Fildaus Nyirahabimana

Ovary culture is among the most effective techniques for haploid induction in horticultural crops, including cucumber. The application of doubled haploid technology can significantly accelerate cultivar development by enabling the rapid production of homozygous inbred lines. This study evaluated the effects of culture medium combinations of plant growth hormones (2,4-D, NAA, IAA, IBA, PUT, BAP, KIN, TDZ) on haploid induction in cucumber via ovary culture. Four induction and five regeneration media were tested across four cucumber varieties: Beith Alpha, PTK40, Botanik, and Sardes. The highest embryo formation rate (88%) was observed in the Botanik variety, followed by Sardes, PTK40, and Beith Alpha, particularly on induction medium supplemented with 2,4-D and PUT. Plant regeneration was achieved on a medium containing IAA and BAP. Flow cytometric analysis of twenty randomly selected plants confirmed that all were diploid, with no haploids detected. This outcome indicates that the primary objective of inducing haploid plants was not successfully accomplished. These findings highlight substantial limitations in the current induction protocol and underscore the need for further optimization to improve haploid recovery efficiency. The authors recommend more research to develop and improve ploidy level stability for cucumber ovary culture.

Genotyping by sequencing (GBS) is a very helpful approach and one of the most useful techniques for examining and analysing the genetic variation of various lines and varieties. GBS technology was used to identify single nucleotide polymorphisms (SNPs) and assess genetic variation in several watermelon accessions. GBS application in watermelon breeding programs has recently become a popular technique among many breeders. Watermelon (Citrullus lanatus L.) is a warm-season crop that is widely cultivated for its delicious fruit. And it is one of the most economically significant crops in the world. However, watermelon cultivation is frequently hampered by abiotic stressors such as drought and salinity. Recently, there has been a growing body of research on the mechanisms that allow watermelon to tolerate these stresses and improve crop yield. Generally, cucurbits are beneficial to human health, they provide necessary minerals, fibre, and nutrient components. Therefore, this review demonstrates the cutting edge of using GBS technology to identify genetic design of several features in watermelon to improve abiotic stresses (drought and saline). The application of the GBS technique has provided a distinct advantage in watermelon breeding studies. Based on GBS approach, many new candidate genes in watermelon lines control a variety of traits including saline and drought tolerance, fruit rind color, disease tolerance, nutrient components, size, and fruit shape were discovered. Modern breeding techniques are being used to develop economically viable vegetable crops that will meet customer preferences and needs. Further research is needed to enhance watermelon production.

Grafting techniques are being used to improve economically important horticultural crops including Cucumis melo L. This 2-year study was carried out at Cukurova University, Adana, Turkey. This study aimed to evaluate the effects of grafting using different rootstocks on plant, fruit and seed quality in cantaloupe melons. The double haploid (DH) female (H27) and male (H4) parental lines of Solmaz F₁ (Cucumis melo L. var. cantalupensis) variety developed by Cukurova University Faculty of Agriculture were used as scion and three commercial interspecific hybrid Cucurbita (Cucurbita maxima Duchesne × Cucurbita moschata Duchesne) varieties, Nun-9075 F₁ (Nunhems), Ares F₁ (ITU) and TZ-148 (Clause) were used as rootstocks. The parental lines were also self grafted and ungrafted parents were used as the control group. The grafted and ungrafted parents were crossed during pollination. Graft combinations and control were compared for performances in measured parameters such as the main stem length (cm), main stem diameter (mm), node number, harvest time (day), fruit weight (g), fruit length (cm), fruit diameter (cm), fruit cavity length (cm), fruit cavity diameter (cm), fruit flesh thickness (cm), fruit rind thickness (mm), total soluble solids (TSS, %), fruit flesh productivity (%), number of full and empty seeds (number/fruit), 1000 seeds weight (g), seed germination rate (%) and time (day), seed emergence rate (%), and time (day). Most of the plant, fruit and seed parameters have been positively affected by grafting. The use of commercial interspesific Cucurbita hybrid rootstocks resulted in high values compared to the control group however, harvest time, fruit cavity length and diameter, fruit rind thickness and fuit flesh productivity parameters were not statistically significant between rootstocks. Considering seed emergence and germination rate Cucurbita hybrid rootstocks performed lower values than self grafted and ungrafted control. The current study concludes that grafting plays a crucial role in plant growth, fruit and seed characters in cantaloupe melons. Statistically significant differences were mostly observed based on evaluated parameters.

Verticillium wilt disease in cotton is a soil-borne disease that causes significant yield losses, and it is therefore important to identify disease-resistant genotypes. Current study was carried out in the experimental field of the Faculty of Agriculture, Dicle University (Diyarbakir) in the year 2020 to determine the tolerance levels of some cotton genotypes which contain different characteristics to wilt disease (Verticillium dahliae Kleb.). The experiment area has been naturally infected with Verticillium wilt pathogens. A total of 124 cotton genotypes, including four controls (DP-499, Edessa, ST-468, ES-1), were arranged in five blocks according to the Augmented Design. The indices of stem cross-section and the leaf-disease severity were found significant. The leaf-disease severity varied between 0.12-3.09 at 50-60 % at boll opening period, whilst stem cross-section values ranged between 0.36-2.30. Moreover, a positive correlation was found between the indices. In conclusion, G7, G12, G21, G22, G23, G41, G51, G55, and G101 were determined as tolerant genotypes to Verticillium wilt in terms of examining two parameters.

Current and advanced breeding tools are being used to improve economically important horticultural crops to meet the consumers’ needs and preferences. Genotyping-by-sequencing (GBS) is an extremely useful tool in the investigation and analysis of the genetic diversity of different cultivars. Based on a broad range of genetic backgrounds like single nucleotide polymorphism (SNPs), GBS is known as a novel technique to facilitate the detection of quantitative trait loci (QTL) regions robustly linked with interested traits compared to genome-wide association study (GWAS) and QTL. GBS has gained popularity among breeders in recent years and it is also employed in cucumber breeding programs. Cucumbers (C. sativus L.) are monoecious, gynoecious and some of them are parthenocarpic species. Cucumber is one of the most economical and essential crops in the Cucurbitaceae family. For time immemorial, cucumber has been produced and consumed all over the world like other cucurbits. To a large extent, cultivated cucurbits are beneficial to human health for providing necessary minerals and fibers. Therefore, this review portrays the current status of advances made by using GBS and its combination with other tools in various studies of cucumber such as the use of GBS and single nucleotide polymorphism (SNP) markers, GBS and GWAS, also with QTL and marker-assisted selection (MAS) are applied to display and detect explicit genetic architecture complex traits in crops and chromosome rearrangements. Cucumber breeding programs have undoubtedly benefited from genotyping-by-sequencing. Using the GBS method, research discovered lots of new candidate genes that control various traits including spine color, fruit stalk-end color, and disease resistance in cucumber lines.