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排序方式: 共有173条查询结果,搜索用时 31 毫秒
1.
In the past five decades, constant research has been directed towards yield improvement in pigeonpea resulting in the deployment of several commercially acceptable cultivars in India. Though, the genesis of hybrid technology, the biggest breakthrough, enigma of stagnant productivity still remains unsolved. To sort this productivity disparity, genomic research along with conventional breeding was successfully initiated at ICRISAT. It endowed ample genomic resource providing insight in the pigeonpea genome combating production constraints in a precise and speedy manner. The availability of the draft genome sequence with a large‐scale marker resource, oriented the research towards trait mapping for flowering time, determinacy, fertility restoration, yield attributing traits and photo‐insensitivity. Defined core and mini‐core collection, still eased the pigeonpea breeding being accessible for existing genetic diversity and developing stress resistance. Modern genomic tools like next‐generation sequencing, genome‐wide selection helping in the appraisal of selection efficiency is leading towards next‐generation breeding, an awaited milestone in pigeonpea genetic enhancement. This paper emphasizes the ongoing genetic improvement in pigeonpea with an amalgam of conventional breeding as well as genomic research.  相似文献   
2.
Dwarf Lulu cattle, the only Bos Taurus type of cattle in Nepal, are raised under severe environments in the mountainous zone of that country. In the present study, the body measurement traits, cytogenetic and molecular genetic characteristics of the Lulu cattle are investigated. Blood samples were collected from 31 animals in four villages (altitudes 2590–3550 m) in the southern part of Mustang. The Lulu cattle had a normal karyotype with 2n = 60, XY or XX. Only one male examined had a large submetacentric X‐chromosome and a small submetacentric taurine type Y‐chromosome. The mitochodrial DNA (mtDNA) genotypes were analyzed by PCR mediated restriction fragment length polymorphisms, displacement (D)‐loop region PCR mediated single strand conformation polymorphisms, and D‐loop region sequences. Many base substitutions were found in the D‐loop region, suggesting that the Lulu cattle originated from at least 10 maternal lines. Three types of mtDNA from these cattle were found, the Bos taurus type (n = 23), the Bos indicus type (n = 6), and the Bos grunniens type (n = 2). In the village at the lowest altitude, four of the five cows were of the Bos indicus type. These results indicated that mtDNA types of the Lulu cattle mostly belong to Bos taurus, but have been hybridized with Bos indicus cattle in lower‐elevation regions in their maternal lineage.  相似文献   
3.
We screened serum samples of 1024 goats slaughtered for chevon in Bareilly in Northern India for Salmonella antibodies with indirect ELISA, MAT-H (microagglutination test using flagellar antigens e, n, x and 1, 5) and MAT-O (microagglutination test using somatic antigens 4, 12 and 3, 10, 15). Salmonella antibodies were detected in 48, 8 and 40%, goats using Salmonella-cytotoxi-I ELISA, MAT 'H' and MAT 'O', respectively. After adjusting for test accuracy, the seroprevalence were highest for Salmonella-cytotoxi-I ELISA (46%) followed by agglutinins against 'O' 3, 10, 15 (15%) and negligible for other agglutinins. With all 5 tests, prevalence of Salmonella antibodies was significantly higher in females than in males. No significant difference was evident in prevalence of Salmonella antibodies to different antigens in different age groups of male goats except for e, n, x agglutinins that were significantly more prevalent in young adult (<6-18 months) males than in adult (>18 months of age) or young (< or =6 months of age) goats. On the other hand, in females, prevalence of Salmonella-cytotoxin-I antibodies and e, n, x agglutinins differed significantly among three age groups, being the most prevalent in adult goats. As expected, the results of different tests had little or no correlation because the different tests targeted antibodies to different antigens.  相似文献   
4.
