Genetic Analysis of the First Female Flower Node and the First Male Flower Node in Bitter Gourd

Exploring genetic mechanism of the first female flower node and the first male flower node in bitter gourd has practical significance for formulating breeding strategy. In this article, a cross was made between CN19-1 and Thai4-6, and the F2segregation population was also constructed through F1selfing. The genetic characteristics of the first female flower node and the first male flower node were analyzed by adopting the major gene plus polygene mixed genetic model. The data analysis results showed that the first female flower node and the first male flower node were continuous distribution in the F2segregation population. E-2 model was the most suitable model for the genetic analysis of the first female flower node and the first male flower node. The additive effect values of the 2 pairs of major genes controlling the first female flower node were 2.722 and 1.862 8 respectively, the dominant effect values were-2.721 6 and-0.171 8, respectively. The additive effect value of polygene was-0.839 2, and the dominant effect value of polygene was 2.225 4. The heritability of major genes and polygene were 83.73% and 1.54%, respectively. The additive effect values of the 2 pairs of major genes controlling the first male flower node were 17.746 9 and 3.972, respectively, the dominant effect values were 5.191 6 and-3.972, respectively. The additive effect value of polygene was-20.530 5, and the dominant effect value was-4.141 4. The heritability of major genes and polygene was 92.34% and 4.7%, respectively. This study could provide a theoretical basis for bitter gourd breeding.

Whole-genome sequencing provides insights into the genetic diversity and domestication of bitter gourd(Momordica spp.)

Bitter gourd(Momordica charantia)is a popular cultivated vegetable in Asian and African countries.To reveal the characteristics of the genomic structure,evolutionary trajectory,and genetic basis underlying the domestication of bitter gourd,we performed whole-genome sequencing of the cultivar Dali-11 and the wild small-fruited line TR and resequencing of 187 bitter gourd germplasms from 16 countries.The major gene clusters(Bi clusters)for the biosynthesis of cucurbitane triterpenoids,which confer a bitter taste,are highly conserved in cucumber,melon,and watermelon.Comparative analysis among cucurbit genomes revealed that the Bi cluster involved in cucurbitane triterpenoid biosynthesis is absent in bitter gourd.Phylogenetic analysis revealed that the TR group,including 21 bitter gourd germplasms,may belong to a new species or subspecies independent from M.charantia.Furthermore,we found that the remaining 166 M.charantia germplasms are geographically differentiated,and we identified 710,412,and 290 candidate domestication genes in the South Asia,Southeast Asia,and China populations,respectively.This study provides new insights into bitter gourd genetic diversity and domestication and will facilitate the future genomics-enabled improvement of bitter gourd.

Isolation and Identification of Fusarium Wilt Pathogens from Bitter Gourd in Hainan Province

In order to isolate and identify the pathogens causing Fusarium wilt in bitter gourd in Hainan Province, China, four bitter gourd plants exhibiting symptoms of Fusarium wilt were collected from Tunchang County, Hainan Province. Four pathogen strains （HNTC-01, HNTC-02, HNTC-03 and HNTC-04） were isolated from the four plants, and identified via morphological observation and molecular techniques. The results showed that HNTC--01, HNTC-03 and HNTC-04 were F. oxysporum, while HNTC-02 was F. graminearum. The tests on pathogenicity and host specificity showed that HNTC-01, HNTC-03 and HNTC-04 were F. oxysporum Schl. f. sp. momordicae. Phylogenetic analysis revealed that HNTC-01, HNTC-03, HNTC-04 were clustered together with 14 strains of F. oxysporum, and HNTC-02 was clustered together with six strains of F. graminearum. In addition, rDNA-ITS region can be used to distinguish different Fusarium species, but can not be used to distinguish different biotypes within a Fusarium species. This study could provide a scientific basis for the diagnosis and prevention of wilt in bitter gourd.

