Fruit Flesh Color Research Articles

Identification of chromosome region and candidate genes for canary-yellow flesh (Cyf) locus in watermelon (Citrullus lanatus)

Genetic control of fruit flesh color in watermelon is complex, and significant knowledge gaps still exist. In the present study, we investigated the genetic basis of canary-yellow flesh color in watermelon inbred line PI 635597 using a segregating population derived from a cross between PI 635597 and another inbred line, Cream of Saskatchewan (pale yellow flesh color). We showed that a single dominant gene controls the canary-yellow flesh color for the Cyf (canary-yellow flesh) trait. Bulk segregant analysis (BSA) and fine genetic mapping narrowed down the Cyf locus to a 79.62-kb region on chromosome 6, which harbors 10 predicted genes. Sequence variation analysis in the promoter and coding regions and gene expression analysis in both parental lines and selected watermelon accessions with diverse fruit flesh colors support Cla97C06G122050 (unknown protein) and Cla97C06G122120 (pentatricopeptide repeat) as predicted candidate genes for the Cyf locus. Marker-assisted selection and sequence alignment showed that the Cyf locus could differentiate canary-yellow flesh and pale-yellow flesh. Our results indicate that the Cyf locus might be responsible for canary-yellow flesh color and carotenoid accumulation levels.

Quality Performance of Some Local Pear Cultivars on BA29 Rootstock under High Density Planting

The study aimed to assess the fruit quality characteristics of some local pears grafted on BA29 quince clone rootstock in 2021 and 2022. Pomological, chemical and sensory analyzes were carried out to evaluate fruit quality characteristics. All examined pomological properties were found to be statistically significant. The fruit weight (195.47 g), fruit width (73.56 mm), fruit height (73.72 mm), fruit stalk thickness (3.94 mm) and fruit volume (193.30 ml) of the ‘Karpuz’ pear were higher than the other cultivars. The highest fruit length (90.96 mm) and fruit stalk length (40.22 mm) in the ‘Eşek’ pear; the highest flesh firmness (9.35 kg cm-2) was determined in the ‘Harman’ pear. The total Soluble solid (TSS) content of the ‘Kara’ and ‘Rıza’ pears was higher (16.83% and 16.50%) than the other cultivars. In the color of the fruit skin; the highest L* value was determined in ‘Gelin’, a* value in the ‘Harman’, b* and chroma values in the ‘Karpuz’ and hue angle in the ‘Rıza’ cultivar. The highest L* value was in the ‘Harman’, a* value was in the ‘Kuşak’, b*, chroma and hue angle values were in the ‘Gelin’ pear in terms of fruit flesh color. While ‘Macar’, ‘Harman’ and ‘Eşek’ cultivars had the highest juiciness value, ‘Macar’ and ‘Kuşak’ had the lowest taste and aroma. The highest taste and aroma values were in the ‘Kadın PArmak’ pear; the best visual quality was determined in the ‘Eşek’ cultivar. The highest titratable acid content was observed from the ‘Rıza’ (0.60%). In the study, it was found that the ‘Karpuz’ had higher pomological properties. In general, ‘Karpuz’, ‘Eşek’, and ‘Gelin’ pears exhibited better quality performances in the study. According to the results of the research, ‘Karpuz’, ‘Eşek’ and ‘Gelin’ local cultivars can be recommended for more detailed evoluations. In addition, the local cultivars used in the research can be used as genetic resources.

Genome assembly of wild loquat (Eriobotrya japonica) and resequencing provide new insights into the genomic evolution and fruit domestication in loquat.

