Two field experiments were conducted at Private Farm Al-Doaa region, Baltim, Kafr Ash Shaykh, Egypt in 2015, 2016 seasons to study the effect of some osmo-regulators and/or antioxidants to ameliorate the harmful effects of salinity stress on Top Star hybrid sweet pepper (Capsicum annuum, L) plants in sandy soil under drip irrigation system, during the early summer season on vegetative growth, fruit yield and quality.The obtained results could be summarized as follows:Soil application of Kitasal (2 ml/l) gave the longest plant, heaviest fresh and dry weight, largest leaf area, and gave the highest fruit yield (ton/fed.) compared with other treatments in both seasons. All foliar applications significantly increased all studied parameters compared with the untreated plants. The superior application was 250 ppm glycine-betaine followed by Glutathione (50 ppm) or Potassium silicate (250 ppm) in both seasons, respectively. Interaction between soil application of Kitasal (2 ml/l) and foliar application of glycine-betaine (250 ppm) gave the highest values of vegetative growth represented by plant height, leaf area fresh and dry weight along with, fruit yield and its component represented by fruit weight, yield/plant, and total yield/fed. From the obtained results it could be concluded that, using Kitasal (2ml/l) as soil application in combination with foliar application of 250 ppm glycine-betaine improved both growth and yield of sweet pepper plants under salinity condition.

Experiments were conducted during early summer seasons of 1996/97 and 1997/98 to screening for sold tolerance among different tomato genotypes, i.e. (MHX 668, MHX 4953, MHX 975, US, LX II, GR and Super Marmand) depending on some physiological and metabolical basis. The results could be summarized as follow:-All the studied genotypes were significantly varied in their morphological, physiological and metabolical behaviour under low temperature condition in open field. Genotypes arranged from the best to the worst in their dry matter, chlorophyll, total protein, soluble sugars and minerals as well as pollen grain weight and germination %, fruit setting and yield) and in reverse order dealing with I1 and I2 index of cold responses (tolerance or sensitive) as follows: MHX 668 -Lx 4 -MHX 4953 -US -Super marmand.  GR and at least MHX 975, respectively.Fruit setting % and yield were significantly and positively correlated with all the studied parameters and negatively with I1 and I2 index. It was found that MHX 668 and LX II were significantly the best genotypes in growth, fruit setting and yield under stress condition due to their superior physiological and metabolical behaviour and function during their different stages of development. Herein it could be concluded that, those must be utilized in breeding programs for producing new cold tolerant tomato cvs or to be directly cultivated in early summer seasons. The possibility of using one or more physiological or metabolical parameters in one or more development stage as a rapid and accurate technique for cold tolerance screening, i.e. I1 (Ch0/Ch1) index, I2 (EC1/EC2) index (their lower values indicated an cold tolerance case, whereas higher ones indicated cold injury case). Also, soluble sugars, total protein, minerals (N, P, K and Ca) as well as pollen grain weight and germination percentage, all in higher values associated with cold tolerance.

Four field experiments were conducted in late summer seasons of 1998 and 1999 to study different responses of some vegetable crops, i.e. tomato cv. Castel Rock (first exp.), sweet pepper cv. California Wander (second exp.), snap bean cv. Bronco (third exp.) and cowpea cv. Creem-7 (fourth exp.) grown in late summer season to induce thermotolerance responses (improvement of fruiting and yield) by using yeast preparation (Y1 & Y2) (25 ml/L & 50 ml/L), chelated micronutrients (CME) (1 ml / L), iodo-benzoic-salicylic acid (IBS) (0.2 gm/L) and royal jelly (RJ) (10 ppm) three times spraying on tomato. Also, Y1, Y2, IBS and ATP (50 ppm), three times spraying on pepper, snap bean and cowpea in other experiments.The results could be summarized as follows:-Successfully application of such new substances on different vegetable crops in critical season to induce thermotolerability and considerably increase their fruiting and yield.

Several pots and field experiments were conducted during 1997 (fall season, 1998 and 1999 (summer seasons) to study the possibility of using some safety combinations (prepared in Mansoura Research Laboratory), some microelements and biological agents in controlling downy mildew, improving growth and yield of cucumber plants,Results of pot experiments could be summarized as follows; the best treatments of the highest suppresive effect on downy mildew disease (lowest disease severity %) were TS-3 (0.02 and 0.04%), S1 (5 and 10 ml/L), MnSO4 (0.5 an d1 gm/L) those which recorded the lowest disease severity % between 1.0 and 5.4%, whereas control plants were strongly infected (their disease severity was 95.3 and 96.7% at the two seasons, respectively. Also, plant guard (bio-agent) (2, 4 ml/L) had an considerable suppresive effect.For field experiment, the selected best treatments from pots experiment were used herein. The best treatments of the lowest disease severity and the highest growth and yield parameters were: TS-3 (0.02%), which reduced the severity of disease by 82.8%, increased dry weight by 143.7% and fruit yield by 166.6% relative to the control. These values were 77.6, 111.0 and 158.3%, respectively for S1 (5 ml/L); 70.8, 93.0 and 125.0% for MnSO4 (0.5 gm/L); 40.8, 85.1 and 116.0%, respectively for plant guard (4 ml/L).The results also indicated that some safety agents (nutritive micro-and macro-elements) alone or in combinations as (MnSO4, KOH and H2SO4) could be efficiently used in safety and economic concentrations in controlling the pathogenic fungus (down mildew) paralleled with improving growth and yield of plants. Meanwhile, the results of statistical correlation between disease severity % and some characters confirming the present findings.