الفهرس 
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Abstract
Chamomile (Matricaria recutita L.) is one of the most important medicinal plants in cosmetics and sanitary industries, with various applications. The present study aimed to the induction of mutations for mechanical harvesting in up to three harvest stages only of blossom product yield instead four stages, high flowers productivity and high oil content and quality. Three German chamomile ecotypes (Fayum, Benysuef and Menia) were used in the present study at the Experimental Research Farm of Faculty of Agriculture, Department of Genetics, Zagazig University, Egypt. The seeds of the three ecotypes were exposed to gamma rays as a physical mutagen at doses of (100, 200, 300, 400 Gray), and sodium azide as a chemical mutagen at concentrations (0.001, 0.002, 0.003 moll) at PH3. The estimated morphological and quantitative characters i.e. flowers fresh and dry weight, number of flowers, plant height, stem diameter, number of branches and days to flowering, in addition to cut efficiency, oil percent and oil composition. The results revealed that gamma rays were more efficient in mutations induction with a frequency of (74) mutants than sodium azide (50) mutants. The two Mutagens produced a wide range of qualitative and morphological changes in shape and size especially of flowers. Quantitative variation of flower yield and its component traits occurred in significant measures. Mutagens changed the mean values for different agronomical traits in both positive and negative directions. The mutants introduced in M2 generation included descriptive and quantitative changes. The mutants type classified into a dwarf, semi- dwarf, tall, early and late flowering, high number of branches, large stem diameter and high number of flowers. All mutation treatments in the M2 generation revealed a significant increase in the flower yield compared to untreated plants, except for dwarf and semi dwarf mutants. At M3 generation 18 mutants were grown as M3 families. The results confirmed the stability of these mutants. We selected five promising mutants for M4 generation. Two promising mutants were chosen which gave high stability in most studied traits, as well as, the high percent of cut efficiency (about 95% for flower number) and a homogenous flower horizon that is suitable for mechanical harvesting. The two mutants are late flowering elite mutant (F/LF5-2-1) possess the highest oil content (1.77%) and number of flowers 1595 flower , the other promising mutant (B/HNOF 8-4-2) has high oil content and chamazulene percentage (1.29%) and (13.98%), respectively. These results confirm the possibility of using these two promising mutants as new Egyptian varieties to be introduced to the Egyptian commercial cultivation.