Identification and Evaluation of Cold Tolerance in Bitter Gourd (Momordica charantia L.) at Bud and Seedling Stages under Different Temperature Conditions

[ Objectives] This study was conducted to screen the temperature index most suitable for identification of cold tolerance in bitter gourd （Momordica charantia L. ） at bud and seedling stages. [ Methods] With six different bitter gourd germplasms as experimental materials, the cold tolerance at bud and seedling stages were identified and evaluated. [ Results] At 18℃ , the largest change range of germination potential among different gernlplasms was 11.3% -96.0%, and the largest change range of germination rate was 13.3% - 100.0% ; and the six germplasms could be divided into three grades of cold tolerance. Therefore, 18 9C is an ideal temperature for the identification of cold tolerance in bitter gourd germplasms at bud stage. At 20℃, the cold tolerance in bitter gourd germplasms at bud stage could also be divided into three grades, and the change ranges of germination potential and germination rate were larger than 50.0%, so 20℃ could serve as the candidate temperature for the identification of cold tolerance in bitter gourd germplasms at bud stage. After 1 d of treatment at 6℃, the six bitter gourd germplasms could be divided into three grades, and the cold injury index had the largest range of 20.31 - 84.38 and could serve as the temperature index for the identification of cold tolerance in bitter gourd at seedling stage. [ Conclusions] This study will provide reference for the identification of cold tolerance in bitter gourd at bud stage and seedling stage.

Fusarium Wilt Resistance Identification and Genetic Analysis of Momordica charantia L. Germplasm

Fusarium wilt seriously affects the yield and quality of Momordica charantia L.Breeding resistant varieties is the most economical and effective measure to control Fusarium wilt in M.charantia L.This study had comprehensively conducted pathogen identification of Fusarium wilt,resistance evaluation of M.charantia L.germplasm to Fusarium wilt,and genetic analysis of Fusarium wilt resistance in M.charantia L.,so as to provide reference for breeding resistant varieties and accelerating the breeding process.

The Variety Screening of Green-stem Non-heading Chinese Cabbage and Dark-green-leaf Non-heading Chinese Cabbage Tolerant to Heat

[Objectives] Introducing and screening leaf vegetable varieties tolerant to heat and humidity has great significance to ensure balanced supply of vegetables in summer and autumn in Hainan Province. [Methods] On the basis of the introduction of green-stem non-heading Chinese cabbage and dark-green-leaf non-heading Chinese cabbage varieties, the varieties tolerant to heat and humidity were identified by the investigation of agronomic traits and evaluation of heat injury index. [Results] The data analysis results showed that four green-stem non-heading Chinese cabbage varieties including Huaguan Qingcaigeng F_1, Zhongguan Qinggeng, Hanshen No. 1 Qinggengcai F_1 and Huaxiawang Piaocai have the characteristics of strong tolerance to heat and high yield, and four dark-green-leaf non-heading Chinese cabbage varieties including Baimeigui, Heijingang, Xiaxue Naibaicai and Siji Baicai have the characteristics of strong tolerance to heat and high yield. [Conclusions] These eight leaf vegetable varieties are suitable for popularization in summer and autumn in Hainan Province.

Genetic Diversity Analysis of Cherry Tomato Core Collection Based on Genotypic Values

Taking 65 cherry tomato core germplasms as experimental materials,the genetic diversity of seven agronomic traits were analyzed.The correlation between any two of the seven agronomic traits and the genetic relationships of these germplasms were analyzed based on genotypic values.The genetic diversity indices of the seven agronomic traits were 4.15,4.13,4.16,4.13,4.13,4.13 and 4.01,respectively,showing that the cherry tomato core collection had abundant genetic diversity.The correlation analysis between traits based on genotype effect values showed that leaf length was significantly correlated with leaf width with the correlation coefficient of 0.56.The fruit width was significantly correlated with fruit length with the correlation coefficient of 0.52.The flesh thickness was significantly correlated with fruit length and fruit width with the correlation coefficients of 0.49 and 0.39,respectively.The single fruit weight was significantly correlated with fruit length,fruit width and flesh thickness with the correlation coefficients of 0.44,0.61 and 0.62,respectively.When the genetic distances between core germplasms of cherry tomato were calculated based on the phenotypic values,65 core germplasms of cherry tomato were divided into three groups with the rescaled distance of 10.When the genetic distances between core germplasms of cherry tomato were calculated based on the genotypic values,the 65 core germplasms of cherry tomato were divided into four groups with the rescaled distance of 10.Comparing the 2 clustering results,it could find that genotypic value-based clustering analysis could better clarify the genetic relationship between core germplasms.This study could provide a theoretical basis for the effective utilization of cherry tomato core germplasms.

