Tomatoes are usually consumed daily in the human diet. High temperatures reduce the number of tomato yields per year. Heat stress has been considered one of the most prominent causes of alterations in morphological and molecular characteristics in crops that decrease normal growth, production, and yield in diverse plants, including tomatoes (Solanum lycopersicum L.). In this study, we evaluated six tomato lines, namely G1, G2, G3, G4, G5, and G6, at morphological, molecular, and cytological levels under heat stress. The average results of two seasons (2018 and 2019) clarified that the G6, G1, and G2 lines recorded the highest flowering values, as well as some fruit and vegetative growth traits. Furthermore, G6 and G2 had the maximum number of fruits/plant, whereas G2 and G1 produced the highest yield/plant under high temperatures. The number of chromosomes in all lines was 2n = 24, except for G5, in which the number was 2n = 26, whereas chromosome sizes were small, ranging from 323.08 to 464.48 µm. The G1 cultivar was a symmetrical cultivar (primitive), having the highest total form percentage (TF%) and symmetry index (Syi) values and the minimum karyotype asymmetry index (ASK) value, whereas G4 was asymmetrical (advanced). Molecular marker analysis demonstrated that intersimple sequence repeat (ISSR) primers 49A, HB-14, 49A, 49B, and 89B presented the highest values for polymorphism percentage P%, marker index (MI), effective multiplex ratio (EMR), and polymorphism information content (PIC), respectively. In contrast, OP-A3, OP-B3, SCoT 2, and SCoT 12 primers showed the highest PIC, EMR, MI, P%, and resolving power (Rp) values across the studied random amplified polymorphic DNA (RAPD) and start codon-targeted (SCoT) primers. Moreover, ISSR revealed the highest number of unique specific markers (6), followed by RAPD (4) and SCoT (3) markers. Cluster analysis of combined cytological data and data relating to molecular marker attributes separated the G1, G2, and G3 lines into one group, whereas the other lines were clustered in another group. On the whole, the application of combined analysis using morphological, cytological, and molecular genetics techniques could be considered to provide suitable parameters for studying the evolution of the genetic divergence between the studied tomato lines.

The present investigation aimed to assess twenty genotypes of eggplant under open field conditions of El-Arish region during two seasons (2016 and 2017) at the Experimental Farm, Faculty of Environmental Agricultural Sciences, Arish University. The evaluation was conducted using a randomized complete block design in three replications. Results of mean performance showed highly significant differences among genotypes for all traits, the best lines were Jor-2 for early flowering, PIG-4 for both early and total yield (kg/plant) and Spa-3 for average fruit weight (g). Estimation of phenotypic coefficient of variation (PCV) was higher than genotypic coefficient of variation (GCV) for all traits. However, close estimates of GCV and PCV indicated that genetic variance contributed with large portion in phenotypic expression of most characters. Therefore, phenotypic selection is effective and suitable for improvement. The genotypic (GCV) and phenotypic (PCV) coefficients of variation were moderate for plant height, early yield/plant, total yield and fruit firmness. On the other hand, estimations were high for number of branches/plant, average fruit weight, fruit length, fruit diameter and TSS (%), indicating sufficient genetic variability for these traits and so, genetic improvement through selection is effective. Heritability estimates in broad sense were high for early yield/plant, total yield /plant, average fruit weight, fruit length, fruit diameter and TSS (%). High heritability accompanied with high GAM were found for early yield/plant, total yield/plant, average fruit weight, fruit length, fruit diameter and TSS (%) , suggesting preponderance of additive gene action and improvement through selection is effective. The genetic divergence based on Euclidean distance among twenty genotypes were grouped into five divergent clusters. The pattern of distribution showed that cluster 5 involved the largest number (nine lines), followed by cluster 1 (consisted of six lines) and cluster 4 (included three lines). While, both clusters 2 and 3 involved one genotype. Cluster means showed that first cluster gave high performance for only fruit firmness, second cluster recorded the highest mean values for total yield /plant, fruit length and TSS (%). also, third cluster produced the highest mean value for plant height, early yield/plant, average fruit weight and fruit diameter. However, fourth cluster exhibited maximum values for number of branches/plant and early flowering. So, more emphasis should be given on clusters 1, 2, 3 and 4 for choosing parents for crossing which may produce new recombinants with desired economic traits.

