Search

Ribosomal DNAs and various banding patterns are landmarks in molecular cytogenetics providing useful information for karyotyping and addressing individual chromosomes. Bottle gourd is the only cultivated species of the Lagenaria genus with high genetic diversity. After CMA3/DAPI fluorochrome banding we investigated the GC- and AT-rich regions in interphase nuclei of five different local accessions. Fluorescence in situ hybridization (FISH) was conducted to determine the number and location of 45S and 5S rDNAs in bottle gourd. Our results showed four strong CMA3 regions in interphase and on mitotic metaphase chromosomes. FISH revealed four strong signals of 45S rDNA at the termini of two metaphase chromosome pairs and terminal 5S rDNA signals at another pair of chromosomes. The presence of four positive CMA3 bands colocalizes with four 45S rDNA signals in all bottle gourd accessions. Our results allow distinguishing two out of eleven chromosome pairs of bottle gourd.

SUMMARY: The bottle gourd (Lagenaria siceraria, Cucurbitaceae) is an important horticultural crop exhibiting tremendous diversity in fruit shape. The genetic architecture of fruit shape variation in this species remains unknown. We assembled a long‐read‐based, high‐quality reference genome (ZAAS_Lsic_2.0) with a contig N50 value over 390‐fold greater than the existing reference genomes. We then focused on dissection of fruit shape using a one‐step geometric morphometrics‐based functional mapping approach. We identified 11 quantitative trait loci (QTLs) responsible for fruit shape (fsQTLs), reconstructed their visible effects and revealed syntenic relationships of bottle gourd fsQTLs with 12 fsQTLs previously reported in cucumber, melon or watermelon. Homologs of several well‐known and newly identified fruit shape genes, including SUN, OFP, AP2 and auxin transporters, were comapped with bottle gourd QTLs. [ABSTRACT FROM AUTHOR]

Recently, research on the exploitation and conversion of agricultural residues into value added products for the production of various important biomolecules of economic importance has been actively implemented. Therefore, the modification of bottle gourd (Lagenaria vulgaris) shell (BGS), as a potentially valuable agro-waste, by a green carbonate treatment has been analyzed in this study. The biochemical composition, structural and morphological changes of BGS biomass during the treatment were monitored using physicochemical, spectroscopic (FTIR) and microscopic (SEM) methods. The partial delignification and removal of extractive substances from the lignocellulosic biomass, such as oligosaccharides of depolymerized hemicellulose, organic acids, lignin fragments, and possibly trapped minerals have been disclosed. In this way, increased porosity of the cellulose enriched BGS biomass, as well as the activation of cellulosic microfibrils to alkaline-cellulose has been achieved. It was found that these changes are an important prerequisite for making a precursor of biosorbent which can be applied in wastewater treatment technology.

Bottle gourd [Lagenaria siceraria (Molina) Standl.] is an important multi-purpose cucurbit crop grown for its leaf, fruit, and seed. It is widely cultivated and used for human consumption in sub-Saharan Africa (SSA) providing vital human nutrition and serving as food security crop. There is wide genetic variation among bottle gourd genetic resources in Africa for diverse qualitative and quantitative attributes for effective variety design, product development, and marketing. However, the crop is under- researched and -utilized, and improved varieties are yet to be developed and commercialized in the region. Therefore, the objective of this review is to provide the progress on bottle gourd genetic improvement and genetic analysis targeting agronomic and horticultural attributes, nutritional composition, biotic, and abiotic stress tolerance to guide current and future cultivar development, germplasm access, and conservation in SSA. The first section of the paper presents progress on breeding of bottle gourd for horticultural traits, agronomic performance, nutritional and anti-nutritional composition, and biotic and abiotic stress tolerance. This is followed by important highlights on key genetic resources of cultivated and wild bottle gourd for demand driven breeding. Lastly, the review summaries advances in bottle gourd genomics, genetic engineering and genome editing. Information presented in this paper should aid bottle gourd breeders and agronomists to develop and deploy new generation and promising varieties with farmer- and market -preferred attributes.