GC-MS Analysis of Liposoluble Components in Seeds of Bitter Gourd from Different Sources

[Objectives]This paper aimed to analyze the liposoluble components in seeds of different bitter gourd germplasms.[Methods]Taking 3 bitter gourd germplasms from different sources as materials,the composition and relative contents of liposoluble components in the seeds were analyzed using gas chromatography-mass spectrometry(GC-MS).[Results]A total of 22,18 and 18 compounds were detected from Papua,Y7 and Y108,respectively,accounting for 38.63%,90.20%and 92.53%of the total liposoluble components.Among them,eight liposoluble components were unique to Papua,and two liposoluble components were unique to Y108.The composition and relative contents of liposoluble components differ among different bitter gourd germplasms.The main chemical components wereγ-tocopherol,vitamin E,andβ-tocopherol.The content ofγ-tocopherol was high in the three germplasms,accounting for 8.885%,20.090%and 20.314%,respectively.[Conclusions]This study can lay the foundation for breeding functional bitter gourd varieties.

Identification and Evaluation of Resistance to Meloidogyne incognita in Bitter Gourd Germplasms

[ Objective] This study aimed to identify and evaluate the resistance of bitter gourd germplasms to Meloidogyne incognita. [ Method] A total of 71 bit-ter gourd germplasms were artificially inoculated with M. incognita at seedling stage to investigate the effects of M. incognita on resistance indexes of bitter gourd seedlings. Cluster analysis and subordinate function analysis were performed to identify and evaluate the resistance of experimental materials. [ Result] The infec-tion of M. incognita increased the variation coefficients of resistance indexes. The resistance to M. incognita varied significantly among different bitter gourd germ- plasms. Based on gall index, 71 bitter gourd germplasms were divided into five types by cluster analysis, including resistant materials, moderately resistant materi-als ,moderately susceptible materials, susceptible materials and highly susceptible materials. The subordinate function analysis showed that total subordinate func-tion values of Y107, Y109, Y108, Y51, Y105, Y81, Y89, Y140 and Y94 exceeded 1.95 , indicating high resistance to M. incognita. [ Conclusion] This study could provide resistant materials for breeding root-knot nematode resistant varieties of bitter gourd.

Genetic Diversity and Correlation Analysis of Main Botanical Traits of Chili Pepper Genetic Resources

A total of 398 chili pepper germplasms were used as test materials and genetic diversity and correlation analysis were performed on 17 botanical traits. The results of diversity analysis showed that the diversity indexes of the 17 botanical traits ranged from 0.15 to 5.97 with the average value of 4.12. The data distributions of 11 quantitative traits were more dispersed than qualitative traits. The average value of eoefficient of variation was 36.90% and the variation ranges were one to six times larger than the average value. The results of correlation analysis showed that plant height had significantly positive correlations with plant breadth, leaf length, leaf width, petiole length, the frrst flower node and carpopodium length. The In＇st flower node was significantly negatively correlated with fruit length, fruit width, flesh thickness and weight per fruit and signifieantly positively correlated with plant height and plant breadth. The flesh thickness was significantly positively correlated with leaf length, leaf width, petiole length, fruit length, fruit width and carpopodium length. The weight per fruit was significantly positively correlated with leaf length, leaf width, petiole length, fruit length, fruit width, carpopodium length and flesh thickness. Materials with low first flower node, moderate plant height and width and large fruit should be selected for the breeding of early-maturing and high-yield chili pepper varieties. The genetic distances between chili pepper traits were calculated based on the genotypic values of the 11 quantitative traits. The genetic distances between different traits ranged from 14.26 to 32.99. The 11 quantitative traits were divided into seven groups when the rescaled distance was ten, which further clarified the relationships between different traits. The research results laid a solid foundation for the new variety breeding of chili pepper.

