Field experiments were carried out in Egypt to investigate the infestation rates of cotton whitefly Bemisia tabaci on five cultivars of cucumbers Cucumis sativus during two consecutive late summer seasons from 11 August to 28 October 2015 and 2016. The susceptibilities of the cultivars to infestation by this pest were examined. The five cultivars – Hayl, Nems, Beit Alpha Zena, Bahi and Wafier – were cultivated on a private farm in Mansheyet Saqqara village, Giza. The results showed that whitefly infestation peaks were high in September and October, but low in November in both seasons. The population densities of Bemisia tabaci eggs, nymphs and adults on all the cultivars were slightly higher in 2015 than in 2016. Numbers of B. tabaci eggs, nymphs and adults rose with increasing the temperatures in both seasons, and mean numbers of nymphs and adults also increased with decreasing RH% on all the cultivars. The combination of temperature and humidity was an important regulatory factor affecting B. tabaci development. The results of this study showed that high infestation peaks of B. tabaci occurred in September and October of both seasons. The present results were used to classify the degrees of susceptibility of these cucumber cultivars to B. tabaci infestation as susceptible (S), low resistant (LR) and moderately resistant (MR). It is important that these degrees of susceptibility be referred to the degree of resistance of each cultivar to insect infestation.

T HE ECONOMIC feasibility of using the tomato yellow leaf curl virus (TYLCV) resistant F 1 tomato hybrids (Solanum lycopersicum L.) may be improved by using their F 2 generation in commercial production. Hence, this study was performed to evaluate the F 1 and F 2 generations of 15 TYLCV-resistant/tolerant commercial tomato hybrids during the 2018 and 2019 fall seasons to identify the best hybrids and F 2 populations for commercial production. Both F 1 and F 2 populations were evaluated separately for TYLCV-resistance, yield, and fruit quality traits. Broad sense heritability (H 2 b ) values of TYLCV-resistance were high, being > 60% in hybrids 186, Goldstone, Rabha, SV0922, and SV8320 in both seasons. F 1 and F 2 populations of '186', 'Dania', 'PS550', 'Rozalina', 'SV0922', 'SV8320', and 'Tyrmes' had the highest total yield (TY)/plant, low TYLCV disease (TYLCVD) mean scores, acceptable fruit quality traits, and average fruit weight > 80 g. Desirable inbreeding depression (ID) values were observed for TYLCVD-mean score in F 2 populations of most evaluated hybrids; for TY/plant in F 2 populations of 'SV3773' in both seasons, and in populations of '186', '448', 'Goldstone', 'Rabha', 'SV8320' and 'SV0922' in the second season. Most hybrids had desirable significant ID values for fruit quality traits. Accordingly, it is concluded that the F 2 populations of hybrids 186, SV0922, and SV8320 may be used in commercial tomato production under TYLCVinfection in the fall season.

This investigation was conducted in the research facilities of the Horticulture Research Institute during the period from 2003 to 2006 to produce and evaluate some tomato hybrids having ripening inhibitor mutant gene rin and study effect of this gene on some quality characters, yield and fruit shelf life. Twenty four tomato cvs. were crossed as female parents with Incridible cv. as male parent. The cultivar Incridible carries rin mutant gene. Parents and F1 populations were planted in RCBD with 4 replicates in two successive summer seasons 2005 and 2006 in open field to evaluate them. It was found that the hybrids Black From Tula  Incridible and VFNT  Incridible produced the highest significant early yield (7.7 and 6.85 ton /feddan, respectively). Nine hybrids out of them exhibited significant positive high parent heterosis for early yield ranged from 36.81 to 146.79% with the hybrid Black From Tula  Incridible having the highest value. The hybrid Strain B  Incridible produced the highest total yield (17.54 ton/fed.) over all evaluated genotypes; the hybrid Packmore B Incridible exhibited the highest positive high parent heterosis for the same trait. The cultivar Polish produced the highest significant average fruit weight over all evaluated cvs. with mean value 241.4 g. The cultivars Black From Tula, ranked second in this trait having mean value being 205.8g, the two hybrids VFNT  Incridible and Castle King  Incridible showed significant positive high parent heterosis. The cultivar Incridible significantly was the highest value among all evaluated genotypes in fruit firmness, fruit firmness during 35 days, and storage ability. All of the evaluated hybrids were not superior in fruit firmness compared to high parent where they showed significant negative high parent heterosis for these traits.

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