Cucurbitaceous Crops Research Articles

Survey on Incidence of Gummy Stem Blight on Watermelon (Citrullus lanatus) in Karnataka, India

Watermelon (Citrullus lanatus) is an important cucurbitaceous crop cultivated worldwide. The cultivation of watermelon and other species of the family Cucurbitaceae is severely affected by several diseases like anthracnose, Alternaria leaf spot, bacterial fruit blotch, powdery mildew and gummy stem blight. Among the diseases, gummy stem blight is an emerging and devastating disease caused by Didymella bryoniae producing a serious threat to the economics of production of cucurbits like watermelon. A roving survey was carried out in eight districts of Karnataka (Chamarajanagara, Chikkaballapura, Gulburga, Vijayapur, Bengaluru urban, Kolar, Mysuru and Yadgiri) from 2021 to 2023 to record the incidence of gummy stem blight (GSB) disease on watermelon. The survey data revealed that GSB disease was observed in all areas. The per cent disease index ranged from 29.6 to 51.2 per cent. The maximum mean per cent disease index of (51.2%),) Bengaluru urban district and the lowest was seen in the Mysuru district (29.6%) followed by Chikkaballapura district (31.0%). The pathogen associated with gummy stem blight disease was isolated and proved the pathogenicity of the isolate and fulfilled the Koch’s postulates.

First report of cucurbit yellow stunting disorder virus causing yellowing disease on major gourds in India

Cucurbitaceous crops are a key group of vegetables widely cultivated in India. Characterized yellowing symptoms along with interveinal chlorosis, mottling and downward curling were observed in ridge gourd, snake gourd, and bottle gourd along with the presence of whiteflies (Bemisia tabaci). To investigate the infecting virus, RT-PCR assays followed by sequencing and Transmission Electron Microscopy (TEM) analysis were performed. Sanger sequencing, nucleotide sequence analysis, and TEM imaging confirmed the association of cucurbit yellow stunting disorder virus (CYSDV), genus Crinivirus within the family Closteroviridae. This study reports the natural occurrence of CYSDV in ridge gourd, snake gourd, and bottle gourd for the first time in India.

Efficacy of Ethephon Doses on Vegetative and Reproductive Attributes of Watermelon [(Citrullus lanatus (Thunb.) Matsum. & Nakai

Watermelon is a widely cultivated cucurbitaceous crop with economic and dietary significance. The plant's ability to reproduce effectively relies on the harmonious growth and maturation of both its male and female flowers. At the farm level, determining the exact amount of ethylene required to regulate the development and sexual expression of individual floral buds remains uncertain, despite the known influence of exogenously applied ethylene on these processes. The goal of the research was to explore how the ethephon doses influence vegetative characteristics, sex expression, and watermelon yield. The experiment, employing a one-factorial Randomized Complete Block Design (RCBD) comprising five treatments and four replications, was conducted in a farmer's field in Buttabari, Jhapa. Using R-stat software, the data were analyzed at a 5% level of significance. Treatment consisted of Ethephon with four doses namely; 100ppm, 200ppm, 300ppm, 400ppm, and a control. Ethephon application was done twice, once at the two true-leaf stages and another at four true-leaf stages. The study revealed that plant height decreased with ethephon compared to the control, reaching a minimum of 280.1 cm at 400 ppm and a maximum of 307.1 cm in the control. Additionally, the highest branch numbers were observed with ethephon at 200 ppm. The plot treated with 200ppm ethephon was found to be more effective than alternative doses at increasing the total number of female flowers, bearing 15.25 female flowers per plant. Control (166.50 per plant) and 400 ppm (150.00 per plant) had the highest and lowest male flower counts per plant, respectively. A maximum yield of 25.12 t/ha and a minimum yield of 19.1 t/ha were determined at 200 ppm and control, respectively. Hence, farmers are found to benefit from ethephon doses of 200 ppm.