The aim of the present study was to evaluate the expression and localization of lymphangiogenic factors (VEGF-C and VEGF-D), their receptor (VEGFR3) and lymphatic endothelial marker (LYVE1) in buffalo placenta during early pregnancy [EP], and to investigate the functional role of lymphangiogenic growth factors in placental lymphangiogenesis. The mRNA and protein expression of VEGF-C, VEGF-D, their receptor VEGFR3 and LYVE1 showed significant expression in EP1 (29–42 days) and EP2 stages (51–82 days) both in caruncle (maternal part) and cotyledon (foetal part) of the buffalo placenta. Immunoreactivity of VEGF-C, VEGF-D and LYVE1 was observed around the endometrial gland, in lymphatics and trophoblast cells, whereas VEGFR3 mainly localized in lymphatics of the caruncle and cotyledons. Cultured trophoblast cells were treated with VEGF-C/VEGF-D (50, 100 and 150 ng/ml) and combined doses of VEGF-C and VEGF-D (150 ng/ml) each for different time durations (24, 48 and 72 h). The mRNA expression of LYVE1 and PCNA was significantly (p < .001) upregulated with VEGF-C and VEGF-D and combined treatment (@150 ng/ml), as well as significantly downregulating Caspase-3 at 48 and 72 h. Thus, the present study provides evidence that lymphangiogenic factors are expressed in buffalo placental compartments and they may play a significant role in the regulation of placental function in water buffaloes.  相似文献   
5.
Persistence and binding capacity of [14C]p, p′-DDT and [14C]y-HCH were studied for one year in a sandy loam soil of Delhi, India, after surface treatment during monsoon, winter and summer seasons under field conditions. Both DDT and HCH dissipated more rapidly under the Indian subtropical climate than reported for temperate regions. In all three seasons, both insecticides dissipated most rapidly during the initial 60 days. However, in the final six months there was very little change in the residue levels. After one year, the final soil burden of DDT varied from 33 to 36% and of HCH from 14 to 15% of the initial concentrations in the different experiments. HCH bound more with the soil as, out of the total residues present after one year, more than 75% of HCH was in bound form compared with only 24% of DDT. The observed time for 50% initial dissipation of DDT ranged from 60 to 120 days, while in the case of HCH it varied from 30 to 45 days. However, the rate of loss of residues which persisted for more than 6 months was equivalent to a half-life of between 500 and 10000 days for DDT, and between 700 and 2000 days for HCH, thus illustrating the very long persistence of aged residues. Since degradation of both insecticides was apparently minimal, the data indicate that dissipation of DDT and HCH was largely due to volatilisation.  相似文献   
6.
Coniferous trees growing in the boreal and temperate zones have a clear annual cycle of photosynthetic activity. A recent study demonstrated that the seasonal variation in photosynthetic capacity of Scots pine (Pinus sylvestris L.) could be attributed mainly to the light response curve of photosynthesis. The magnitude of the light response curve varied over the season while its shape remained constant, indicating that the two physiological parameters quantifying the curve-the quantum yield per unit internal carbon dioxide concentration and the corresponding light-saturated rate-remained proportional to each other. We now show, through modeling studies, that the quantum yield (and hence the light-saturated rate) is related to the annual cycle of temperature through a delayed dynamic response. The proposed model was tested by comparing model results with intensive measurements of photosynthesis and driving variables made from April to October in three shoots of Scots pine growing near the northern timberline. Photosynthetic capacity showed considerable acclimation during the growing season. A single model describing photosynthetic capacity as a reversible, first-order delay process driven by temperature explained most of the variation in photosynthetic capacity during the year. The proposed model is simpler but no less accurate than previous models of the annual cycle of photosynthetic capacity.  相似文献   
7.
Timing of bud burst and frost damage risk for leaves of Betula spp. in response to climatic warming in Finland was examined with two models. In the first model, ontogenetic development in spring was triggered by an accumulation of chilling temperatures. The second model assumed an additional signal from the light climate. The two models gave radically different estimates of frost damage risk in response to climate warming. The chilling-triggered model forecast a significant and increasing risk with increased warming, whereas the light-climate-triggered model predicted little or no risk. The chilling-triggered model is widely applied in phenological research; however, there is increasing experimental evidence that light conditions play a role in the timing of spring phenology. Although it is not clear if the light response mechanisms are appropriately represented in our model, the results imply that reliance on a light signal for spring development would afford a degree of protection against possible frost damage under climate warming that would not be present if chilling were the sole determinant. Further experimental tests are required to ascertain the light-related mechanisms controlling phenological timing, so that credible model extrapolations can be undertaken.  相似文献   
8.
