Explore the vast range of titles available.

Cucurbit crops comprise ∼25% of the vegetable acreage in the mid-Atlantic and Northeastern United States. However, options for postemergence weed control in these crops are limited. Overlapping herbicides is a technique that involves sequential applications of soil-applied residual herbicides to lengthen herbicidal activity before the first herbicide dissipates. Residual herbicides such as S -metolachlor will not control emerged weeds, but weed control efficacy may be extended if these herbicides are applied after crop emergence, but before weed emergence occurs. Currently S- metolachlor is not labeled for broadcast applications over cucurbit crops. Greenhouse studies were conducted to evaluate pumpkin, cucumber, and summer squash variety response to varying S- metolachlor rates. S -metolachlor was applied at 1.42 and 2.85 lb/acre at the two-leaf stage of pumpkin and 0.71, 1.42, 2.85, and 5.7 lb/acre at the two-leaf stage of cucumber and summer squash. Cucumber showed a greater response to S- metolachlor with up to 67% injury observed at 5.70 lb/acre. S- metolachlor applications to pumpkin and summer squash resulted in less than 6% injury, regardless of application rate or crop variety. S- metolachlor applied at 2.85 lb/acre reduced pumpkin and cucumber dry weight 6% and 19%, respectively, but did not reduce squash dry weight. S- metolachlor reduced cucumber dry weight 78% for all varieties. Pumpkin varieties ‘Munchkin’ and ‘Baby Bear’ exhibited a 23% difference in dry weight, but no other differences were observed among other varieties because of S -metolachlor applications. Summer squash varieties ‘Respect’ and ‘Golden Glory’ exhibited a 31% difference in dry weight, but no other differences were observed among other varieties. Results show that pumpkin and summer squash demonstrated good crop safety when S- metolachlor was applied as a broadcast treatment after crop emergence. However, caution should be urged when applying this herbicide to cucumber.

Although crop wild ancestors are often reservoirs of resistance traits lost during domestication, examining diverse cultivated germplasm may also reveal novel resistance traits due to distinct breeding histories. Using ten cultivars from two independent domestication events of Cucurbita pepo (ssp. pepo and texana), we identified divergences in constitutive and induced resistance measured by growth of generalist caterpillars and leaf traits. C. p. texana cultivars were consistently more resistant to Trichoplusia ni and Spodoptera exigua, and this was not due to expected mechanisms including cucurbitacins, nitrogen, sticky phloem sap, or toxicity. Although more susceptible on average, C. p. pepo cultivars showed stronger induced resistance, suggesting a trade-off between constitutive and induced resistance. To test the hypothesis that leaf volatiles accounted for differences in resistance to caterpillars, we devised a novel method to evaluate resistance on artificial diet while larvae are exposed to leaf volatiles. In both subspecies, cultivar-specific induced volatiles that reduced T. ni growth were present in highly inducible cultivars, but absent in those that showed no induction. These results have important agricultural implications as cultivar-specific resistance to caterpillars mirrored that of specialist beetles from field trials. Overall, the eponymous cucurbitacin defenses of the Cucurbitaceae are not the mechanistic basis of differences in constitutive or induced resistance between C. pepo subspecies or cultivars. Instead, deterrent cultivar-specific volatiles appear to provide general resistance to insect herbivores. Divergence during breeding history within and between subspecies revealed this pattern and novel resistance mechanism, defining new targets for plant breeding.

Phytoextraction, utilizing plants to remove soil contaminants, is a promising approach for environmental remediation but its application is often limited due to the long time requirements. This study aims to develop simplified and user-friendly probabilistic models to estimate the time required for phytoextraction of contaminants while considering uncertainties. More specifically we: i) developed probabilistic models for time estimation, ii) applied these models using site-specific data from a field experiment testing pumpkin ( Cucurbita pepo ssp . pepo cv. Howden) for phytoextraction of DDT and its metabolites (ΣDDX), iii) compared timeframes derived from site-specific data with literature-derived estimates, and iv) investigated model sensitivity and uncertainties through various modelling scenarios. The models indicate that phytoextraction with pumpkin to reduce the initial total concentration of ΣDDX in the soil (10 mg/kg  dw ) to acceptable levels (1 mg/kg  dw ) at the test site is infeasible within a reasonable timeframe, with time estimates ranging from 48–123 years based on literature data or 3 570–9 120 years with site-specific data using the linear or first-order exponential model, respectively. Our results suggest that phytoextraction may only be feasible at lower initial ΣDDX concentrations (< 5 mg/kg  dw ) for soil polishing and that alternative phytomanagement strategies should be considered for this test site to manage the bioavailable fraction of DDX in the soil. The simplified modes presented can be useful tools in the communication with site owners and stakeholders about time approximations for planning phytoextraction interventions, thereby improving the decision basis for phytomanagement of contaminated sites.