In vitro antifungal activities of dose-dependent bioactive compound from potato peels to combat powdery mildew disease in cucumber

The search for biopolymer-based materials to replace dangerous chemicals in agriculture has become increasingly important in recent years for sustainable crop development. In our study enzymatic synthesis of isomaltose was done using potato peels. Isomaltose solvent extracts were tested for their ability to inhibit fungal pathogens like Erysiphe cichoracearum and Fusarium oxysporum. Among those tested, a dosedependent isomaltose extract exhibited significant inhibition on E. cichoracearum and F. oxysporum pathogen conidial sporulation, number of conidia and their motility. Under the in vitro studies, with isomaltose extract at (2.5 mg mL ) recorded a maximum conidial inhibition of 86.2, ?1 E. cichoracearum average number of conidia 4-27 and 5 per cent motility. While, sterile distilled water and DMSO showed maximum growth of the both the pathogens and also their motility was 92-97 per cent, respectively. Similarly, F. oxysporum maximum conidial inhibition of 88.3 and average conidia of 9-30 with motility of 7 per cent was observed after treating with 2.5 mg mL isomaltose. Moreover, isomaltose a biopolymer ?1 derived from potato peel was used in different concentrations as priming agent to cucumber seeds and were evaluated for its effectiveness to enhance plant growth parameters. Among the treatments, seeds-primed with 2.5 mg mL of isomaltose extracts in water exhibited early seedling germination of 96.8 per cent and ?1 vigor of 2210.3 and also cucumber seeds treated with 2.5 mg mL of isomaltose extracts in DMSO showed ?1 significant germination rate of 95.5 per cent and vigor index of 1987.7. Overall, these results determine that the antifungal property of water dissolved isomaltose is highly significant in exhibiting remarkable inhibitory action against Fusarium and powdery mildew phytopathogens, further the dose-dependent concentration of water dissolved isomaltose showed fair to good enhancement of seed germination which will lead to establishing a novel bio-waste agricultural formulation for the management of plant pathogens and in particular Fusarium and powdery mildew disease of cucumber and other cucurbitaceous crops.. KEYWORDS :Bio-polymer, optimize, pathogen inhibition, plant growth, seed treatment

Investigation on disease incidence, distribution and diversity of Begomoviruses infecting cucurbitaceous crops in North Bengal, India

Aim: To study the disease incidence and diversity of Begomovirus infection and crop loss due to spread of virus across different districts of North Bengal. Methodology: Several fields in different districts of North Bengal were surveyed and potential begomoviral-infected samples were collected for further analysis. Total DNA extraction, PCR analysis, sequencing and phylogenetic analysis were conducted. Results: During 2019-2021, ten fields of each district were surveyed and begomoviral occurrence was observed in almost every field. The disease incidence in different districts varied from 15-45%. The highest disease (42.5%) incidence of was observed in the Darjeeling district while the lowest (15%) was recorded from Alipurduar district. The maximum crop loss due to Begomovirus was 64-100% in bitter gourd, 40-80% in cucumber and 20-30% in wax gourd. 153 samples from 6 different cucurbits were collected and analysed. PCR using AV494/AC1048 primers that amplified coat protein region (~550bp) showed 74% of the samples as positive. Upon sequencing and BLAST analysis, ToLCNDV, SLCCV and BGYVV were detected. In phylogenetic analysis, the isolates clustered in three separate clades based on Begomovirus species irrespective of the hosts. Present isolates showed more closeness to Indian and Bangladesh isolates. Interpretation: The documentation of disease severity caused by Begomovirus is of extreme importance for food security of the people. Present study revealed that Begomovirus is present in all the crop field studied. The results indicated an urgent need for the management of the viruses to save crops. Key words: Begomovirus, Cucurbitaceous crops, Disease incidence, North Bengal

First Report of Natural Infection of Watermelon mosaic virus (WMV) Infecting Bottle Gourd and Snake Melon

