Improving the productivity of cucumber (Cucumis sativus L.) plants subjected to combined salinity and heat stresses is a significant challenge, particularly in arid and semi-arid regions. Gianco F1 cucumbers were grafted onto five cucurbit rootstocks and, together with an ungrafted control, were grown in Egypt in a net house with saline soil during the summer season over two years. The vegetative growth, yield, quality, biochemical, and mineral composition traits were measured. Although many differences were observed among treatments, in general, the grafted plants had a performance better than or similar to that of the ungrafted plants, based on the different parameters measured. In particular, the cucumber plants grafted onto the Cucurbita maxima × C. moschata interspecific hybrid rootstocks VSS-61 F1 and Ferro had the highest early and total marketable yields. These two rootstocks consistently conferred higher vigor to the scion, which had lower flower abortion rates and higher chlorophyll contents. The fruit quality and N, P, and K composition in the leaves suffered few relevant changes as compared with the control. However, the leaves of the VSS-61 F1 had higher catalase activity, as well as proline and Se contents, while those of Ferro had higher Si content. This study reveals that the grafting of cucumber plants onto suitable rootstocks may mitigate the adverse effects caused by the combination of saline soil and heat stresses. This represents a significant improvement for cucumber cultivation in saline soil under high-temperature stress conditions in arid regions.

Bacterial wilt caused by Ralstonia solanacerum is one of the most economically and destructive eggplant diseases in many tropical and subtropical areas of the world. The objectives of this study were to develop interspecific hybrids, as potential rootstocks, between the eggplant (Solanum melongena) bacterial wilt resistant line EG203 and four wild accessions (S. incanum UPV1, S. insanum UPV2, S.anguivi UPV3, and S. sisymbriifolium UPV4), and to evaluate interspecific hybrids along with parents for resistance to bacterial wilt strains Pss97 and Pss2016. EG203 was crossed successfully with wild accessions UPV2 and UPV3 and produced viable seeds that germinated when wild accessions were used as a maternal parent in the crosses. In addition, viable interspecific hybrids between EG203 and UPV1 were obtained in both directions of the hybridization, although embryo rescue had to be used. Hybridity was confirmed in the four developed interspecific hybrid combinations with three SSR markers. EG203 was resistant to both strains Pss97 and Pss2016, while UPV1 and UPV3 were, respectively, resistant and moderately resistant to Pss2016. The four interspecific hybrids with UPV2, UPV3, and UPV1 were susceptible to both bacterial wilt strains, indicating that the resistance of EG203, UPV1, and UPV3 behaves as recessive in interspecific crosses. However, given the vigor of interspecific hybrids between eggplant and the three cultivated wild species, these hybrids may be of interest as rootstocks. However, the development of interspecific hybrid rootstocks resistant to bacterial wilt will probably require the identification of new sources of dominant resistance to this pathogen in the eggplant wild relatives.

Fusarium wilt is a serious disease of cucurbit crops including cultivated Luffa species (Luffa aegyptiaca, Luffa acutangula) causing considerable amount of reduction in yield and quality. Luffa is starting to be used as rootstocks for major commercial cucurbit crops, but little is known of its resistance against soilborne diseases. Here, 63 Luffa accessions from the World Vegetable Center genebank were evaluated for resistance to an aggressive isolate of Fusarium oxysporum f. FoCu-1 (Fsp-66). According to visual screening based on disease severity rating, 14 accessions exhibited a high level of resistance against Fsp-66. These accessions were further evaluated for resistance against Fsp-66 and two more isolates FoCu-1 (isolated from infected cucumber plants) and FoM-6 (isolated from infected bitter gourd plants). Of the 14 accessions, 11 were confirmed resistant against isolate Fsp-66. In addition, 13 accessions showed high resistance against isolates FoCu-1 and FoM-6. This is the first report of Fusarium wilt resistance in Luffa and these sources will be valuable for the development of Luffa rootstocks/cultivars resistant to soil-borne pathogen to manage this serious disease.