Wild loquats (Eriobotrya japonica Lindl.) provide remarkable genetic resources for studying domestication and breeding improved varieties. Herein, we generate the first high-quality chromosome-level genome assembly of wild loquat, with 45 791 predicted protein-coding genes. Analysis of comparative genomics indicated that loquat shares a common ancestor with apple and pear, and a recent whole-genome duplication event occurred in loquat prior to its divergence. Genome resequencing showed that the loquat germplasms can be distinctly classified into wild and cultivated groups, and the commercial cultivars have experienced allelic admixture. Compared with cultivated loquats, the wild loquat genome showed very few selected genomic regions and had higher levels of genetic diversity. However, whole-genome scans of selective sweeps were mainly related to fruit quality, size, and flesh color during the domestication process. Large-scale transcriptome and metabolome analyses were further performed to identify differentially expressed genes (DEGs) and differentially accumulated metabolites (DAMs) in wild and cultivated loquats at various fruit development stages. Unlike those in wild loquat, the key DEGs and DAMs involved in carbohydrate metabolism, plant hormone signal transduction, flavonoid biosynthesis, and carotenoid biosynthesis were significantly regulated in cultivated loquats during fruit development. These high-quality reference genome, resequencing, and large-scale transcriptome/metabolome data provide valuable resources for elucidating fruit domestication and molecular breeding in loquat.

Papaya germplasm conservation through superior varieties assembly in Indonesia

Papaya (Carica papaya L.) is well adapted in tropical regions, including Indonesia, thus papaya genetic variability in this country is diverse. Indonesian papaya genetic variability is mainly observed on fruit quality characters, such as fruit size, flesh color, sweet taste, fruit texture, and flesh thickness. Papaya genetic resources conservation was conducted by employing them on papaya new superior variety improvement. Conventional papaya breeding was conducted through hybridization, selection, evaluation, and adaptation tests. Indonesian papaya hybridization and selection which are handled by the Indonesian Tropical Fruit Research Institute have been selected hybrids. The adaptation test of those selected genotypes has been carried out on several development regions. Overall, the papaya breeding activities have been delivered papaya varieties Merah Delima, Agri Solinda, Carvita Agrihorti, and a number of superior varieties candidate. The papaya superior varieties released with sweet taste, small to medium fruit size, thick flesh, high edible portion, high vitamin C content, red orange flesh color, and high productivity.

Phenotypic Variation and RAPD Polymorphism of Pisang Kepok Local Cultivars (Musa acuminata x Musa balbisiana, ABB, Saba Subgroup)

Pisang Kepok is a major local banana cultivar in Indonesia with high economic, social and cultural value. Particularly on the island of Java, there are several variations of Pisang Kepok recognised with their own local names, which makes difficulties in taxonomic identification and grouping. Morphological features are used in conventional banana cultivar classification, but they are deemed less precise due to their subjectivity, thus, it is supposed to be complemented with a molecular approach. This study aims to identify the phenotypic variation of Pisang Kepok local cultivars also their genetic polymorphism using Random Amplified Polymorphic DNA marker. Phenotypic variation was observed using 35 morphological characters. Six RAPD primers were used, i.e. OPA2, OPA3, OPA4, OPA11, OPA12, and OPA18. Clustering analysis, both phenotypic and genetic were performed using PAST v4.02. The morphological characterisation identified four variants of Pisang Kepok i.e. Kepok Abang, Kepok Putih, Kepok Manurun, and Kepok Australi; which all confirmed as ABB genome group. Phenotypic clustering showed that Pisang Kepok cultivars were separated into 3 clusters based on their local name, with a high similarity value of >90%. PCA biplot showed that the fruit flesh colour was the most important character contributed to the cultivar variation. RAPD marker also showed that each specimen was grouped according to its local name and source, with a similarity value of >80%. Both morphology and molecular (RAPD) markers resulted in the branching of Pisang Kepok which was closer to Pisang Klutuk than Pisang Barlin.