Cucurbitaceous crops, one of the main crops of agriculture, are sensitive to many plant viruses. In August 2019, virus-like symptoms were observed on some cucurbit plants grown in private home gardens in Antalya and Denizli provinces (Turkey). A total of 53 leaf samples were sampled from plants with the most symptoms (melon (Cucumis melo L.), watermelon (Citrullus lanatus L.), bottle gourd (Lagenaria siceraria (Molina) Standl.), and snake melon (Cucumis melo var. flexuosus) and tested by Reverse-Transcriptase Polymerase Chain Reaction (RT-PCR) against possible watermelon mosaic potyvirus (WMV) infection. The coat protein gene (CP) specific primer sets amplified a gene product of nearly 820 bp fragment from symptomatic plants. WMV infections were detected in 31 individual cucurbit plants, including 11 melons, 8 watermelons, 7 snake melons and 5 bottle gourds. The presence of viral infection was found only in ornamental squash plants in Antalya province and in all cucurbits sampled in Denizli province. To better comprehend the molecular characteristics of virus isolates, the amplified viral DNA fragments were cloned in a proper prokaryotic plasmid, sequenced by Next Generation Sequencing (NGS) and recorded to GenBank. Bioinformatic analyses using the Basic Local Alignment Search Tool (BLAST) showed that the identified CP gene sequences exhibited significant nucleotide homogeneity, supported by a high nucleotide similarity index with that of other isolates around the world. In addition, Turkish isolates isolated from Antalya and Denizli regions showed approximately 94% nucleotide similarity among themselves. For phylogenetic inference, WMV sequences were subjected to multiple alignments with isolates from different geographic origins of the same viruses. Molecular phylogeny showed that all WMV isolates are closely related to other world WMV isolates at variable rates. WMV is wide host range viruses in cucurbit crops, however, this work is the first scientific report of WMV isolates detected in bottle gourd and snake melon from the South and West Regions of Turkey all over the world.WMV are broad spectrum viruses in cucurbit crops. This work is the first scientific report of Watermelon mosaic potyvirus isolates detected in bottle gourd and snake melon from the South-West Region of Turkey in all over the world.

Characterization of multiple disease resistance in melons (Cucumis melo L.) against Meloidogyne incognita, Fusarium oxysporum and tomato leaf curl Palampur virus

AbstractMelon is one of the important cucurbitaceous crops being cultivated widely in India and known for its delicious fruits. Crop is threatened by different biotic stresses including nematodes, fungi and viruses. The use of host resistance is the most economical, eco-compatible and long-lasting strategy to combat plant diseases. Keeping in mind this objective, 64 melon genotypes were screened against the prevalent Meloidogyne incognita, Fusarium oxysporum and tomato leaf curl Palampur virus (ToLCPalV) individually as well as with combined inoculations under artificial conditions. Out of 64 genotypes, three genotypes, MCPS, SM2012-1 and WM11 were found moderately resistant to M. incognita, nine genotypes (MM-KP15103, MM327, MM121103, KP4HM15, MM Sel.-103, SM2013-2, SM2012-1, SM2013-9 and WM11) recorded a resistant reaction against Fusarium wilt while four genotypes, WM11, SM2012-1, SM2013-9 and SM2013-2 exhibited a highly resistant reaction against ToLCPalV. A dendrogram constructed based on the resistance response of all the genotypes divided the genotypes into two groups and all resistant genotypes (MM1804, MM120103, SM2012-1, MM121103, SM2013-2, SM2013-9, WM11 and MM Sel.103) clustered in group II. The resistant genotypes when subjected to simultaneous inoculations of all three pathogens showed an increase in disease severity for each pathogen which negatively altered the resistance response of different genotypes. However, the genotypes SM2012-1, SM2013-9, SM2013-2 and WM-11 showing multiple disease resistance exhibited a good level of resistance even after combined inoculations of three pathogens. This study is the first to our knowledge identifying multiple disease resistance against root-knot nematode, Fusarium wilt and tomato leaf curl Palampur virus in muskmelon.

