The present research work has been carried out to study the response of three genotypes of sugarcane (Saccharum species hybrids) for callus induction, embryogenic callus production and their in vitro salt tolerance.For callus induction and embryogenic callus production, leaf base segments were subjected to in vitro culture on Murashige and Skoog (MS) medium supplemented with 3 mg l -1 2,4 Dichlorophenoxyacetic acid for 4 weeks. To evaluate salt tolerance of the varieties, cultured calli were exposed after two subsequent subcultures (4 weeks each) to different concentrations of NaCl (0, 17, 34, 68 and 102 mM) added to the culture medium for 4 weeks. Comparison of genotypes was based on callus induction percentage, embryogenic callus production percentage and relative fresh weight growth. For salt tolerance, necrosis percentage and relative fresh weight growth of callus were used. The three genotypes responded well to callus induction with about 82, 84 and 100 percentage of induction for GT 54-9(C9), NCo310 and Co 413, respectively. The high per cent of embryogenic callus obtained for the three varieties indicated that these genotypes have a high capacity for embryogenic callus production. Relative fresh weight growth of callus was about 1.076, 1.282 and 0.925 for GT 54-9, NCo310 and Co413, respectively. The effects of NaCl resulted in calli necrosis and a reduction of their growth. Growing calli derived from genotypes GT 54-9 and NCo310 showed less necrosis percentage and less relative fresh weight growth reduction under salt stress. They appeared to be more salt tolerant in vitro than Co 413.The finding of superior genotypes GT 54-9 and NCo 310 and inferior one Co 413 for salt tolerance together with their high potential for embryogenic callus induction may be a model varities to study physiological mechanisms associated with in vitro salt tolerance and in vitro selection for salt tolerance in sugarcane.

Stevia (Stevia rebaudiana Bertoni) extract has been recently introduced to Egypt as a non-nutritive sweetener. In this work we tested the possible capability of stevia extract in inducing micro as well as macro DNA lesions. The golden hamster (Mesocricetus auratus; 2n = 44); and human lymphocyte (Homo sapiens, 2n =46) genomes were employed to test the genotoxicity of the extract on a more sensitive genome as well as on the human genome directly. Various short-term genotoxic bioassays were used including analysis of chromosomal abnormalities in hamster bone marrow and human lymphocytes, in vivo induction of sister chromatid exchanges in hamster bone marrow, in vitro induction of sister chromatid exchanges in human lymphocyte culture, micronucleus test in hamster bone marrow.The study shows that the two genomes respond to the extract differently. The extract induces significant levels of chromosome abnormalities in hamster, whereas it does not induce such higher levels of abnormalities in human lymphocyte culture. Analysis of sister chromatid exchange frequencies revealed that the extract induces significant levels of primary DNA damage in hamster bone marrow compared to the human lymphocytes. This study concludes that hamster seems to be more sensitive compared to human and other experimental genetic models used in genotoxic assays. Data from this study and previous studies on other genetic models are discussed.

The aim of this investigation was protection the sugarcane breeding varieties from infestation with the pink stem borer , S. cretica Led, at El-Sabahia Station , Alexandria . G 85-37variety (95 borers/100 plants) was more susceptible to infestation with the pink stem borer in two seasons . Moreover G85-39 was the most resistance to this borer (24 borers /100 plants) in the same seasons. There were significantly among varieties value as susceptibility to infestation by S. cretica . The leaves weight of G85-37 variety was the highest recorded (1312 gm ) in weight leaves value in both seasons. On other hand, the Co214 (775gm )was the least one in same character. Stalks weight character was significantly lower among varieties in both seasons. The highest total soluble solid (T.S.S) value was appointed in 1 st season by G85-39 (20.67).While it was low by F153 (16.33)&(16.17) in both season respectively. During the season 2006/2007, the evolution of 4 insecticides and 2bioinsects were done. In the third day the Dipel 2x (B. th. krustaki ) reduced the population of S. cretica by 19.33% in first period time (three leaves stage) and 16.67% in second period (Harvest time ). While reduction % was 0.0 % by B. bassiana ( Bio fly) in both period. Lannate reduction percentage was more toxicity (91%) than Carbaryl (80.67%) in same period . In three leaves stage (1 st period test) the Profenofos was very effective at third day (92.33) . Bio-insecticides were more toxic in last priod(21day) for test at two application periods In addition, Dipel 2x ® is more toxic than (Bio fly ® ) . Organophosphours insecticides increased the sugarcane yield character than another tested insecticides. IT could be concluded that all tested insecticides could be used against S. cretica .Using chemical insecticides gave fast reduction of then Bio-insecticides which are safety and less pollution than chemical insecticides.

Response of three varieties of sweet sorghum (Sorghum bicolor) namely: Hunny, Brandies and Prawel, to callus induction, embryogenic production, and in vitro salt tolerance were studied. In addition electrophoretic patterns of proteins and peroxidase isozyme patterns were studied to evaluate the response the obtaining calli of sweet sorghum to salt treatments with different concentrations of NaCl. The results obtained showed differential effect among the tested varieties. Brandies variety showed high response for callus induction, callus weight and salt tolerance comparing with other varieties. The present results might be useful in evaluative purposes in breeding program.

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