Seed protein concentration of commercial soybean cultivars calculated on a dry weight basis ranges from approximately 37 to 42% depending on genotype and location. A concerted research effort is ongoing to further increase protein concentration. Several soybean plant introductions (PI) are known to contain greater than 50% protein. These PIs are exploited by breeders to incorporate the high-protein trait into commercial North American cultivars. Currently, limited information is available on the biochemical and genetic mechanisms that regulate high-proteins. In this study, we have carried out proteomic and molecular analysis of seed proteins of LG00-13260 and its parental high-protein lines PI 427138 and BARC-6. Sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis revealed that the high-protein lines accumulated increased amounts of beta-conglycinin and glycinins, when compared with Williams 82. High-resolution two-dimensional electrophoresis utilizing pH 4-7 and pH 6-11 ampholytes enabled improved resolution of soybean seed proteins. A total of 38 protein spots, representing the different subunits of beta-conglycinin and glycinin, were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. High-protein was correlated with an increase in the accumulation of most of the subunits representing beta-conglycinin and glycinin. Comparisons of the amino acid profiles of high-protein soybean lines revealed that the concentration of sulfur amino acids, a reflection of protein quality, was not influenced by the protein concentration. Southern blot analysis showed the presence of genotypic variation at the DNA level between PI 427138 and BARC-6 for the genes encoding group1 glycinin, beta-conglycinin, Bowman-Birk inhibitor (BBI), and the Kunitz trypsin inhibitor (KTI). LG00-13260 inherited the allelic variants of the parental line PI 427138 for glycinin, beta-conglycinin, and KTI, while BBI was inherited from the parental line BARC-6. The results of our study indicate that high-seed protein concentration is attributed to greater accumulation of specific components of beta-conglycinin and glycinin subunits presumably mediated by preferential expression of these genes during seed development.  相似文献   
9.
Biological control is usually the first choice of control and prevention method for integrated pest management (IPM) strategies and has now been widely implemented by Indonesian oil palm plantations. Entomopathogenic fungus, i.e., Metarhizium anisopliae, Cordyceps militaris and Beauveria bassiana have been demonstrated to control renowned pests of oil palm. Metarhizium has been used to control Oryctes larvae and the mortality has ranged from 91.67% to 100% in laboratory and 7.4% to 88.75% in the field. Metarhizium has been applied in combination with a termite baiting system (TBS) to control termites in the field for preventive and curative action as well. In many oil palm plantations in Indonesia, Cordyceps has been used to reduce the field moth population ofSetothosea asigna. Application of Cordyceps within the oil palm circle was able to infect S. asigna pupae up to 80%. Meanwhile, Beauveria in an effervescent formulation was demonstrated to have better efficacy on Darna trima larvae. A significant finding on the biological control of basal stem rot disease (Ganoderma) was the isolation of Trichoderma sp. and Gliocladium sp.. The efficacy was conducted with promising result and techniques on the application of Triehoderma have been developed, i.e., hole-in-hole system, surgery and a mounding method. However, as the roots developed, Trichoderma was no longer able to protect the palm from Ganoderma. In spite of that, the use of Trichoderma still prolonged the life ofoil palms by up to 2-3 years. Another fungi belonging to vesicular arbuscular mychorrhiza (VAM) has been developed to control Ganoderma. The efficacy in the nursery showed promising results and the Ganoderma incidence remained low compared to the untreated control. Large scale field trials are ongoing. Challenges on the implementation of biological control in oil palm plantations are because of application and availability of biopesticides/natural enemies. Therefore, advances in research on the formulation of biological control agents are still needed.  相似文献   
10.
Soybean (Glycine max [L.] Merr.) protein and oil qualities, with respect to monogastric nutrition, have been linked to the relative abundance of specific protein subunits and fatty acids, respectively. An analysis of field-grown soybean seeds by near-infrared spectroscopy revealed significant differences in their protein and oil contents as a function of nodal position. Seed proteins from the plant apex were high in protein and low in oil content, while those from the basal region exhibited an opposite pattern of accumulation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of total seed proteins revealed that the beta-subunit of beta-conglycinin content was 4-fold higher in seeds from the apical nodes than in seeds from basal nodes. The glycinin A3 polypeptide content gradually increased in successively lower nodes from the top of the plant. Its accumulation was drastically reduced when nitrogen was applied at specific growth stages. Exogenous nitrogen did not alter the pattern of beta-subunit accumulation, but accrual of the acidic and basic polypeptides of glycinin was diminished. The remaining seed storage protein components were not influenced by nodal position or nitrogen application. Gas chromatographic analysis of fatty acids indicated that only oleic (18:0) and linoleic (18:2) acids showed variability in accumulation at different nodes. Neither the abundance nor the distribution of the fatty acids was altered by nitrogen application.  相似文献   
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