Inevitable Role of Grafting in Improvement of Cucurbitaceous Crops: A Review

Cucurbit grafting has grown in favour among vegetable gardeners all over the world. The approach was originally developed to prevent soil-borne diseases, which remain still very important in today’s intensive agriculture. Important diseases that can be controlled by utilizing cucurbit rootstocks include fusarium and verticillium wilt, bacterial wilt, phytophthora and root-knot nematode. Demand for vegetables has been tremendously increasing around the world and due to the scarcity of arable land, persistent cultivation of vegetables being done under unfavourable soil and environmental stress conditions, especially in protected cultivation. Hence to lessen the production losses brought on by such abiotic and biotic stresses in cucurbits be to graft them onto rootstocks. Cucurbit grafting has also resulted in the production of organic and environmentally safer produce by reducing the intake of unfavourable pesticide residues. However, due to recent developments, this strategy now multifarious and used for a multitude of things. Increased usage of grafted seedlings will surely be encouraged by the development of versatile rootstocks, effective grafting tools and methods in numerous nations. The current review work highlights numerous studies on cucurbitaceous crop grafting carried out globally on issues including abiotic and biotic stresses, growth, yield and quality of cucurbitaceous crops.Cucurbit grafting has grown in favour among vegetable gardeners all over the world. The approach was originally developed to prevent soil-borne diseases, which remain still very important in today’s intensive agriculture. Important diseases that can be controlled by utilizing cucurbit rootstocks include fusarium and verticillium wilt, bacterial wilt, phytophthora and root-knot nematode. Demand for vegetables has been tremendously increasing around the world and due to the scarcity of arable land, persistent cultivation of vegetables being done under unfavourable soil and environmental stress conditions, especially in protected cultivation. Hence to lessen the production losses brought on by such abiotic and biotic stresses in cucurbits be to graft them onto rootstocks. Cucurbit grafting has also resulted in the production of organic and environmentally safer produce by reducing the intake of unfavourable pesticide residues. However, due to recent developments, this strategy now multifarious and used for a multitude of things. Increased usage of grafted seedlings will surely be encouraged by the development of versatile rootstocks, effective grafting tools and methods in numerous nations. The current review work highlights numerous studies on cucurbitaceous crop grafting carried out globally on issues including abiotic and biotic stresses, growth, yield and quality of cucurbitaceous crops.

Genetic Diversity Analysis of Bitter Gourd (Momordica charantia L.) Germplasm using Molecular Markers

Bitter gourd [Momordica charantia L.] is an important cucurbitaceous crop of medicinal and nutraceutical value. The present study was conducted to compare the efficacy of random amplified polymorphic DNA (RAPD) and inter simple sequence repeats (ISSR) molecular markers for genetic diversity analysis of bitter gourd. Twenty-one genotypes of bitter gourd, collected from different parts of India, were used for diversity analysis using two different types of markers. RAPD and ISSR markers yielded an average of 7.16 and 5.73 amplicon per primer, respectively. In the present study, RAPD and ISSR showed 89 and 63% polymorphic bands, respectively. Combined data analysis of RAPD and ISSR markers provided 73.66% polymorphism with 5.33 polymorphic amplicons per primer. The better discriminatory power of ISSR markers over RAPD markers may be due to comparatively higher values of average polymorphic information content (0.175) as well as the diverse nature of the genotypes. The information generated in this study would be helpful in designing breeding strategies for bitter gourd improvement.

A distinct strain of tomato leaf curl New Delhi virus that causes mosaic disease in ash gourd and other cucurbitaceous crops.

