| JaLCDOI | 10.18926/fest/11446 |
|---|---|
| FullText URL | 012_091_098.pdf |
| Author | Akhtar M. Shahbaz| Oki, Yoko| Adachi, Tadashi| Khan Md. H. R.| |
| Abstract | The potential of a crop favorably respond to breeding/selection and bioengineering programs depends upon the nature and magnitude of genetic variability. For effective selection, information on nature and magnitude of variation in population, association of character with dry matter yield and among themselves and the extent of environmental influence on the expression of these characters are necessary. The estimates of genetic parameters help in understanding the role of various plant traits in establishing the growth behavior of cultivars under a given set of environmental conditions. Genetic analysis leads us to a clear understanding of different morphological, physiological and genetic characters and also the type and extent of their contribution to dry matter yield. Six Brassica cultivars were grown in a P-deficient sandy loam soil for 49 days after sowing. Significant variations were observed for all the characters in all the cultivars used in the experiment. All the characters showed high heritability coupled with high genetic advance. Heritability (h(2)) is an approximate measure of the expression of a character. The highest estimates of broad sense heritability (h(2)= 0.90) and relative expected genetic advance (85.72%) were noted for root dry matter (RDM), while the estimate of expected genetic advance at 10% selection intensity was quite high (ΔG = 85.30c㎡) for leaf area per plant. The estimates of coheritability were positive and relatively higher for rootshoot ratio (RSR) in combination with shoot dry matter (SDM) (coh(2) = 2.002) and phosphorus use efficiency (PUE) (coh(2) = 1.875), whereas coheritability estimates were negative between leaf area per plant and RSR (coh(2) = -0.2010) indicating lack of association between these traits. High heritability with high genetic advance was exhibited by all the studied plant traits of cultivars evidencing that the traits could be further improved through individual plant selection. The innate variations within the Brassica gene-pool impel to drive a concentrated effort to understand the basis of adaptability. Access to the relevant genetic traits and information will provide necessary tools to select the optimal combinations of alleles adapted to local and changing growing environments especially nutrient stress conditions such as phosphorus (P) starvation. |
| Keywords | Brassica Coheritability Genetic advance Genetic variability P-starvation Selection intensity |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2007-03-15 |
| Volume | volume12 |
| Issue | issue1 |
| Start Page | 91 |
| End Page | 98 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313657 |
| JaLCDOI | 10.18926/fest/11443 |
|---|---|
| FullText URL | 012_083_089.pdf |
| Author | Khan Md. H. R.| Rahman Md. K.| Rouf A. J. M. A.| Sattar G. S.| Akhtar M. S.| Oki, Yoko| Adachi, Tadashi| |
| Abstract | The pH values in the profiles of unburnt (agricultural land) soils were found to increase as a function of soil depth and burning (400 to 1000℃) of the soils increased average pH by 8%. The average sand content of the burnt (soil around brick kilns) soil profiles was increased by 245%, while 39 and 36% decreased the silt and clay contents. Soil organic carbon (Corg) in the unburnt soils (0-20 cm) at different agro-ecological zones in the eastern region of Bangladesh ranged from 0.8 and 1.4%, whereas the content of microbial biomass carbon (Cmic) in the studied unburnt soils ranged between 5 and 7% of the total Corg, suggesting that the microbial biomass releasing considerable amounts of carbon in soil while burning of the soils drastically reduced this contribution to about 1%. The values of soil Cmic in the unburnt soils were approximately 2 to 6 times higher in the topsoils than the subsoils (20-60 cm). Variable rainfall, temperature and soil fertility had an overriding influence, which was reflected by the average minimum (276 μg g(-1)) and maximum (439) amounts of soil Cmic in Moulvibazar and Cox' Bazar sites. The Cmic decreased upon soil burning by 92% of its original average value (346 μg g(-1)) in the soil profile of up to 100 cm. Burning of topsoils strikingly increased the Corg/Cmic ratio by about 6 to 9 times, while reduced the C/N ratio by about 1.5 to 2.5 times. The average loss of Corg, available and total N due to burning of the soils were 66, 72 and 44% (increase over average content of unburnt soil: IOAC), respectively, which suggests that the burning of the soils offset the essential roles of soil microorganisms, reduced soil fertility and soil microbial contribution. |
| Keywords | brick burning C/N ratio microbial biomass carbon soil organic carbon ratio of microbial biomass to organic carbon. |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2007-03-15 |
| Volume | volume12 |
| Issue | issue1 |
| Start Page | 83 |
| End Page | 89 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313396 |
| JaLCDOI | 10.18926/fest/11441 |
|---|---|
| FullText URL | 012_077_081.pdf |
| Author | Khan Md. H. R.| Mohiuddin M.| Rahman M.| Akhtar M. S.| Oki, Yoko| Adachi, Tadashi| |
| Abstract | Studies on the existing non-symbiotic diazotrophic systems still are the most promising for better use of biological nitrogen fixation (BNF) in agriculture. The possibilities for the extension of nitrogen fixation to rice plants still speculative. The prospect of extension of N(2)-fixation to other plants was originally formulated to simulate the possibilities for the biological use of atmospheric nitrogen in order to overcome the ecological and economical problems of nitrogenous fertilizers. In view of this, the present study was conducted for the characterization and identification of N(2)-fixing bacterial strains at the maturity (110 days) stage in rhizosphere of rice (BR 10, Oryza sativa L.) grown in Brahmaputra Alluvium soil of Bangladesh. The soil is characterized as 'Inceptisol' order and 'Aquept' suborder. It was identified as 'Dhamrai series', had 'silt' texture, pH 6.0 and 6.8 C/N ratio. The present results of the microbial tests on the rice rhizosphere soil demonstrated that out of 401 isolates, only 94 were branded as nitrogen fixing organisms per gram of soil, which is about 23.4% of the total isolates. Based on the selection criteria, four individual strains were selected for identification. Biochemical tests were conducted for proper identification. They were identified as Closteridium spp., Klebsiella spp., Bacillus spp. and Azospirllum spp. |
| Keywords | Azospirllum spp. Bacillus spp. BNF Closteridium spp. Diazotrophs Klebsiella spp. Oryza sativa L. |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2007-03-15 |
| Volume | volume12 |
| Issue | issue1 |
| Start Page | 77 |
| End Page | 81 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313950 |
| Author | OKi, Yoko| Utsugi, Tomo| |
|---|---|
| Published Date | 1998-02 |
| Publication Title | 岡山大学農学部学術報告 |
| Volume | volume87 |
| Issue | issue1 |
| Content Type | Departmental Bulletin Paper |