Grafting is a technique commonly used in horticulture to minimize damage from soil-borne diseases and bolster plants’ ability to withstand stress, ultimately resulting in increased plant productivity. Cucurbit plants are frequently grafted for these purposes, and their seeds are widely used as nuts, food additives, and for medicinal properties worldwide. However, no information is available on the impact of grafting on the seed and oil yield and properties of medicinal pumpkins. This study is the first to investigate the effect of grafting on medicinal pumpkin ( Cucurbita pepo var. styriaca) seeds’ yield and oil properties. Commercial medicinal pumpkins were grafted onto five different rootstocks ( C . pepo hybrids) including: ‘code 11’, ‘code 36’, ‘code 45’, ‘code 42’ and ‘code 21’) using three different grafting methods (Side grafting, Hole insertion grafting and cleft grafting). The results showed that the type of rootstock and grafting method significantly affected fruit yield, seed yield, oil yield, and oil qualities. The research revealed that there were no issues with graft incompatibility between the rootstock and medicinal pumpkins. Side-grafting was identified as the most successful method, and these plants were utilized in farm experiments. Furthermore, the rootstocks had a notably positive impact on the success rate, with code 42, code 45, and code 21 rootstocks demonstrating the highest percentage of successful grafts. Medicinal pumpkin ( Cucurbita pepo var styriaca ) plants grafted through the side grafting technique on code 45 hybrids have demonstrated the highest yield and optimal oil properties. Thus, these grafted plants are highly recommended for the commercial production of medicinal pumpkins.

Cucurbita pepo is one of the earliest cultivated crops. It is native to Central and South America and is now widely cultivated all over the world for its rich nutrition, short growth period, and high yield, which make it suitable for intercropping. Hull-less C. pepo L. (HLCP) is a rare variant in nature that is easier to consume. Its seed has a seed kernel but lacks a seed coat. The molecular mechanism underlying the lack of seed coat development in the HLCP variety is not clear yet. The BGISEQ-500 sequencing platform was used to sequence 18 cDNA libraries of seed coats from hulled C. pepo (CP) and HLCP at three developmental stages (8, 18, and 28 days) post-pollination. We found that lignin accumulation in the seed coat of the HLCP variety was much lower than that of the CP variety. A total of 2,099 DEGs were identified in the CP variety, which were enriched mainly in the phenylpropanoid biosynthesis pathway, amino sugar, and nucleotide sugar metabolism pathways. A total of 1,831 DEGs were identified in the HLCP variety and found to be enriched mainly in the phenylpropanoid biosynthesis and metabolism pathways of starch and sucrose. Among the DEGs, hub proteins (FusA), protein kinases (IRAK4), and several transcription factors related to seed coat development (MYB, bHLH, NAC, AP2/EREBP, WRKY) were upregulated in the CP variety. The relative expression levels of 12 randomly selected DEGs were determined using quantitative real-time PCR analysis and found to be consistent with those obtained using RNA-Seq, with a correlation coefficient of 0.9474. We found that IRAK4 protein kinases, AP2/EREBP, MYB, bHLH, and NAC transcription factors may play important roles in seed coat development, leading to the formation of HLCP.

This study investigated the influence of cadmium (Cd) and copper (Cu) heavy metals on germination, metabolism, and growth of zucchini seedlings ( Cucurbita pepo L.). Zucchini seeds were subjected to two concentrations (100 and 200 μM) of CdCl 2 and CuCl 2 . Germination parameters, biochemical and phytochemical attributes of embryonic axes were assessed. Results revealed that germination rate remained unaffected by heavy metals (Cd, Cu). However, seed vigor index (SVI) notably decreased under Cd and Cu exposure. Embryonic axis length and dry weight exhibited significant reductions, with variations depending on the type of metal used. Malondialdehyde and H 2 O 2 content, as well as catalase activity, did not show a significant increase at the tested Cd and Cu concentrations. Superoxide dismutase activity decreased in embryonic axis tissues. Glutathione S -transferase activity significantly rose with 200 μM CdCl 2 , while glutathione content declined with increasing Cd and Cu concentrations. Total phenol content and antioxidant activity increased at 200 μM CuCl 2 . In conclusion, Cd and Cu heavy metals impede zucchini seed germination efficiency and trigger metabolic shifts in embryonic tissue cells. Response to metal stress is metal-specific and concentration-dependent. These findings contribute to understanding the intricate interactions between heavy metals and plant physiology, aiding strategies for mitigating their detrimental effects on plants.