The present study was conducted at the Experimental Farm, Fac., Environ. Agric., Sci., Arish Univ., during successive summer seasons of 2018 and 2019, to screening twenty one genotypes of tomato as well as Galaxy 040 F1 as check to high temperature under North Sinai conditions. The analyses of variance for all studied traits revealed that mean squared of genotypes were highly significant under high average day/night-time temperature (34.6 oC and 23.9 oC, respectively) of two seasons. The studied lines CLN 1621F, Rio Grande and CLN2514A were the best for floral traits. However, the superior genotypes for fruit set percentage were CLN2026D and Rio Grande. Results of screening revealed that CLN2514A was the best for no. fruits/plant, CLN2413D and CLN1466EA for average fruit weight and CLN1621F for fruit yield /plant (2.84 kg). The highest content of proline recorded by CLN1621F and CLN3125L. Tomato genotypes ranked based on cumulative score to tolerant, moderately tolerant, moderately sensitive and sensitive groups. The clustering pattern of tomato entries grouped into five clusters. The clusters 1, 3 and 4 consisted of three genotypes, whereas the clusters 2 and 5 involved nine and four ones, respectively. Principal component analysis revealed that first two components participating 81.3% of total variability. The highest contribution towards total variability in PC1 and PC2 reflected by no. pollen grains/anther, pollen viability%, branches/plant, fruit set%, fruit yield/plant, average fruit weight, no. seeds/fruit and proline content traits, suggesting that these traits might be taken in concern for successful selection of tomato genotypes under high temperature.

Six diverse lines of tomato were crossed with six testers in line x tester mating fashion to study some plant and fruit characteristics. The experiment was conducted at the Exp. Farm, Fac. of Environ. Agric. Sci., El Arish, Suez Canal Univ., Egypt, during the period from 2012 to 2014. The test of significance and performance revealed that the genotypes, parents and crosses mean squares were highly significant for all studied traits, except number of branches/ plant. The overall mean of F1's surpassed their parents in all traits, except fruit firmnessandtotal soluble solids percentage (T.S.S.%). The mean of F1's exceeded the check hybrid in some traits; viz., plant height, number of branches per plant, total number of fruits/plant, yield/plant and total soluble solids percentage (T.S.S.%). In the remaining traits the overall mean of F1's was lower than that of parents and the check hybrid. However, this did not imply the absence of superior hybrids than mid-parents or the check hybrid. Heritability estimates in broad sense were high for all traits, except it was low for total yield/plant, Heritability in narrow sense was low for all studied traits. The percentage of G.C.V/P.C.V. was high for all studied characters, except it was moderate for total yield/plant.Significant or highly significant positive correlations were found between: Plant height with number of branches per plant and vitamin C content. Also, total number of fruits/plant with yield/plant. yield/plant with average fruit weight and Fruit firmness. Significant or highly significant negative correlations were found between: total number of fruits/plant with average fruit weight and fruit firmness.

This study was carried out on cantaloupe plants (cv ‘Gal152’ (during the winter seasons of 2019-2020 and 2020-2021 to study the effect of three soil applications of K2SO4 rates (100%, 75%, and 50%of recommended potassium requirements) and spraying four foliar potassium sources (potassium silicate, potassium citrate, potassium acetate, potassium thiosulphate, and tap water spray as control treatment). Transplanting was done on 25th December under low plastic tunnels in sandy soil The soil 100% K + foliar potassium silicate recorded the highest cantaloupe vegetative growth traits. The highest plant fresh weight was recorded by the interaction treatment of soil application at 50% of recommended K + foliar k-Acetate in the first season, while the highest values in the second season were recorded with soil 100% K +foliar K citrate without significant differences than 50% of recommended K + foliar k-Acetate. The highest plant dry weight was recorded by applying soil 75% recommended K + foliar application of K-silicate and 100 of soil K + foliar K silicate in the first season and soil 50% of recommended K + foliar K acetate without significant differences than soil application of 75% recommended K + foliar K silicate in the second season. The highest leaf pigments were recorded by the interaction of soil 100% of recommended potassium + foliar citrate potassium application in all studied traits, except chlorophyll a at 75 days after transplanting and carotenoids content at 50 and 75 days after transplanting.

Six parental lines of indeterminate tomato were used in half diallel model to study performance, degree of heterosis and combining ability.This study was conducted at the Experimental Farm, Faculty of Environmental Agriculture Sciences, Arish University during two successive seasons of 2018/2019 and 2019/2020. Results revealed that the parental lines IRS-43-2, VR-6 and VL-5-4 exhibited the best values for most studied characters,however the cross combinations IRS-43-2 x VR-6, IR-44-2 x VR-6 and VR-6 x VL-5-4 were the best among the crosses.Hybrid vigour was observed in many traits, the significant positive heterosis over the check hybrid was detected in all characters and the highest values were reflected by the crosses VR-6 x VL-5-4 for growth traits and IRS-43-2 x VR-6 for early yield, total yield and Vit. C content. Variances of combining ability and genetic components revealed that additive gene action played the main role in the inheritance of fruit set percentage, total yield plant-1, average fruit weight, fruit shape and Vit. C. Based on GCA effects, the good combiner was Vl-5-4, for growth traits; IRS-43-2 and VR-6 for early yield, total yield, number of locules, and Vit. C. The highly significant positive values of SCA effects observed in crosses VR-6 x VL-5-4 for growth traits and Vit. C; IRS-43-2 x VL-5-4 for early yield; and IR-44-1 x VL-7-4 for total yield and average fruit weight. Three promising crosses (IRS-43-2 x VR-6; IR-44-2 x VR-6; VR-6 x VL-5-4) could be used commercially as local hybrids after testing in multi locations and seasons.