Fusarium wilt (FW) is a typical soil-borne disease that seriously affects the yield and fruit quality of bottle gourd. Thus, to improve resistance to FW in bottle gourd, the genetic mechanism underlying FW resistance needs to be explored. In this study, we performed a genome-wide association study (GWAS) based on 5,330 single-nucleotide polymorphisms (SNPs) and 89 bottle gourd accessions. The GWAS results revealed a total of 10 SNPs (P ≤ 0.01, −log10P ≥ 2.0) significantly associated with FW resistance that were detected in at least two environments (2019DI, 2020DI, and the average across the 2 years); these SNPs were located on chromosomes 1, 2, 3, 4, 8, and 9. Linkage disequilibrium (LD) block structure analysis predicted three potential candidate genes for FW resistance. Genes HG_GLEAN_10001030 and HG_GLEAN_10001042 were within the range of the mean LD block of the marker BGReSe_14202; gene HG_GLEAN_10011803 was 280 kb upstream of the marker BGReSe_00818. Real-time quantitative PCR (qRT-PCR) analysis showed that HG_GLEAN_10011803 was significantly up-regulated in FW-infected plants of YD-4, Yin-10, and Hanbi; HG_GLEAN_10001030 and HG_GLEAN_10001042 were specifically up-regulated in FW-infected plants of YD-4. Therefore, gene HG_GLEAN_10011803 is likely the major effect candidate gene for resistance against FW in bottle gourd. This work provides scientific evidence for the exploration of candidate gene and development of functional markers in FW-resistant bottle gourd breeding programs.

Fusarium wilt (FW) is a typical soil-borne disease that seriously affects the yield and fruit quality of bottle gourd. Thus, to improve resistance to FW in bottle gourd, the genetic mechanism underlying FW resistance needs to be explored. In this study, we performed a genome-wide association study (GWAS) based on 5,330 single-nucleotide polymorphisms (SNPs) and 89 bottle gourd accessions. The GWAS results revealed a total of 10 SNPs (P ≤ 0.01, −log10 P ≥ 2.0) significantly associated with FW resistance that were detected in at least two environments (2019DI, 2020DI, and the average across the 2 years); these SNPs were located on chromosomes 1, 2, 3, 4, 8, and 9. Linkage disequilibrium (LD) block structure analysis predicted three potential candidate genes for FW resistance. Genes HG_GLEAN_10001030 and HG_GLEAN_10001042 were within the range of the mean LD block of the marker BGReSe_14202; gene HG_GLEAN_10011803 was 280 kb upstream of the marker BGReSe_00818. Real-time quantitative PCR (qRT-PCR) analysis showed that HG_GLEAN_10011803 was significantly up-regulated in FW-infected plants of YD-4, Yin-10, and Hanbi; HG_GLEAN_10001030 and HG_GLEAN_10001042 were specifically up-regulated in FW-infected plants of YD-4. Therefore, gene HG_GLEAN_10011803 is likely the major effect candidate gene for resistance against FW in bottle gourd. This work provides scientific evidence for the exploration of candidate gene and development of functional markers in FW-resistant bottle gourd breeding programs. [ABSTRACT FROM AUTHOR]

A devastating complex pathological condition involving a blend of symptoms such as profuse gum exudation from the stem and slow vine decline; sudden and complete death of vines; and foliar spots progressing into blight in bottle gourd fields was observed for the first time during the year Kharif 2013–14 in Indian Punjab. Over the last five years, this problem has become widespread to emerge as one of the major limitations for bottle gourd cultivation. Through systematic studies, the pathogenesis of three simultaneously occurring syndromes in bottle gourd viz. stem gummosis and slow vine decline; quick wilting and leaf blight were deciphered and their primary etiological causes were established. Pathogenicity tests were conducted to prove Koch postulates and identification of organisms was done through morphological as well as molecular studies. The causal organism of stem gummosis and slow vine decline was established as Fusarium verticillioides (Sacc.) Nirenberg. The pathogen associated with quick wilting was identified as Fusarium oxysporum Schltdl. and the pathogen associated with leaf blight was identified as Lasiodiplodia theobromae (Pat.) Griffon & Maubl. This is the first study to decipher three different diseases caused by three distinct pathogens leading to wilt or blight type symptoms. [ABSTRACT FROM AUTHOR]