Effects of Grafting on Volatile Compounds in Bitter Gourd Fruit

[Objectives]This study was conducted to explore the effects of grafting on volatile compounds in bitter gourd fruit.[Methods]The volatile compounds and relative contents of grafted and non-grafted fruit were analyzed by headspace solid phase micro-extraction with gas chromatography-mass spectrometry.[Results]There were 59 volatile compounds in Haiyan No.2S,including six unique compounds.There were 58 volatile compounds in Haiyan No.2J,including five unique compounds.[Conclusions]This study provides a scientific basis for further analysis of bitter gourd flavor regulation mediated by grafting.

Genetic Analysis of Leaf Length and Leaf Width in Bitter Gourd

[Objectives]To explore the genetic mechanism that leaf length and leaf width in bitter gourd has realistic guiding significance for formulating breeding strategy.[Methods]In this paper,the cross was made between CN19-1 and Thai4-6 and an F2segregation population was constructed.The genetic characteristics of leaf length and leaf width were analyzed by employing the major gene plus polygene mixed genetic model.[Results]The data analysis results demonstrated that the leaf length and leaf width of the F_(2) segregation population showed continuous distribution.The optimum model for leaf length genetic analysis was A-1,the additive effect value of the major gene was 3.1766,the dominant effect value was-3.1766,and the heritability was 74.51%.The optimum model for leaf width genetic analysis was B-1.The additive effect values of 2 pairs of major genes controlling the leaf width were 3.1917 and 0.9623,respectively.The dominant effect values were-1.3135 and-0.3463,respectively.The additive×additive interaction effect was-0.3591,the additive×dominant interaction effect was-0.2570,the dominant×additive interaction effect was 1.9916,the dominant×dominant interaction effect was 1.9686.The heritability of major genes was 96.67%.[Conclusions]This study is expected to provide a theoretical basis for the breeding of bitter gourd.

Genetic Analysis of Weight per Fruit and Fruit Length in Bitter Gourd

[Objectives]The paper was to verify the genetic mechanism of weight per fruit and fruit length in bitter gourd and to provide guidance for formulating breeding strategy.[Methods]In this study,a cross was made between CN19-1 and Thai4-6,and a Fsegregation population was also constructed.The genetic characteristics of weight per fruit and fruit length were analyzed by employing major gene plus polygene mixed genetic model.[Results]The weight per fruit and fruit length showed continuous distribution in Fsegregation population.The optimal model for weight per fruit and fruit length was the same(A-1 model).The major gene additive effect value of weight per fruit was 46.1474,the dominant effect value was-46.1005,and the major gene heritability was 52.47%.The major gene additive effect value of fruit length was 2.456,the dominant effect value was-2.455,and the major gene heritability was 52.52%.The results showed that weight per fruit and fruit length were mainly controlled by a pair of major genes.[Conclusions]This study can provide a theoretical basis for bitter gourd breeding.

Genetic Variation Analysis of Watermelon Genomes with Different Ploidy

120 pairs of SSR primers and 63 pairs of In Del primers were used to determine genetic variation among diploid,triploid and tetraploid watermelon genomes. The results showed that 113 pairs of SSR primers and 63 pairs of In Del primers could be successfully amplified.There was slight difference between diploid and tetraploid watermelon genomes in the aspect of SSR. Among 120 pairs of SSR primers,2 showed obvious polymorphism with polymorphic rate of 1. 67%,corresponding to 34047313-34063581 intervals on chromosome 9. 1 gene encoding zinc finger protein was predicted in polymorphic interval which could regulate the expression of other genes at the level of transcription and translation. There was no significant difference in the aspect of In Del among watermelon genomes with different ploidy which indicated that the genomic insertion and deletion site was not changed before and after chromosome doubling. The results indicated that watermelon genomic structure had no significant change in the process of polyploidization. The difference of traits between tetraploidy and diploid parent might be closely related with epigenetic regulation. This study could provide scientific basis for ploidy breeding,new variety improvement and germplasm innovation.