Keragaman Buah Pamelo Nambangan Hasil Induksi Sinar Gamma

Citrus has high commercial values both in local and global markets. Consumption of citrus as a fresh and functional fruit continues to increase along with the increase in population and the value of its benefits. The diversity of Indonesian local citrus with their specific value could be found in almost all regions. Nevertheless, the application of technology is necessary to improve the quality of local fruit performance and production quantity. Improvement of local fruit quality can be done through various methods, one of which is mutation by gamma ray induction. The aim of the study was to determine the fruit diversity of Nambangan Pummelo resulted from gamma ray induction. The research was conducted at the Experimental Field of Kraton Pasuruan and the Integrated Laboratory of Balitjestro in 2014. The results showed that the induced mutation contributed significantly to the increase in fruit diversity. Induced mutation has an effect on decreasing the number of seeds of the mutant fruit of Nambangan compared to control plant, increased the diversity of fruit flesh color, the level of bitterness and the shape of the fruit.

Selection of promising accessions of phalsa (Grewia asiatica L.) based on fruit-related traits.

Phalsa or falsa (Grewia asiatica L., family Malvaceae) is a promising, yet underutilized berry fruit of tropical regions. It contains a rich source of various bioactive compounds, such as anthocyanins, tannins, phenols, and flavonoids. In the present study, morphological and pomological diversity of 48 accessions of this species was evaluated to introduce superior selections. Considerable variability was detected among the accessions studied based on the characteristics recorded. Fruit shape exhibited the highest CV (69.66%), while seed length showed the lowest CV (7.98%). Fruit color showed strong diversity, including red, red-purple, purple-cream, purple, and dark purple. Fruit weight ranged from 0.29 to1.14 g, and fruit flesh thickness varied from 1.90 to 3.91 mm. Principal component analysis (PCA) showed that 82.64% of the variability observed was explained by the first 13 components. A dendrogram created using cluster analysis grouped the accessions into two major clusters. Based on the traits related to fruit quality, such as fruit weight, fruit color, fruit flesh color, and fruit taste, 14 accessions, including Talsar-6, Talsar-8, Ganjabad-31, Talsar-4, Ganjabad-18, Ganjabad-24, Talsar-5, Ganjabad-25, Ganjabad-30, Ganjabad-17, Talsar-7, Talsar-3, Talsar-2, and Talsar-1, were superior. It is recommended to use the best accessions selected in breeding programs.

Structural analysis of Actinidia arguta natural populations and preliminary application in association mapping of fruit traits

The fruit of Actinidia arguta are currently receiving much attention owing to their various colors in green or purple and fully edible smooth skin with unique shapes, taste appeal and rich nutritional value. A. arguta is now, after A. chinensis var. chinensis and A. chinensis var. deliciosa, the third most widely planted member of the Actinidia genus in commercial orchards. In order to improve our understanding of A. arguta and to plan future use of the germplasm for breeding elite cultivars, 189 accessions (including 14 cultivars) collected were analyzed with 200 simple sequence repeats (SSR) to explore their molecular diversity and population structure, and to identify elite alleles. The results showed all these markers used were polymorphic and generated 2496 allele loci with a polymorphism information content (PIC) value of 0.658. Through population structure analysis, the accessions have been divided into four subpopulations (K = 4), each subpopulation corresponding well with the distance-based clustering. Eleven traits were associated using MLM (mixed linear model) with markers. Marker-trait association analysis identified 43 significant associations involving the 35 SSRs for the 11 traits, including some important and interesting traits in breeding such as gender and fruit quality like flesh color. Through transient expression, LR71 discovered in this study is a marker significantly associated with fruit flesh color, belongs to a gene encoding an MYB transcription factor that regulates the accumulation of anthocyanins, and causes red pigmentation. This study revealed the extent of genetic diversity and the population structure of A. arguta germplasm collected. The trait-marker pairs obtained from association mapping have potential value in molecular marker-assisted breeding, and genomics studies with gene mapping. The relationships among the natural populations touched and the origin of the cultivars mainly used are discussed, all of these help us to further understand and analyze the natural evolution of A. arguta.

Efficient genetic transformation and CRISPR/Cas9-mediated genome editing of watermelon assisted by genes encoding developmental regulators.

