| Variation among EMS-Induced Wheat genotypes for chlorophyll
content Y.A. AL-SAHEAL Department of Agronomy and Range Science Gassim College of Agriculture, King Saud University, Saudi Arabia The artificial induction of mutations plays an important role in the study of the mechanism of heredity and evolution. Numerous experiments have contiributed to an increased knowledge of the fundamental concepts of genetics. Extensive research has also been reported on the inheritance and variation of chlorophyll contents among chlorophyll deficiency mutants for several crops including wheat (JENSEN 1957). The present study was initiated to determine the variation of chlorophyll concentration among normal and EMS-induced populations of wheat genotypes. The improvement of genotypes with high chlorophyll content might result in the improvement of photosynthesis in wheat plant leading to the improvement of grain yield. Material and Methods Homogeneous seeds of five hexaploid wheat cultivars namely; Al-Samma, Arbian, Hinta Madina, Maaya and Yocorojo were treated with different doses of Ethyle Methane Sulphonate (EMS) with different durations in Rabi 1983 (Table 1). Treated seeds along with control were sown in pots in a complete randomized design in a greenhouse of the Department of Agronomy and Range Science, Gassim College of Agriculture, king Saud University, Saudi Arabia. For Chlorophyll estimation leaf samples from second flag leaf of the main culm of all the genotypes from each treatment were collected just before flowering (80 days after sowing). Chlorophyll was extracted from 0.1 gm of freeze-dried leaf blades with 30 ml of 80% acetone. The plant extract was filtered through filter paper (Whatman No.1) and made to 50 ml final volume. Absorbance was determined Spectrophotometrically at 645 and 663 mu (Bausch and Lomb Spectronic-2000) and total chlorophyll (mg chlorophyll/g dry weight) was calculated according to the equation of ARNON (1949). The data was analysed statistically using the General Linear Models (GLM) procedures of SAS (HELWIG and COUNCIL, 1979). Duncan's Multiple Range Test was conducted to determine differences between means. Results and Discussions Visual differences for leaf color among EMS-induced M1 populations and their parents are readily apparent. From Table 1, it may be inferred that total chlorophyll content of all the M1 populations displayed general trend of increase over their parents (control) except variety Arabian where the character showed decrease at all doses and durations (except 0.4% and 0.6% at 9 and 7 hr respectively). It was further noted that there had been an absence of any linear decline. The intensity of green coloration in the foliage differed among M1 populations ranging from light green to dark green. The dark green populations were higher for total chlorophyll, chlorophyll a and chlorophyll b than the light green populations, while the medium color populations reacted in between them for chlorophyll characteristics. Sirnilar results were reported by AASE (1971), JOHNSON & OHKI (1981) and LARIK et al. (1984) in barley and wheat respectively. |
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