Grafting can improve the resistance of watermelon to soil-borne diseases. However, the molecular mechanism of defense response is not completely understood. Herein, we used a proteomic approach to investigate the molecular basis involved in grafted watermelon leaf defense against Fusarium oxysporum f.sp. niveum (FON) infection. The bottle gourd rootstock-grafted (RG) watermelon seedlings were highly resistant to FON compared with self-grafted (SG) watermelon plants, with a disease incidence of 3.4 and 89%, respectively. Meanwhile, grafting significantly induced the activity of pathogenesis-related proteases under FON challenge. Proteins extracted from leaves of RG and SG under FON inoculation were analyzed using two-dimensional gel electrophoresis. Thirty-nine differentially accumulated proteins (DAPs) were identified and classified into 10 functional groups. Accordingly, protein biosynthetic and stress- and defense-related proteins play crucial roles in the enhancement of disease resistance of RG watermelon seedlings, compared with that of SG watermelon seedlings. Proteins involved in signal transduction positively regulated the defense process. Carbohydrate and energy metabolism and photosystem contributed to energy production in RG watermelon seedlings under FON infection. The disease resistance of RG watermelon seedlings may also be related to the improved scavenging capacity of reactive oxygen species (ROS). The expression profile of 10 randomly selected proteins was measured using quantitative real-time PCR, among which, 7 was consistent with the results of the proteomic analysis. The functional implications of these proteins in regulating grafted watermelon response against F. oxysporum are discussed.

Grafting can improve the resistance of watermelon to soil-borne diseases. However, the molecular mechanism of defense response is not completely understood. Herein, we used a proteomic approach to investigate the molecular basis involved in grafted watermelon leaf defense against Fusarium oxysporum f.sp. niveum (FON) infection. The bottle gourd rootstock-grafted (RG) watermelon seedlings were highly resistant to FON compared with self-grafted (SG) watermelon plants, with a disease incidence of 3.4 and 89%, respectively. Meanwhile, grafting significantly induced the activity of pathogenesis-related proteases under FON challenge. Proteins extracted from leaves of RG and SG under FON inoculation were analyzed using two-dimensional gel electrophoresis. Thirty-nine differentially accumulated proteins (DAPs) were identified and classified into 10 functional groups. Accordingly, protein biosynthetic and stress- and defense-related proteins play crucial roles in the enhancement of disease resistance of RG watermelon seedlings, compared with that of SG watermelon seedlings. Proteins involved in signal transduction positively regulated the defense process. Carbohydrate and energy metabolism and photosystem contributed to energy production in RG watermelon seedlings under FON infection. The disease resistance of RG watermelon seedlings may also be related to the improved scavenging capacity of reactive oxygen species (ROS). The expression profile of 10 randomly selected proteins was measured using quantitative real-time PCR, among which, 7 was consistent with the results of the proteomic analysis. The functional implications of these proteins in regulating grafted watermelon response against F. oxysporum are discussed. [ABSTRACT FROM AUTHOR]