Cucurbitaceae is an important family of flowering plants containing multiple species of important food plants, such as melons, cucumbers, squashes, and pumpkins. However, a highly efficient genetic transformation system has not been established for most of these species (Nanasato and Tabei, 2020). Watermelon (Citrullus lanatus), an economically important and globally cultivated fruit crop, is a model species for fruit quality research due to its rich diversity of fruit size, shape, flavor, aroma, texture, peel and flesh color, and nutritional composition (Guo et al., 2019). Through pan-genome sequencing, many candidate loci associated with fruit quality traits have been identified (Guo et al., 2019). However, few of these loci have been validated. The major barrier is the low transformation efficiency of the species, with only few successful cases of genetic transformation reported so far (Tian et al., 2017; Feng et al., 2021; Wang JF et al., 2021; Wang YP et al., 2021). For example, Tian et al. (2017) obtained only 16 transgenic lines from about 960 cotyledon fragments, yielding a transformation efficiency of 1.67%. Therefore, efficient genetic transformation could not only facilitate the functional genomic studies in watermelon as well as other horticultural species, but also speed up the transgenic and genome-editing breeding.

Gene prediction for leaf margin phenotype and fruit flesh color in pineapple (Ananas comosus) using haplotype-resolved genome sequencing.

Pineapple (Ananas comosus (L.) Merr.) is one of the most economically important tropical fruit species. The major aim of the breeding programs in several countries, including Japan, is quality improvement, mainly for the fresh market. ‘Yugafu’, a Japanese cultivar with distinctive pipe-type leaf margin phenotype and white flesh color, is popular for fresh consumption. Therefore, genome sequencing of ‘Yugafu’ is expected to assist pineapple breeding. Here, we developed a haplotype-resolved assembly for the heterozygous genome of ‘Yugafu’ using long-read sequencing technology and obtained a pair of 25 pseudomolecule sequences inherited from the parental accessions ‘Cream pineapple’ and ‘HI101’. The causative genes for leaf margin and fruit flesh color were identified. Fine mapping revealed a 162-kb region on CLG23 for the leaf margin phenotype. In this region, 20 kb of inverted repeat was specifically observed in the ‘Cream pineapple’ derived allele, and the WUSCHEL-related homeobox 3 (AcWOX3) gene was predicted as the key gene for leaf margin morphogenesis. Dominantly repressed AcWOX3 via RNAi was suggested to be the cause of the pipe-type leaf margin phenotype. Quantitative trait locus (QTL) analysis revealed that the terminal region of CLG08 contributed to white flesh and low carotenoid content. Carotenoid cleaved dioxygenase 4 (AcCCD4), a key gene for carotenoid degradation underlying this QTL, was predicted as the key gene for white flesh color through expression analysis. These findings could assist in modern pineapple breeding and facilitate marker-assisted selection for important traits.

Edible coating development to extend shelf life of mangoes (Mangivera indica L.)

Mango is one of the most favored tropical fruits which potentially as an export commodity in Indonesia. However, this fruit is easily damaged and has a short shelf life. One way to extend the shelf life of fruits is to use edible coatings. This study aimed to determine the effect of storage temperature and edible coatings on the shelf life of mangoes. Using 6.4% beeswax and a composite of 10% Arabic gum and 1% chitosan as edible coatings, these results were compared to control. Several parameters were used to evaluate the effectiveness of edible coatings, specifically weight loss, pH, fruit skin color, fruit flesh color, hardness, decay incidence (DI), and soluble solids concentration (SSC). Mangoes were stored in a variety of storage conditions, namely room temperature (26.5°C), showcase (10.2°C), and wine cooler (12.4°C). Experimental results indicated that applicating edible coatings and storing fruits at lower temperatures generally could reduce weight loss above 20% and DI by 85%, slowing changes in SSC, pH, and color of the fruits’ skin and flesh, as well as maintaining hardness. Moreover, 6.4% beeswax was more effective than the composite of 10% Arabic gum and 1% chitosan in extending the shelf life of mangoes.

Molecular Characterization of Some Apple Accessions Using DNA Markers Associated with Fruit Skin and Flesh Colour

Molecular Characterization of Some Apple Accessions Using DNA Markers Associated with Fruit Skin and Flesh Colour

An LTR retrotransposon in the promoter of a PsMYB10.2 gene associated with the regulation of fruit flesh color in Japanese plum.

