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Structural changes of the photosynthetic apparatus; morphological and cultivation responses in different wheat genotypes under drought stress condition
| Content Provider | Semantic Scholar |
|---|---|
| Author | As, Pireivatlou Aliyev, R. T. Si, Hajieva Si, Javadova Akparov, Zeynal |
| Copyright Year | 2008 |
| Abstract | To understand genotypic responses of wheat genotypes to drought stress, this project studied 64 different wheat genotypes under both irrigated and drought stress conditions, using simple lattice experimental design with two replication in research area of agricultural research station of Ardabil and research area and laboratory of genetic resources institute of Azerbaijan during two seasons 2006 to 2007. Drought reduced wheat grain yield by 61.9% and stress intensity (SI) for wheat grain yield was 0.62. The genotypes studied were classified into three groups; tolerant, moderate tolerance and susceptible by genotypic responses of wheat genotypes under both irrigated and drought stress conditions and on the basis of values of SSI and STI indices. Results of germination capability of wheat genotypes evaluated under 16 atmosphere drought stress of PEG and control (water) treatments showed the same results as field experiments on the basis of the classifications of wheat genotypes for three classes; tolerant, moderate tolerance and susceptible. Results of changes of amounts of chlorophyll also showed significantly differences (p<0.1) between genotypes examined basis of amount of chl a, chl b, chl a+b and chl a/b under 20 atmosphere drought stress of PEG and control (water) treatments. Drought on average reduced amount of chl a, chl b and chl a+b, by 2.5, 6.6 and 2.5% respectively. However the amounts of reduction in chl a, chl b and chl a+b were different between genotypes studied, so that the amounts of chl a, chl b and chl a+b were increased in drought tolerant wheat genotypes. According to the depression degrees of chl a+b the classifications of wheat genotypes were also the same as the classifications of field experiments and germination capability under 16 atmosphere drought stress of PEG and control (water) treatments. The amount of chlorophyll was positively correlated (r =0.36**) with grain yield and with leaf area index (r =0.15ns) of wheat genotypes. Drought reduced genotypic variation and heritability of wheat genotypes in most of examined characters. However heritability of grain yield and leaf area index was increased in drought stress condition. Finally according the studied characters the genotypes No. 6, 30, 37, 42, 43 and 44 were found to be tolerant genotypes. INTRODUCTION Under Iranian climatic conditions drought stress is a permanent problem of the wheat crop, often causing yield losses. Therefore improvement of cultivars for drought resistance is one of the main aims of wheat breeding programs. Photosynthesis, which is the most significant process influencing crop production, is also inhibited by drought stress (Bradford and Hsiao 1982). Little is known, however, about other structural changes in thylakoids under water stress conditions. Water deficiency causing the closure of stomata leads to a lowered internal concentration of CO2, which in turn inhibits the Calvin-cycle, and the consequent shortage of reducible coenzymes gives photoinhibitory conditions (Horton et al. 1996). Structural parameters of chlorophyll were compared in different Triticum aestivum L. genotypes to characterize the water deficiency tolerance of their photosynthetic apparatus, and evaluate the morphological and cultivation responses of wheat genotypes. MATERIALS AND METHODS The 64 diverse wheat genotypes were studied in field experiments under both drought stress and normal conditions from 2006 to 2007 growing year. Each of experiment was laid out in a lattice design with two replications. Field experiments were planted on 15 November 2006 in a clay loam type of soil at the research area of Genetic Resources Institute of Azerbaijan National Academy of Science-Bako Republic of Azerbaijan and Agricultural and Natural Resources Research Station of Ardabil-Islamic Republic of Iran. Plants in normal condition were irrigated until they reached physiological maturity. Plants in normal condition received 672.4 mm of water (406 mm irrigation + 266.4 mm rain) and those in drought stress condition received 266.4 mm rainfall and plants in drought stress condition was not irrigated. In the growing season, the total amount of rainfall was 266.4 mm, close to the long-term average of the Ardabil region (long term average was 280 mm). However, of 266.4 mm of rainfall, 78.7 % was received before booting stage, 19.6 % received between booting and heading stage, and 1.7 % fell between heading and early grainfilling period. The absolute maximum and mean temperature in grain filling period were 27.6 C and 8.0 C, respectively. Each plot consisted of 2 rows, 2 m in length. Inter row spacing was 30 cm and interplant |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://ses.library.usyd.edu.au/bitstream/handle/2123/3388/P207.pdf;jsessionid=A3786D6C0F8EE2CD32BD19E5C9DEE8E7?sequence=1 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
