exhibiting dominance or partial dominance effect. To estimate the contribution of such yield attributing traits towards heterosis for yield, a comparison was made among three parameters viz. heterosis over mid parent (MP), better parent (BP) and better yielding parent (BYP) of the concerned hybrid. It was observed that estimation of heterosis from BYP was a more accurate method to determine the contribution of component characters towards yield heterosis than the analysis based on MP and BP. From the component character analysis, it was concluded that characters like number of primary and secondary branches, number of siliqua per plant and siliqua density contributed significantly towards heterosis in yield. Plot level yield trials of two selected hybrids (Skorospieka II x RH30 and Donskaja IV x Varuna) over two growing seasons revealed 29.4 to 91.8% heterosis over BYP.  相似文献   
37.
Cajanus platycarpus, a distantly related wild species, was successfully crossed with cultivated pigeonpea using embryo rescue and tissue culture techniques. Advance generation lines showed a range of desirable characters including cytoplasmic male sterility. A range of pigeonpea cultivars restored fertility and was maintained by a few lines including cultivar ICPL 85010. Clasmogamous flowers were observed in the male sterile lines. In such flowers anthers did not form di-adlephous bundle. Cytological analysis revealed that meiosis proceeded normally till the tetrad stage in those anthers with pollen grains. After which many of the pollen grains turned sterile. In the anthers with pollen grains, dehiscence was not observed, thus creating functional sterility. In many other anthers, pollen mother cells (PMCs) were not formed at all, giving rise to sepalous anthers. In conclusion two mechanisms of male sterility existed, one was premeiotic, where PMCs did not form and in the second, although PMCs gave rise to pollen grains, they were either partially or totally sterile accompanied by non-dehiscence of anther wall.  相似文献   
38.
The Rev1 DNA polymerase is highly specialized for the incorporation of C opposite template G. We present here the crystal structure of yeast Rev1 bound to template G and incoming 2'-deoxycytidine 5'-triphosphate (dCTP), which reveals that the polymerase itself dictates the identity of the incoming nucleotide, as well as the identity of the templating base. Template G and incoming dCTP do not pair with each other. Instead, the template G is evicted from the DNA helix, and it makes optimal hydrogen bonds with a segment of Rev1. Also, unlike other DNA polymerases, incoming dCTP pairs with an arginine rather than the templating base, which ensures the incorporation of dCTP over other incoming nucleotides. This mechanism provides an elegant means for promoting proficient and error-free synthesis through N2-adducted guanines that obstruct replication.  相似文献   
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Induced breeding of climbing perch, Anabas testudineus was conducted by synthetic hormone Wova‐FH in the intensity level of 0.1, 0.2 and 0.3 mL kg?1 of body weight respectively. The brooders were injected one time and left to spawn in the spawning hapa in the sex ratio between male and female as 2:1. It was found that at all the intensity level hormone Wova‐FH could enhance the fishes to breed and lay eggs whereas no breeding was observed in control set. The spawning time, quantity of the brooder spawn, fertilization rate, hatching rate and survival rate were quantified in each set of experiment. The egg output/female was significantly higher in 0.3 mL in comparison with 0.1 and 0.2 mL kg?1 of body weight. The statistical analysis showed significant (P≤0.05) effect between hormone dose on fertilization rate, egg output and hatching rate. The present experiment suggests that Wova‐FH at the dose of 0.3 mL kg?1 body weight of fish is more effective which might be considered for raising captive population.  相似文献   
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