Japanese plums exhibit wide diversity of fruit coloration. The red to black hues are caused by the accumulation of anthocyanins, while their absence results in yellow, orange or green fruits. In Prunus, MYB10 genes are determinants for anthocyanin accumulation. In peach, QTLs for red plant organ traits map in an LG3 region with three MYB10 copies (PpMYB10.1, PpMYB10.2 and PpMYB10.3). In Japanese plum the gene copy number in this region differs with respect to peach: there are at least three copies of PsMYB10.1, with the expression of one of them (PsMYB10.1a) correlating with fruit skin color. The objective of this study was to determine a possible role of LG3-PsMYB10 genes in the natural variability of the flesh color trait and to develop a molecular marker for marker-assisted selection (MAS). We explored the variability within the LG3-PsMYB10 region using long-range sequences obtained in previous studies through CRISPR-Cas9 enrichment sequencing. We found that the PsMYB10.2 gene was only expressed in red flesh fruits. Its role in promoting anthocyanin biosynthesis was validated by transient overexpression in Japanese plum fruits. The analysis of long-range sequences identified an LTR retrotransposon in the promoter of the expressed PsMYB10.2 gene that explained the trait in 93.1% of the 145 individuals analyzed. We hypothesize that the LTR retrotransposon may promote the PsMYB10.2 expression and activate the anthocyanin biosynthesis pathway. We propose for the first time the PsMYB10.2 gene as candidate for the flesh color natural variation in Japanese plum and provide a molecular marker for MAS.

Evaluation of new Turkish apricot genetic resources from the Irano-Caucasian eco-geographical group

This study presents 19 characters of 86 apricot cultivars and genotypes of the Irano- Caucasian eco-geographical group evaluated using principal component analysis. The high variability and differences among the apricot genotypes in terms of morphological, phenological and fruit quality traits were defined. The fruit size of the genotypes was generally very small (9.3 %) or small (43.0 %), the total rate of big and very big fruit genotypes was only 16.3%. The data showed that 90.1 % of the genotypes had yellow ground fruit colour, 88.4% had sweet kernel and 65% had firmness ?5 kg/cm2. About half of the apricot genotypes have 20% or high total soluble solids content. Most of the genotypes (67.3%) were harvested in mid-season and other genotypes (23.3%) were harvested early, while 4.7% of them were harvested very late, 3.5 % of the genotypes late. Only one genotype (1.2%) was harvested very early. The fruit size was highly correlated with fruit weight, pit weight and fruit flesh/pit rate. The same correlation was also observed between the fruit ground colour and fruit flesh colour. On the other hand, the total soluble solids were moderately correlated with fruit flesh firmness and seed taste. The results of the principal component analysis show that the 55% of the total variation is represented for the first three main components (22.9, 19.8, and 12.3%, respectively). The germplasm presented a large variation in the evaluated characters and most of the genotypes were found having high total soluble solids and low titratable acidity which would be beneficial for future breeding programs held to improve the related characters.

Identification of an Allelic Variant of the CsOr Gene Controlling Fruit Endocarp Color in Cucumber (Cucumis sativus L.) Using Genotyping-By-Sequencing (GBS) and Whole-Genome Sequencing.