Cowpea [Vigna unguiculata (L.) Walp.] is a major legume crop and an important source of protein in Africa. The Kafr El-Sheikh University has a long history of cowpea breeding and improvement in Egypt. Two superior lines with high seed yield and quality were selected through mutation breeding and released to farmers as new varieties under the names Kafr El Sheikh-1 and Kaha-1. Crosses were made between these two varieties to further improve cowpea to meet farmers’ demand. Using the pedigree selection method, 13 new superior F₁₀ lines were selected and evaluated over 2 years for seed yield and related traits, earliness, and protein content under low (16 plants/m²) and high (24 plants/m²) plant densities. The results showed that plants grown in narrower space produced significantly higher seed yield per unit area than the plants grown in wider space. All developed lines produced significantly higher seed yield than the two parental lines in the 2018 trial and Kaha-1 in the 2019 trial. Line number 6 proved to be the best genotype for earliness (73.5–73.9 days after sowing), seed yield (573–647 g/m²), and crude protein content (22.7–24.3%) in both trials. In addition, line 4 with bushy determinate growth habit and high seed quality was recently released as a new variety (Sakha-1). Several other cowpea lines have clear potential for release as new high-yielding varieties with early maturity and high seed quality for farmers in Egypt. Seeds of selected lines are available from Kafrelsheikh University. This shows that mutation breeding and pedigree selection methods are among the most promising breeding methods for cowpea improvement.

Grafting can be a useful technology to improve productivity of vegetable crops, including tomato, particularly under the serious challenges of climate change for agricultural systems. This study aimed to evaluate the impact of some local tomato interspecific hybrid rootstocks along with Maxifort on the vegetative growth, productivity, and fruit quality of tomato under field production conditions. Heat-tolerant tomato hybrid 023 F ₁ was used as a scion over the two late summer seasons of 2021 and 2022. Grafting 023 F ₁ onto Maxifort or KFS-16 rootstocks resulted in the maximum plant growth. Similarly, Maxifort and KFS-16 rootstocks significantly increased the fruit setting percentage from 22.2% to 23.5% and 17.8% to 24.6%, total fruit yield from 33.5% to 53.7% and 29.6% to 51.6%, and marketable yields from 34.1% to 56.0% and 27.3% to 56.7%, respectively, during both seasons compared with nongrafted plants. These two rootstocks enhanced nutrient (nitrogen, phosphorus, potassium) uptake compared with nongrafted planted. However, grafting with the interspecific hybrid rootstocks (KFS-8 and KWS-9) significantly decreased the content of catalase, peroxidase, and proline, which might be associated with lower plant vigor and yield in these rootstocks. All rootstocks had an impact on fruit chemical composition; however, generally, Maxifort and KFS-16 had greater contents of vitamin C, β-carotene, and total antioxidants than nongrafted plants. KFS-16 had also greater lycopene content than nongrafted plants. These results demonstrate the potential use of Maxifort and local rootstock KFS-16 to boost the growth and yield of tomato plants under high-temperature stress in the late summer season.

Bacterial wilt (BW), caused by soil-borne bacteria of the Ralstonia solanacearum species complex (RSSC), is a serious disease affecting eggplant (Solanum melongena) in tropical and subtropical regions. Resistance to BW in eggplant has been identified in several accessions and wild relatives, but no source has shown broad and stable resistance across diverse strains and environmental conditions. In the first screening trial, six eggplant genotypes, including five previously identified as resistant to RSSC, were evaluated along with two tomato checks against eight BW strains representing two phylotypes (I and II) and three biovars (2, 3, and 4). In the second screening trial, 26 hybrids developed from seven parental eggplant genotypes (including the six evaluated genotypes in the first screening plus an additional one) were evaluated, together with the parents, against three BW strains (Pss97, Pss2016, and Pss4). The results showed that the parental line EG048 was highly susceptible, whereas EG44 was resistant to the three strains, with a disease index (DI) of ≤20%. Furthermore, fourteen hybrids were classified as resistant or moderately resistant to the three strains. Among them, hybrid EG27 was categorized as highly resistant to all three strains with a disease index of 5.6–7.3%. In addition, three hybrids (EG8, EG20, and EG29) were highly resistant or resistant to all three strains, with a disease index of 3.8–15.8%. A strong positive correlation was observed between wilting percentage and disease index in the eggplant hybrids across the tested strains. Our results provide valuable support for eggplant breeding programs aimed at developing hybrid rootstocks with broader and potentially broad-spectrum resistance to RSSC in tomato and eggplant.