Ash gourd (Benincasa hispida) is a cucurbitaceous crop cultivated as an edible vegetable rich in vitamins, minerals, dietary fibers and antioxidants. In a field survey conducted in the Udumalpet region of Tamil Nadu during 2019, the incidence of mosaic disease on ash gourd crop was observed to be 75%. The DNA-A and DNA-B components of begomovirus genome have been identified as associated with this disease. Both the cloned DNA-A and DNA-B genomic components shared highest pairwise sequence identities with the isolates of tomato leaf curl New Delhi virus (ToLCNDV), a bipartite begomovirus. Recombinant analysis showed that both the components are possibly evolved through intra-species recombination between ToLCNDV isolates. Tomato leaf curl Bangladesh betasatellite (ToLCBB) is not naturally associated with this sample. The results of infectivity studies on ash gourd and other cucurbitaceous crops demonstrates the Koch's postulates, when co-inoculation of DNA-A and DNA-B of ToLCNDV was undertaken. However, the inoculation of non-cognate ToLCBB along with DNA-A and DNA-B enhances the symptom expression and reduces the time taken for symptom development. Thus, Koch's postulates were proved for these virus complexes on cucurbitaceous crops. Furthermore, an enhanced accumulation of DNA-A component was detected in the cucurbits co-inoculated with ToLCNDV and ToLCBB. This report highlights the importance of investigating the spread of these disease complexes with other cucurbitaceous crops in India.

Embryonic microinjection of ribonucleoprotein complex (Cas9+sgRNA) of whitegene in melon fly, Zeugodacuscucurbitae (Coquillett) (Diptera: Tephritidae) produced whiteeye phenotype.

Melon fly, Zeugodacus cucurbitae (Coquillett) is a major pest of cucurbitaceous crops, and causes substantial yield losses and economic costs. CRISPR/Cas9 is a rapid and effective site-specific genome editing tool for the generation of genetic changes that are stable and heritable. The CRISPR/Cas9 tool uses synthetically designed single guide RNA (sgRNA) that is complementary to the target gene and guides the Cas9 enzyme to perform nuclease activity by making double-strand breaks in the target DNA sequences. This tool can be effectively exploited to improve traits critical for the management of insect pests by targeting specific genes encoding these traits without the need of extensive genetic information. The white gene is an important gene responsible for the transport of body pigment precursor molecules. In this study, we produced effective mutagenesis of the white gene of Z. cucurbitae using the CRISPR/Cas9 tool with double sgRNAto target multiple sites of white to increase the efficiency in the generation of frame-shift mutations resulting in the white eye phenotype in adults. This was achieved through embryonic microinjection of the ribonucleoprotein (RNP) complex in the pre-blastoderm embryo stage 1 h after embryo laying. Our success with the production of a white eye mutant fly by CRISPR/Cas9 mutagenesis is important for the research on gene function and protein-level modifications in melon fly and forms the basis for the development of new genetic control strategies such as precision guided sterile insect technique (pgSIT) for this pest of economic significance.

Race Composition of Root Knot Nematode (Meloidogyne ) Species Infecting Cucurbitaceous Crops in Terai region of West Bengal

Race Composition of Root Knot Nematode (Meloidogyne ) Species Infecting Cucurbitaceous Crops in Terai region of West Bengal

Unraveling the devastating impact of Tomato Leaf Curl New Delhi Virus (ToLCNDV): understanding its characteristics, host range, and management strategies