Screening of Bitter Gourd Hybrid Combinations with High Yield and Disease Resistance

[Objectives]This study was conducted to breed and promote high-yield and disease-resistant varieties of bitter gourd.[Methods]The comparison experiments of six new hybrid combinations(Z1705,Z1706,Z1717,Z1721,Z1732,Z1745)were successively carried out at two experimental sites of Danzhou and Tunchang.[Results]Comparing the agronomic traits and disease resistance of various combinations,it was concluded that Z1717 and Z1721 have high yields,green and glossy fruit surface and good comprehensive disease resistance,so they can be popularized and planted.[Conclusions]This study is of great significance for improving the yield of bitter gourd and increasing economic benefits.

Genetic Mapping of Root-knot Nematode Resistance Genes in Solanaceous Vegetables

Root-knot nematodes are becoming more and more harmful to solanaceous vegetables. The most economical and effective way to deal with root-knot nematode disease is to breed varieties with disease resistance. This paper reviewed the recent research progress and achievements of tomato, pepper, eggplant and potato on root-knot nematode disease resistance gene characteristics, disease resistance gene mapping and disease resistance gene molecular markers, and prospects for future research directions.

Study on Cold Tolerance Identification Indices for Bitter Gourd Germplasms

The selection of cold tolerance identification indices for bitter gourd germplasms is an important basis for the breeding of cold-tolerant bitter gourd varieties. In this study, with six bitter gourd germplasms as experimental materials, the cold injury index of bitter gourd was analyzed under low temperature treatment, the changes in physiological indices were revealed, and the main agronomic traits were measured. The results showed that the cold injury index of bitter gourd was in very significant negative correlation with SOD activity, POD activity and PRO content, in significant negative correlation with CAT activity, in very significant negative correlation with flowering node and commodity rate, but in significant positive correlation with female flower ratio. It was found that that cold injury index, SOD activity, POD activity, CAT activity and PRO content could serve as the cold tolerance identification indices for bitter gourd at seedling stage, and flowering node and commodity rate could be used as the auxiliary indices for field cold tolerance identification.

Grafting and Seedling Cultivation Technology of Cherry Tomato for Disease Prevention in Hainan

In order to reduce the occurrence of soil-borne diseases,such as tomato bacterial wilt and Fusarium wilt,and to improve the yield of cherry tomato in Hainan,the paper had summarized grafting and seedling technology of cherry tomato from the aspects of rootstock selection,rootstock seedling cultivation,scion seedling cultivation,preparation before grafting,grafting method and seedling management after grafting.It was found that the technique could significantly improve the yield and disease resistance of cherry tomato.

Grafting and Seedling Cultivation Technique of Bitter Gourd for Disease Prevention in Hainan

The paper had introduced the operation technical regulations of bitter gourd grafting and seedling cultivation,including all kinds of measures before,during and after grafting,in order to provide technical reference for efficient production of bitter gourd.

The Genetic Analysis of Internode Length in Bitter Gourd

Performing the genetic mechanism research of internode length in bitter gourd has important guiding significance for making breeding strategy. A cross was made between CN19-1 and Thai4-6, and an F2 segregation population was constructed. The genetic characteristic of the internode length was analyzed through employing the major gene plus polygene mixed genetic model. The results showed that the internode length was continuous distribution in the F2 population. The optimum model for internode length genetic analysis was B-1. The additive effect values of two pairs of major genes controlling the internode length were 3.206 3 and 2.638 3, respectively, which showed a positive effect. The dominant effect values were-3.434 6 and-1.459 6, respectively, which showed a negative effect. The dominant degree of major genes is-1.07 and-0.55, respectively, indicating that the first pair of major genes was over dominant and the second pair of major genes was incompletely dominant. The heritability of the major gene was 82.25%, indicating the genetic stability was high. This study could provide a theoretical reference for the breeding of bitter gourd.