The field experiment was conducted (2016-18) at Varanasi, Mirzapur and Deoria districts of Uttar Pradesh with a view to study the validation and economic viability of adaptable IPM technology in a farmers’ led approach. The IPM technology that synthesized comprising seed treatment with Trichoderma viride @5 g/kg of seed; installation of cue lure traps (MAT) for fruit flies @10/acre; raking of soil for exposing fruit fly pupae and removal of weeds, need based application of Bacillus thuringiensis @2 g/litre against Sphenerches caffer; need based spraying of Azadirachtin based neem insecticide @10 ml/litre and Imidacloprid 17.8SL @0.33 ml/litre of water for mirid bugs and whiteflies; fungicide Cymoxanyl 8WP+Mancozeb 64WP @2.5 g/litre against downy mildew were found effective in reducing the incidence of pests and minimizing the yield losses. The adoption of IPM technology, apart from lowering the incidence of major pests, also resulted in reducing the number of chemical sprays to 5–7 from 14–18 in non-IPM fields in a season with higher bottle gourd yields of 28, 29.5 and 21.7 tonnes/ha in IPM and 17.5, 18.1 and 10.9 tonnes/ ha in non-IPM fields and with marginally higher cost benefit ratio of 1:1.91, 1:2.05 and 1:2.41 in IPM than 1:1.14, 1:1.19 and 1:11, respectively in non-IPM. On an average, IPM farmers had an average net return of ₹ 145472/ha with C:B ratio of 1:2.09 as compared to the non-IPM farmers with net return of ₹ 20992/ha with a C:B ratio of 1:1.15.

The genetic parameters were studied to elucidate the genetic variability, correlation and path co-efficient analysis in thirty-nine genotypes of bottle gourd [Lagenaria siceraria (Mol.) Standl] in randomized complete block design with three replications. Observations were recorded for eleven quantitative characters viz., days to first male flower open, days to first female flower open, node number of first female flower, braches plant-1, days to harvest, number of fruits plant-1, fruit weight, fruit length, fruit girth, 100 seed weight and yield ton ha-1. The analysis of variance showed highly significant differences for all the characters studied indicating considerable variability among the genotypes. The highest GCV (35.57%) and PCV (35.62%) were observed for fruit length. The differences between GCV and PCV were high for fruit number plant-1 and days to first male flower open indicating environmental influences. High heritability associates with high estimates of genetic advance in percent of mean were noted for length of fruit, yield, girth of fruit and number of fruits plant-1. It indicated presence of additive gene effect and selection for these traits would be effective. Yield were positively and significantly correlated with fruit weight, 100 seed weight, branch plant-1 and number of fruits plant-1 .Negative associations of yield were noted with days to first male and female flower open, days to harvest and length of fruit. Path analysis revealed that fruits plant-1 (0.93) and weight of fruit (0.467) had very high positive effect on fruit yield ton ha-1 .

A considerable interest has developed on natural foods preservatives as extend the shelf-life. There is a strong controversy about the safety aspects of synthetic preservatives since they are considered responsible for many teratogenic attributes and carcinogenic as well as residual toxicity. Therefore, the antimicrobial activity, total phenolic and flavonoids of bottle ground leaf extract were examined. And a descriptive detection of the extract was made, where it was found that they contain (phenols, flavonoids, alkaloids, glycosides, terpenes, saponins, phlobatanins, resins, tannins And steroids). 50% ethanolic extract exhibited the highest extraction ability for such phenolic and flavonoid compounds. The total phenolic was 406 mg gallic equivalent/g and the total flavonoid was 42.6 mg quercetin/g dry weight. The antimicrobial activity was studied using Agar well diffusion method and broth dilution method. Results indicated that Gram-negative bacteria E. Coli was more sensitive than Gram-positive bacteria S. aureus and B. subtilis against bottle ground leaf extract, were 25, 18 and 19 mm inhibitory zone for concentration 50mg/well respectively. MIC and MLC where determined, MICs test showed that the lowest concentration was 10 mg/ml against S. aureus, and was equal concentration on E. coli and B. subtilis (20 mg/ml). On the basis of this results bottle ground leaf extract was added to beef sausage at different concentrations (1%, 2%, and 4%) and stored for 90 days at -20°C to study its effect on the quality of beef sausage. Results indicated a high stability against oxidation in sausage treated with the bottle ground leaf extract compared to control samples. Also, a decrease in microbial load of the treated sausage compared to the control was observed. Finally, it was evident that the bottle gourd leaf extract has a role in reducing the number of microbes, as well as their possession of natural antioxidants that prolongs shelf life of sausage. [ABSTRACT FROM AUTHOR]