Due to their stagnation, plants are frequently exposed to a variety of stresses, including both abiotic and biotic factors. Biotic stress in plants is due to many microbes that include viruses, fungi, bacteria, and parasitic organisms as plant pathogens. Plant viruses are one of those pathogens that frequently evolve and lower global agricultural productivity. Geminiviruses are the most damaging type of plant viruses. Tomato Leaf Curl New Delhi Virus (ToLCNDV) is a begomovirus belonging to the family Geminiviridae. This is a ssDNA virus having a bipartite genome with genomic length ranging between 2.6-2.7 kb. This virus was originally discovered in India in 1995 from tomato (Lycopersicon esculentum). It mostly infects solanaceous and cucurbitaceous crops and is a whitefly-transmitted, circulative and persistent virus. Its prominent symptoms are severe upward leaf curling, enations, stunting, puckering, yellow spots and yellow mosaic. This virus has devastating effects on the yield of different crops with yield losses ranging between 17.6-99.4 % depending upon the disease-causing factors. ToLCNDV-ES and ToLCNDV-OM are the most devastating strains of this virus. This comprehensive review will provide basic information on the characteristic features of ToLCNDV. The evolutionary mechanism of this virus is studied to know about the strain’s evolution with the passage of time on different host plants cultivated in several regions of the world. This review also covers the genome characteristics, geographical distribution, host range, transmission methods, genetic diversity, different molecular & serological assays, yield losses, and the management of this virus.

Insect Pests of Zucchini and their Natural Enemies

Zucchini (Cucurbita pepo L.) is a trending crop for every health enthusiast today. The market demands for quality zucchini, bearing the best shape and size, free from all blemishes have gone sky high recently. Nevertheless, this cucurbitaceous crop is susceptible to many pests and diseases during its growth period, including its post-harvest life, which bring down the yield both in terms of quality and quantity.The time and intensity of the incidence of the pest varies greatly with crop growth stages. Therefore, an investigation was carried out during 2021-2022, for studying the incidence of various insect pests’ of zucchini and their natural enemies under naturally ventilated polyhouse condition at the experimental farm of Department of Horticulture, Assam Agricultural University, Jorhat, Assam, India. Five insect pests viz., Aleurodicus dispersus Russell, Aphis gossypii Glover, Aulacophora foveicollis Lucus, Bactrocera cucurbitae Coquillett and Pseudodendrothrips species Niwa were found to be very active from October, 2021 till March, 2022. Among them, A. dispersus and A. gossypii caused viral infection (zucchini yellow vein mosaic) in the early vegetative stage whereas B. cucurbitae caused severe damage by distorting and malformation of fruits during the flowering and fruiting stage. Two predators, namely Coccinella transversalis F. and Coccinella septempunctata L. were abundant during the growing period which fed on these insect pests.

Biocontrol of Bacterial Fruit Blotch by Seed Priming with Bacillus Amyloliquefaciens and Pseudomonas Fluorescens

Bacterial fruit blotch (BFB), caused by the seed-transmitted pathogen Acidovorax citrulli, poses a serious threat to cucurbitaceous crops worldwide. In this study, two biocontrol bacteria strains, Bacillus amyloliquefaciens (Ba- 2) and Pseudomonas fluorescens (2P24), with significant antagonistic activity against A. citrulli were and applied by seed priming to control BFB seed transmission. Artificially infested watermelon and melon seeds were treated with the biocontrol strains by liquid or solid matrix seed priming. The seed bio-priming effects were evaluated under greenhouse conditions. Germination percentages were improved by seed priming treatments for melon, and seedling uniformity was higher for seeds primed with Ba-2 than for seeds from the other treatments for watermelon. Seedling disease incidence of untreated seeds were 6.5% for watermelon and 16.0% for melon, and water-priming resulted in similar disease progress curves as the untreated control. Seed priming with Ba-2 and 2P24 significantly reduced seedling BFB incidence for both watermelon and melon. Evaluation with naturally infested watermelon seeds primed with biocontrol strains indicated that 2P24 seed priming was more effective than Ba-2 ( P < 0.05) and 2P24 solid matrix priming, reducing the seedling disease incidence to 1.3%. Seed bio-priming has potential as an effective and eco-friendly approach for suppressing bacterial fruit blotch seed-to-seedling transmission.

