JaLCDOI 10.18926/fest/11446
フルテキストURL 012_091_098.pdf
著者 Akhtar M. Shahbaz| 沖 陽子| 足立 忠司| Khan Md. H. R.|
抄録 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.
キーワード Brassica Coheritability Genetic advance Genetic variability P-starvation Selection intensity
出版物タイトル 岡山大学環境理工学部研究報告
発行日 2007-03-15
12巻
1号
開始ページ 91
終了ページ 98
ISSN 1341-9099
言語 English
論文のバージョン publisher
NAID 120002313657
JaLCDOI 10.18926/fest/11454
フルテキストURL 012_107_117.pdf
著者 Akhtar M. Shahbaz| 沖 陽子| 足立 忠司| Khan Md. H. R.|
抄録 Acclimation to orthophosphate (Pi) deprivation via highly coordinated Pi-starvation induced (PSI) classical mechanisms such as copious quantities of H(+) and carboxylates (OAs) exudation, remodeling and modification of root architecture by increasing structural and functional plasticity, enhanced uptake rate and increased synthesis of Pi transporters would reduce or eliminate our current overreliance on expensive, polluting, and nonrenewable Pi-fertilizers. These complicated but elegant morphological, physiological, biochemical and molecular adjustments of Pi-starved plants provide an excellent example of how the unique flexibility of plant metabolism and energy transduction helps them to cope in a typically stressful environment. Pi-starved roots possess enhanced H(+)-ATPase and PEPCase which could result in increasing H(+) efflux and OAs exudations in the root vicinity. This would lead to the rhizosphere acidification, which thereby contribute to the solublization and assimilation of mineral Pi from environment. To visualize the dissolution of sparingly soluble Ca-phosphate and rhizospheric pH changes (in situ), genetically diverse Brassica cultivars were grown on agar media. Newly formed Ca-phosphate was suspended in agar containing other essential nutriens. With NH(4)(+) applied as the N source, the precipitate dissolved in the root vicinity and this was ascribed to acidification. No dissolution was occurred with No(3)(-)-nutrition. In order to observe the pH changes at the media-root interface (rhizosphere), an image analysis was carried out after embedding the roots in agar containing bromocresol purple as pH indicator. Efficient cultivar 'Brown Raya' showed greater decrease in pH than P-inefficient 'B.S.A' in the culture media. Hydroponically grown cultivars were compared with respect to P-utilization efficiency (PUE), P-stress factor (PSF), and Ca- and P-uptake at P-starvation. PUE, and Ca- and P-uptake correlated significantly (P<0.01) with biomass accumulation, indicating that higher P-uptake of efficient cultivars was because of their higher Ca-uptake, which in turn was related to their better P-acquisition and PUE. Remodelling of root architecture of efficient cultivars helped the cultivars to establish a better rooting system, which provided basis for tolerance under P-starvation.
キーワード Brassica Bromocresol purple H(+) -efflux Rhizospheirc pH changes and acidification PUE
出版物タイトル 岡山大学環境理工学部研究報告
発行日 2007-03-15
12巻
1号
開始ページ 107
終了ページ 117
ISSN 1341-9099
言語 English
論文のバージョン publisher
NAID 120002313432