The cucumber is a major vegetable crop around the world. Fruit flesh color is an important quality trait in cucumber and flesh color mainly depends on the relative content of β-carotene in the fruits. The β-carotene serves as a precursor of vitamin A, which has dietary benefits for human health. Cucumbers with orange flesh contain a higher amount of β-carotene than white fruit flesh. Therefore, development of orange-fleshed cucumber varieties is gaining attention for improved nutritional benefits. In this study, we performed genotyping-by-sequencing (GBS) based on genetic mapping and whole-genome sequencing to identify the orange endocarp color gene in the cucumber breeding line, CS-B. Genetic mapping, genetic sequencing, and genetic segregation analyses showed that a single recessive gene (CsaV3_6G040750) encodes a chaperone DnaJ protein (DnaJ) protein at the Cucumis sativus(CsOr) locus was responsible for the orange endocarp phenotype in the CS-B line. The Or gene harbored point mutations T13G and T17C in the first exon of the coding region, resulting in serine to alanine at position 13 and isoleucine to threonine at position 17, respectively. CS-B line displayed increased β-carotene content in the endocarp tissue, corresponding to elevated expression of CsOr gene at fruit developmental stages. Identifying novel missense mutations in the CsOr gene could provide new insights into the role of Or mechanism of action for orange fruit flesh in cucumber and serve as a valuable resource for developing β-carotene-rich cucumbers varieties with increased nutritional benefits.

FRUIT QUALITY OF NEW INTRODUCED PLUM CULTIVARS UNDER THE CONDITIONS OF BULGARIA

Prunus domestica L. is one of the most commonly grown fruit species in Bulgaria due to its high ecological adaptation and multiple ways of fruit marketing. Fruit quality is associated with attributes such as appearance, texture, taste and colour. Breeding and new cvs. introduction are in constant search for cultivars with better fruit quality that would answer the increasing consumer requirements. In 2013 the Romanian plum cvs. ‘Pitestean’, ‘Roman’, ‘Romanta’, ‘Carpatin’ and ‘Tita’ were introduced in Bulgaria and planted in a collection orchard at the Fruit Growing Institute, Plovdiv. The study was conducted in the period 2016-2021. It aimed to evaluate the fruit quality when the cultivars are grown under the agro-environmental conditions of the region. For obtaining this objective, fruit weight, fruit flesh firmness, TSS (°Brix), skin colour with and without wax bloom and fruit flesh colour were measured. For evaluating consumer acceptance, a sensory analysis was performed. ‘Roman’ had the largest fruits with an average fruit weight of 46.66 g and the highest TSS content – 18.2°Brix. There were significant differences in the colour parameters L*, a*, b*, Chroma and Hue between the cultivars and the wax bloom had a significant effect on colour parameters. All fruits were appreciated by the testing panel of consumers and their taste qualities were evaluated as good and very good.

A Review on the diversity of Melon

The species Cucumis melo L. (melon) is a polymorphic taxon encompassing many botanical and horticultural varieties. Melon fruits exhibit substantial variability in their form, shape, skin characters, flesh color, flesh thickness, sweetness, seed cavity, seed size, etc., which reflects in the market value of melon. This existing diversity in melon germplasm leads botanists to propose different classifications at the specific and infraspecific levels. The majority of classifications are based on morphological and molecular characteristics. Morphologic traits such as flower and fruit characteristics (sex expression, fruit size and shape, fruit skin color, pH, flesh color, taste, aroma, sugar composition, seed size, and shape) were used in the past centuries for melon diversity analysis. Later on, scientists correlate these phenotypic and biochemical traits (Total Soluble Solids, Ascorbic acid content, Titratable acidity, etc.) with genotypic variability by molecular tools. Molecular tools generally used for melon diversity analysis are RAPD, RFLP, AFLP, SSR markers, and Single Nucleotide Polymorphism (SNP). This article emphasizes the progress of studies in the species Cucumis melo L. and its varieties since 1753. Particular attention has been paid to collect data regarding different horticultural groups of the species, and a recent infraspecific classification of the species has also been outlined. Even though the modern molecular techniques provide new insight to melon classification still there is an existing disparity in these classifications, which could be visible to the scientific world.

Genome-wide association links candidate genes to fruit firmness, fruit flesh color, flowering time, and soluble solid content in apricot (Prunus armeniaca L.).