Fusaricidin produced by the rhizobacterium Paenibacillus polymyxa NX20 is involved in the biocontrol of postharvest plant-pathogenic oomycete Phytophthora capsici

Phytophthora capsici is a destructive oomycete pathogen that mainly threatens solanaceous and cucurbitaceous vegetable crops, resulting in severe economic losses annually. Paenibacillus polymyxa, a typical biological control agent (BCA), has been widely used to control plant diseases due to its efficacy and environmentally friendly properties. However, the application of P. polymyxa to control pathogenic oomycete P. capsici during the postharvest period has not been reported. In this study, we found that P. polymyxa NX20 exhibited the best inhibitory effect on the mycelial growth of P. capsici among 160 cultivable isolates, and the lipopeptide fusaricidin was the main factor in its antagonistic action. Fusaricidin exhibited good inhibition activity against P. capsici with an EC50 value of 2.46 mg L−1. Both zoospore production and germination were suppressed by fusaricidin in a dose-dependent manner. According to the microscopy observation and cell membrane permeability assay, fusaricidin was proved to impaired the plasma membrane structure and led to cell death in P. capsici. Additionally, after exposure to fusaricidin, the reactive oxygen species accumulation was induced and DNA/protein synthesis was inhibited in P. capsici. RNA-Seq analysis revealed that fusaricidin treatment could potentially affect plasma membrane integrity, transmembrane transport, energy metabolism, and signal transduction in P. capsici. Furthermore, fusaricidin exhibited good control efficacy against P. capsici on watermelon, pepper, and cherry tomato fruit. Overall, these findings elucidated the anti-oomycete mechanism of fusaricidin and highlighted the potential of P. polymyxa strain NX20 on vegetable protection and preservation.

Studies on viral diseases of bitter gourd (Momordica charantia L.) with reference to their eco-friendly management in Eastern U.P.

In the northern regions of India, throughout the warm season and the rainy season, one of the most significant cucurbitaceous vegetable crops that is cultivated is the bitter gourd, which is scientifically known as (Momordica charantia L). It is cultivated all over the world, both in tropical and subtropical regions, and possesses a large genetic variety. However, “the crop is affected by a number of diseases, including anthracnose, powdery mildew, downy mildew, Cercospora leaf spot, Alternaria leaf blight, and anthracnose leaf spot. Of these diseases, the leaf spot caused by Alternaria spp. is found to cause serious losses throughout Uttar pradesh and other states”. Other diseases include powdery mildew, downy mildew, and powdery mildew. The survey was carried out during the vegetative stage and the fruiting stage of the crop during both the kharif and the rabi seasons by visually inspecting the plants in each field in a “W” pattern. These crop growth stages occur throughout a single cropping season (crossing the rows). According to the findings of the study, the occurrence “of whiteflies and viral illnesses in bitter gourd was seen in all of the investigated areas with varying levels of damage and vulnerability. This was the case in all of the locations”.

3G Cutting: An Innovative Tool in Cucurbitaceous Crops to Boost the Production and Doubling the Income of Small Farmers in a Per Unit Area

3G cutting is one of the most popular and successful inter-culture operations in cucurbitaceous crops like; bottle gourd, cucumber, pumpkin, sponge gourd, bitter gourd, etc. as well as in plants like tomato, eggplant, chilli, and lady’s finger for a small patch of land. Low fruit set is an emerging constraint in cucurbits, and when it does, extremely small-sized fruits develop and degrade the mother plant. This is the main problem that farmers are currently facing. This problem arises due to a rapid decrease in beneficial insects and other pollinators as a result of the haphazard use of foliar fertilizers and chemical pesticides. 3G cutting is a scientific process to get higher production from plants by increasing the number of female flowers in the plant by adopting practices like trimming and pruning of 1st and 2nd generation branches. Generally, 1G and 2G branches have more no. of male flowers than female (approximately in the ratio of 14:1) whereas this ratio is reduced to 1:2 in 3G branches. We are all known that fruits develop from female flowers, while one male flower can pollinate several female flowers. However, this does not imply that there is no need for male flowers. Male flowers are necessary for pollination. Thus, 3G cutting is the finest scientific practice for farmers to maximize the number of female flowers and fruit yield.