Grafted seedlings are used not only for protection from soil-borne diseases but also to increase tolerance to abiotic stress conditions, improve fruit quality and increase nutrient uptake in the soil. In this study, it was aimed to determine the effect of different watermelon rootstocks on weight loss of watermelon fruits, which were obtained at deficit irrigation levels and they were stored under controlled conditions for different periods. For this purpose, 2 citron watermelons, 1 open bottle gourd and 1 hybrid TZ-148 which is widely used for watermelon in Turkey were used as rootstock. The "Crimson Tide" commercial cultivar was grafted onto these rootstocks and non-grafted applications were used as control lots. 5 different irrigation levels were applied according to the plant pan coefficient such as kcp1 = 1.00 (I100), kcp2 = 0.75 (I75), kcp3 = 0.50 (I50), kcp4 = 0.33 (I33) and kcp5 = 0.00 (I0) non-irrigated. According to the results, all watermelon rootstocks caused by less fruit weight loss compared to non-grafted applications and it has been demonstrated that using grafted rootstocks is an advantage in watermelons to be stored. On the other hand, TZ-148 commercial rootstock and citron melon 1 rootstock determined as the best rootstock in post-harvest storage. The I100 and I75 irrigation levels have approximately the same weight loss. [ABSTRACT FROM AUTHOR]

Gummy stem, sudden death and leaf blight diseases are newly emerging, concurrently occurring, serious problems of bottle gourd in northern India. Due to the unavailability of resistance sources against these diseases, chemical management is the only viable option against this disease complex. Bio-efficacy of systemic and non-systemic fungicides as foliar, soil drench and as combination of foliar with soil drench is reported against these three diseases under in vitro as well as field conditions. Under in vitro, conditions carbendazim was the most effective against Fusarium verticillioides (ED50 0.25 μg mL-1) and Fusarium oxysporum (ED50 0.21 µg mL-1), the causal agents of gummy stem disease and sudden death respectively, whereas, combi-product of trifloxystrobin + tebuconazole (1:2) was the most effective against Lasiodiplodia theobromae (ED500.28 μg mL-1) incitant of leaf blight. Under field conditions, three applications of carbendazim 50 WP @ 0.2 per cent as soil drench around the vine base along with foliar application of tebuconazole 25 EC @ 0.1 per cent concentration at fortnightly interval starting from last week of July proved to be the most effective against gummy stem disease and sudden death. Against leaf blight, three foliar applications of propiconazole 25 EC @ 0.1 per cent were the most effective. [ABSTRACT FROM AUTHOR]

Grafting is a basic technique which is widely used to increase yield and enhance biotic and abiotic stress tolerance in plant production. The diversity and interactions of rhizobacterial assemblages shaped by grafting are important for the growth of their hosts but remain poorly understood. To test the hypothesis that plant grafting shapes complexity and co-occurrence of rhizobacterial assemblage, four types of plants, including ungrafted bottle gourd (B), ungrafted watermelon (W), grafted watermelon with bottle gourd rootstock (W/B), and grafted bottle gourd with watermelon rootstock (B/W), were cultivated in two soil types in a greenhouse, and the rhizosphere bacterial communities were analyzed by 16S rRNA gene high-throughput sequencing. Both the soil type and grafting significantly influenced the bacterial community composition. Grafting increased bacterial within-sample diversity in both soils. Core enriched operational taxonomic units (OTUs) in the W/B rhizosphere compared with the other three treatments (B, W, and B/W) were mainly affiliated with Alphaproteobacteria, Deltaproteobacteria, and Bacteroidetes, which are likely related to methanol oxidation, methylotrophy, fermentation, and ureolysis. Co-occurrence network analysis proved that grafting increased network complexity, including the number of nodes, edges, and modules. Moreover, grafting strengthened the structural robustness of the network in the rhizosphere, while ungrafted watermelon had the lowest network robustness. Homogeneous selection played a predominant role in bacterial community assembly, and the contribution of dispersal limitation was increased in grafted watermelon with bottle gourd rootstock. Grafting increased the diversity and transformed the network topology of the bacterial community, which indicated that grafting could improve species coexistence in the watermelon rhizosphere. [ABSTRACT FROM AUTHOR]