Apricots originated from China, Central Asia and the Near East and arrived in Anatolia, and particularly in their second homeland of Malatya province in Turkey. Apricots are outstanding summer fruits, with their beautiful attractive color, delicious sweet taste, aroma and high vitamin and mineral content. In the current study, a total of 259 apricots genotypes from different geographical origins in Turkey were used. Significant variations were detected in fruit firmness (FF), fruit flesh color (FFC), flowering time (FT), and soluble solid content (SSC). A total of 11,532 SNPs based on DArT were developed and used in the analyses of population structure and association mapping (AM). According to the STRUCTURE (v.2.2) analysis, the apricot genotypes were divided into three groups. The mixed linear model with Q and K matrixes were used to detect the associations between the SNPs and four traits. A total of 131 SNPs were associated with FF, FFC and SSC. No SNP marker was detected associated with FT. The results demonstrated that AM had high potential of revealing the markers associated with economically important traits in apricot. The SNPs identified in the study can be used in future breeding programs for marker-assisted selection in apricot.

Chromosome-Scale Genome and Comparative Transcriptomic Analysis Reveal Transcriptional Regulators of β-Carotene Biosynthesis in Mango.

Mango (2n = 2x = 40) is an important tropical/subtropical evergreen fruit tree grown worldwide and yields nutritionally rich and high-value fruits. Here, a high-quality mango genome (396 Mb, contig N50 = 1.03 Mb) was assembled using the cultivar “Irwin” from Florida, USA. A total of 97.19% of the sequences were anchored to 20 chromosomes, including 36,756 protein-coding genes. We compared the β-carotene content, in two different cultivars (“Irwin” and “Baixiangya”) and growth periods. The variation in β-carotene content mainly affected fruit flesh color. Additionally, transcriptome analysis identified genes related to β-carotene biosynthesis. MiPSY1 was proved to be a key gene regulating β-carotene biosynthesis. Weighted gene co-expression network analysis, dual luciferase, and yeast one-hybrid assays confirmed that transcription factors (TFs) MibZIP66 and MibHLH45 activate MiPSY1 transcription by directly binding to the CACGTG motif of the MiPSY1 promoter. However, the two TFs showed no significant synergistic effect on promoter activity. The results of the current study provide a genomic platform for studying the molecular basis of the flesh color of mango fruit.

Development of Genome-Wide Functional Markers Using Draft Genome Assembly of Guava (Psidium guajava L.) cv. Allahabad Safeda to Expedite Molecular Breeding

Guava (Psidium guajava L.), a rich source of nutrients, is an important tropical and subtropical fruit of the Myrtaceae family and exhibits magnificent diversity. Genetic diversity analysis is the first step toward the identification of parents for hybridization, genetic mapping, and molecular breeding in any crop species. A diversity analysis based on whole-genome functional markers increases the chances of identifying genetic associations with agronomically important traits. Therefore, here, we sequenced the genome of guava cv. Allahabad Safeda on an Illumina platform and generated a draft assembly of ~304 MB. The assembly of the Allahabad Safeda genome constituted >37.95% repeat sequences, gene prediction with RNA-seq data as evidence identified 14,115 genes, and BLAST n/r, Interproscan, PfamScan, BLAST2GO, and KEGG annotated 13,957 genes. A comparative protein transcript analysis of tree species revealed the close relatedness of guava with Eucalyptus. Comparative transcriptomics-based SSR/InDel/SNP-PCR ready genome-wide markers in greenish-yellow skinned and white fleshed-Allahabad Safeda to four contrasting cultivars viz apple-color-skinned and white-fleshed-Lalima, greenish-yellow-skinned and pink-fleshed-Punjab Pink, purple-black-skinned and purple-fleshed-Purple Local and widely used rootstock-Lucknow-49 were developed. The molecular markers developed here revealed a high level of individual heterozygosity within genotypes in 22 phenotypically diverse guava cultivars. Principal coordinate, STRUCTURE clustering, and neighbor-joining-based genetic diversity analysis identified distinct clusters associated with fruit skin and flesh color. The genome sequencing of guava, functional annotation, comparative transcriptomics-based genome-wide markers, and genetic diversity analysis will expand the knowledge of genomes of climacteric fruits, facilitating trait-based molecular breeding and diversifying the nutritional basket.