Genetics of downy mildew resistance in indigenous cucumber germplasm

Cucumber (Cucumis sativus L.) is a major Cucurbitaceous vegetable crop widely grown in tropical andsubtropical regions of the world. Downy mildew is the most damaging disease in cucumber worldwide causingsignificant yield loss. The wide diversity in terms of different economically important traits including severityto downy mildew infestation is available in Indian-originated germplasm. To investigate the genetic inheritanceof cucumber downy mildew disease resistance, one resistant genotype (DC-70) from India was crossed with acontrasting susceptible genotype (DC-773). The parents and their progenies were evaluated in both field andnet house conditions for downy mildew disease resistance. Field condition data were recorded 4-times from30 days until the plants die. The lower leaf surface was inoculated 20-25 days after sowing at the seedlingstage by spraying the inoculum. The proportion of infection was recorded 4-times from 8-days to 65-daysafter inoculation, and the per cent disease index and area under the disease progress curve (AUDPC) werecalculated from these proportions. Based on the PDI and AUDPC, it was established that resistance to downymildew in the genotype, DC-70 was controlled by a major gene. Additive-dominance model fits the segregationdata and the additive effect was significant. Finally, the downy mildew disease inheritance pattern indicatedthat it is controlled by a single recessive gene in DC-70, which can be successfully introgressed into desiredelite genotypes to facilitate the downy mildew resistance breeding programme.

Molecular mapping of genomic regions and identification of possible candidate genes associated with gynoecious sex expression in bitter gourd

Bitter gourd is an important vegetable crop grown throughout the tropics mainly because of its high nutritional value. Sex expression and identification of gynoecious trait in cucurbitaceous vegetable crops has facilitated the hybrid breeding programme in a great way to improve productivity. In bitter gourd, gynoecious sex expression is poorly reported and detailed molecular pathways involve yet to be studied. The present experiment was conducted to study the inheritance, identify the genomic regions associated with gynoecious sex expression and to reveal possible candidate genes through QTL-seq. Segregation for the gynoecious and monoecious sex forms in the F2 progenies indicated single recessive gene controlling gynoecious sex expression in the genotype, PVGy-201. Gynoecious parent, PVGy-201, Monoecious parent, Pusa Do Mausami (PDM), and two contrasting bulks were constituted for deep-sequencing. A total of 10.56, 23.11, 15.07, and 19.38 Gb of clean reads from PVGy-201, PDM, gynoecious bulk and monoecious bulks were generated. Based on the ΔSNP index, 1.31 Mb regions on the chromosome 1 was identified to be associated with gynoecious sex expression in bitter gourd. In the QTL region 293,467 PVGy-201 unique variants, including SNPs and indels, were identified. In the identified QTL region, a total of 1019 homozygous variants were identified between PVGy1 and PDM genomes and 71 among them were non-synonymous variants (SNPS and INDELs), out of which 11 variants (7 INDELs, 4 SNPs) were classified as high impact variants with frame shift/stop gain effect. In total twelve genes associated with male and female gametophyte development were identified in the QTL-region. Ethylene-responsive transcription factor 12, Auxin response factor 6, Copper-transporting ATPase RAN1, CBL-interacting serine/threonine-protein kinase 23, ABC transporter C family member 2, DEAD-box ATP-dependent RNA helicase 1 isoform X2, Polygalacturonase QRT3-like isoform X2, Protein CHROMATIN REMODELING 4 were identified with possible role in gynoecious sex expression. Promoter region variation in 8 among the 12 genes indicated their role in determining gynoecious sex expression in bitter gourd genotype, DBGy-1. The findings in the study provides insight about sex expression in bitter gourd and will facilitate fine mapping and more precise identification of candidate genes through their functional validation.