This article addresses the technical and cost competitiveness of microfiltration and centrifugation to produce organic clarified bottle gourd juice. The microfiltration (MF) process was conducted for fresh and centrifuged juices and for transmembrane pressures ranging from 103.4 to 172.4 kPa. Pertinent flux decline was extensively analyzed to account for the extent of irreversible membrane fouling using resistances in series model, flux decline, and recovery ratios. Feed, centrifuged, and permeate juice samples were evaluated for nutritional content and physico-chemical parameters to affirm that MF of fresh juice is the best among all investigated cases. Compared with the centrifugation process, the MF process performed comparatively better in terms of cost competitiveness, juice clarity, microbial, and protein rejection. For a variation in juice production capacity of 110–10,000 L, the MF-based juice processing cost varied from 1.19 to 0.37 $/L, which accounts to 31.27–26.32% of fresh juice cost to infer upon promising performance of the low-cost ceramic membranes. [ABSTRACT FROM AUTHOR]

Antituberculosis drug-indced hepatotoxicity is the most serious and potentially fatal adverse reaction. The purpose of the study was to evaluate the hepatoprotective activity of Lagenaria siceraria fruit peel extract against antitubercular drugs (INH + RIF+ PYZ) induced hepatotoxicity in rats. Liver toxicity was induced by anti-tubercular drugs (INH + RIF + PYZ) at dose level of (30+60+150) mg/kg each, p.o. for 30 days. Ethanolic extract of Lagenaria siceraria at a dose of 200mg/kg and 400mg/kg were administered orally once daily for 30 days. The hepatoprotective activity was assessed using various biochemical parameters SGPT, SGOT, ALP, LDH, Bilirubin, Albumin, Total cholesterol and Total protein. Obtained results demonstrated that the treatment with Lagenaria siceraria significantly (P<0.01) and (P<0.001) and dose dependently prevented drug induced increase in serum levels of hepatic enzymes. Histopathology of liver tissue showed that Lagenaria siceraria attenuated the hepatocellular necrosis, regeneration and repair of cells toward normal. [ABSTRACT FROM AUTHOR]

Bottle gourd (Lagenaria siceraria (Molina) Standl.) is a significant cucurbit plant species whose ripe fruits are consumed as ornamental items and immature fruits are consumed as vegetables. In addition, these plants are used as rootstocks in vegetable grafts due to their strong root structure. This study aimed to determine the genetic diversity of bottle gourd genotypes whose fresh fruits are consumed. Using iPBS (Inter-Primer Binding Site) retrotransposon marker techniques, a total of 186 bands in 30 genotypes were obtained and the polymorphism rate was calculated as 93.3%. Similarity coefficient values were found in the range of 0.35-0.96. Three main clusters emerged from cluster analysis. As a result of the structure analysis, genotypes were divided into four subpopulations. There was also a high level of genetic diversity among bottle gourd genotypes. To improve a variety's traits, genetic diversity can be used. The iPBS technique is also a powerful tool for understanding the genetic characterization of bottle gourd. These data can be used in breeding strategies to improve bottle gourd varieties. [ABSTRACT FROM AUTHOR]

Fruit bitterness is a serious problem threatening the bottle gourd (Lagenaria siceraria [Mol.] Standl.) industry worldwide. Previous genetic studies indicated that fruit bitterness in the bottle gourd was controlled by a pair of complementary genes. In this study, based on two non-bitter landraces “Hangzhou Gourd” and “Puxian Gourd,” each of which carries a single bitterness gene, and their derived segregation populations, we mapped the complementary genes causing fruit bitterness. Quantitative trait locus (QTL) scanning based on an F2 population detected two QTLs, which was QBt.1 locating in a 17.62-cM interval on linkage group (LG)2 corresponding to a 1.6-Mb region on chromosome 6, and QBt.2 mapped to a 8.44-cM interval on LG9 corresponding to a 1.9-Mb region on chromosome 7. An advanced bulked segregant analysis (A-BSA) well validated the QTL mapping results. Sequence-based comparative analysis showed no syntenic relationship between QBt.1/QBt.2 and the known bitterness genes in cucumber, melon, and watermelon, suggesting that causal genes underlying QBt.1 and QBt.2 were not direct orthologs of the reported cucurbit bitterness genes. Our results shed light on the molecular genetic mechanisms underlying fruit bitterness in the bottle gourd and is useful to guide breeders to properly select parental lines to avoid the occurrence of bitter fruits in breeding programs.