Fruit shape index (round shape) and seed size have important effects on pumpkin yield. To investigate these traits and to create the most desirable state, a cross was made between two pumpkin cultivars. This study aimed to estimate the main gene effects (additive, dominant and di-genic epistasis) and to determine the mode of inheritance for fruit shape and seed size by generation mean analysis. Six generations, namely P1, P2, F1, F2, BC1, and BC2 from a cross between Zucchini and hull-less seed Pumpkin, S10 × P25, were constructed and evaluated for fruit length, fruit width, fruit shape index, and some seed-related traits (seed length, seed width, and seed thickness). The experiment was conducted in the research field of the Faculty of Agricultural Science, University of Guilan, Rasht, Iran in 2019. Results showed a significant difference between generations in terms of fruit and seed traits. Scale and joint scale tests showed the presence of epistasis for some traits. According to the results of the average traits of different generations, standard heterosis and hetrobeltiosis were observed. Concerning the fruit shape index and seed width, there was a dominance effect. The broad-sense heritability of the traits was relatively high for all traits and between 52 and 94%. Narrow sense heritability was between 26 and 90% and relatively low for the fruit shape index and seed width. Therefore, selection of elite lines and production of their hybrids are recommended as two methods suitable for breeding to achieve a round shape index and a larger seed size.

Fruit peel color is a major factor that influences fruit quality and customers’ demand. However, the molecular mechanisms underlying the green fruit peel color trait of Cucurbita pepo L. remain unknown. Two parental lines, RP16 and RP38, were used to study the fruit peel color trait in C. pepo . The parental line RP16 shows white peel color, whereas RP38 exhibits green peel color. 384 F 2 populations were used to identify the inheritance pattern associated with green fruit and white fruit peel in Cucurbita pepo L. 293 F 2 individuals were white, and 91 F 2 individuals were green, resulting in a ratio of 3:1. Hence, white peel is dominant over the green fruit peel trait, and a single recessive green peel gene ( Cpgp ) controls the green fruit peel. The fruit chlorophyll (Chll) content decreases as fruit matures in the RP16 line. In contrast, Chll increases during the fruit growing periods on fruit peels of the RP38 line. The BSA-sequence analysis revealed the Cpgp locus on Chr5, within a 2.3 Mb region. Subsequent fine-mapping analysis, using 699 F 2 plants, narrowed down this region to 23.90 kb on the same chromosome. Within this region, two annotated genes, namely Cp4.1LG05g02070 and Cp4.1LG05g02060 , are present. These genes are predicted to encode a two-component Arabidopsis Pseudo-Response Regulator 2-like protein (APRR2), which may be involved in green pigmentation processes in plants. Consequently, sequence alignment and gene expression analyses at various fruit development stages supported that Cp4.1LG05g02070 may be the primary candidate gene responsible for regulating the green fruit peel color trait in Cucurbita pepo L. This study may provide a basis for further study on the basic mechanisms that control the fruit peel colors in Cucurbita spp .

Summer squash, the young fruits of Cucurbita pepo, are a common, high-value fruit vegetable. Of the summer squash, the zucchini, C. pepo subsp. pepo Zucchini Group, is by far the most cosmopolitan. The zucchini is easily distinguished from other summer squash by its uniformly cylindrical shape and intense colour. The zucchini is a relatively new cultivar-group of C. pepo, the earliest known evidence for its existence having been a description in a book on horticulture published in Milan in 1901. For this study, Italian-language books on agriculture and cookery dating from the 16th to 19th centuries have been collected and searched in an effort to follow the horticultural development and culinary use of young Cucurbita fruits in Italy. The results indicate that Cucurbita fruits, both young and mature, entered Italian kitchens by the mid-16th century. A half-century later, round and elongate young fruits of C. pepo were addressed as separate cookery items and the latter had largely replaced the centuries-old culinary use of young, elongate bottle gourds, Lagenaria siceraria Allusion to a particular, extant cultivar of the longest fruited C. pepo, the Cocozelle Group, dates to 1811 and derives from the environs of Naples. The Italian diminutive word zucchini arose by the beginning of the 19th century in Tuscany and referred to small, mature, desiccated bottle gourds used as containers to store tobacco. By the 1840s, the Tuscan word zucchini was appropriated to young, primarily elongate fruits of C. pepo The Zucchini Group traces its origins to the environs of Milan, perhaps as early as 1850. The word zucchini and the horticultural product zucchini arose contemporaneously but independently. The results confirm that the Zucchini Group is the youngest of the four cultivar-groups of C. pepo subsp. pepo but it emerged approximately a half-century earlier than previously known.