Low yield of bottle gourd (Lagenaria siceraria L.) in Pakistan can be attributed to number of factors, however, cultivation of low-yielding cultivars is a serious and an important issue. Yield in bottle gourd can be improved by using adaptable high-yielding cultivars. The present investigation was carried out with ten cultivars of bottle gourd to evaluate their performance for various horticultural attributes. Cultivars grown under agro-climatic conditions of Faisalabad exhibited significant variation in number of horticultural attributes. The genotype G6 (Akash Green gold) was found to possess maximum internodal length (3.61 cm) while, G2 (Arya 187 F1) recorded maximum leaf area (89.29 cm2). The cultivar G4 (Akash F1 hybrid) and G8 (Kohli Long hybrid) was noted for higher fruit diameter (11.96 cm) and fruit length (13.23 cm), respectively. The cultivar G2 (Arya 187 F1) was found to be superior and promising for more fruit weight, higher number of fruits per vine and elevated fruit yield, thus it can be recommended to farmers for commercial cultivation. Moreover, outcome of this bottle gourd characterization exhibiting signi?cant variations can be organized in accordance to their usefulness for identi?cation of morphological traits, fruit characters and seed attributes.

Fruit bitterness is a serious problem threatening the bottle gourd (Lagenaria siceraria [Mol.] Standl.) industry worldwide. Previous genetic studies indicated that fruit bitterness in the bottle gourd was controlled by a pair of complementary genes. In this study, based on two non-bitter landraces "Hangzhou Gourd" and "Puxian Gourd," each of which carries a single bitterness gene, and their derived segregation populations, we mapped the complementary genes causing fruit bitterness. Quantitative trait locus (QTL) scanning based on an F2 population detected two QTLs, which was QBt.1 locating in a 17.62-cM interval on linkage group (LG)2 corresponding to a 1.6-Mb region on chromosome 6, and QBt.2 mapped to a 8.44-cM interval on LG9 corresponding to a 1.9-Mb region on chromosome 7. An advanced bulked segregant analysis (A-BSA) well validated the QTL mapping results. Sequence-based comparative analysis showed no syntenic relationship between QBt.1/QBt.2 and the known bitterness genes in cucumber, melon, and watermelon, suggesting that causal genes underlying QBt.1 and QBt.2 were not direct orthologs of the reported cucurbit bitterness genes. Our results shed light on the molecular genetic mechanisms underlying fruit bitterness in the bottle gourd and is useful to guide breeders to properly select parental lines to avoid the occurrence of bitter fruits in breeding programs. [ABSTRACT FROM AUTHOR]

An experiment was carried out to analyze genetic variability for yield and its contributing characters in 20 bottle gourd genotypes in Randomized Block Design (RBD) with three replication to assess the nature and magnitude of association among yield and its contributing traits in bottle gourd. Analysis of variance revealed that there were significant differences among the genotypes studied for all the characters except node number of first female flower. Moderate differences between phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) indicating the least role of environment on these traits. Among these characters, vine length, fruit girth, days to fruit harvest and node number of first female flower registered high genotypic variability suggesting their improvement through selection. High heritability was recorded for all the characters except average fruit weight. Traits like vine length, node number of first male flower, node number of first female flower, fruit length, fruit girth, number of fruits per vine, 100 seed weight and yield per vine shows high heritability along with high genetic gain which reveals the predominance of additive gene action of these traits. [ABSTRACT FROM AUTHOR]