Fruit Shape Variation Research Articles

Identification of Key Genes of Fruit Shape Variation in Jujube with Integrating Elliptic Fourier Descriptors and Transcriptome.

Jujube (Ziziphus jujuba) exhibits a rich diversity in fruit shape, with natural occurrences of gourd-like, flattened, and other special shapes. Despite the ongoing research into fruit shape, studies integrating elliptical Fourier descriptors (EFDs) with both Short Time-series Expression Miner (STEM) and weighted gene co-expression network analysis (WGCNA) for gene discovery remain scarce. In this study, six cultivars of jujube fruits with distinct shapes were selected, and samples were collected from the fruit set period to the white mature stage across five time points for shape analysis and transcriptome studies. By combining EFDs with WGCNA and STEM, the study aimed to identify the critical periods and key genes involved in the formation of jujube fruit shape. The findings indicated that the D25 (25 days after flowering) is crucial for the development of jujube fruit shape. Moreover, ZjAGL80, ZjABI3, and eight other genes have been implicated to regulate the shape development of jujubes at different periods of fruit development, through seed development and fruit development pathway. In this research, EFDs were employed to precisely delineate the shape of jujube fruits. This approach, in conjunction with transcriptome, enhanced the precision of gene identification, and offered an innovative methodology for fruit shape analysis. This integration facilitates the advancement of research into the morphological characteristics of plant fruits, underpinning the development of a refined framework for the genetic underpinnings of fruit shape variation.

Respon Pertumbuhan dan Produksi Labu Madu (Cucurbita moschata) Keturunan Keempat (F4) Hidroponik Sistem NFT pada Konsentrasi Nutrisi AB Mix yang Berbeda

This study aims to obtain the best concentration of AB Mix nutrients for the growth and production of four (4) phenotypes of honey gourd (Cucurbita moschata) hydroponic NFT system, as well as determine the growth and production of four (4) phenotypes of honey gourd hydroponic NFT system at different AB Mix nutrient concentrations. This research was carried out at Greenhouse DnR Hydroponic Farm Housing Pondok Bedadung Indah Block AA.01. Sumbersari District, Jember Regency, East Java with an altitude of 70 meters above sea level from November 2022 to January 2023. This study was conducted using a Complete Randomized Design (RAL) factorial 3 x 4 with 3 repeats. The first factor is the concentration of AB Mix (N) nutrients consisting of three (3) levels, namely: 700 – 1400 ppm (N1), 900 - 1700 ppm (N2), 1100 - 2000 ppm (N3) and the second factor: phenotype (B) consists of four (4) phenotypes, namely: Flat round (B1), Round oval (B2), Long-necked (B3), Notched (B4). The parameters observed in this study include plant height, number of leaves, number of male flowers, number of female flowers, fruit diameter, fruit length, fruit weight, sweetness content. The observed data were analyzed with the F test to determine the effect of treatment. Different results were marked, followed by a level of 0.05. Using Duncan software test with SPSS 26 for windows. The results showed that AB Mix nutrition with a concentration of N3 (1100-2000) ppm resulted in the highest growth and production of F4 honey pumpkin on the parameters of plant height, number of leaves, number of male flowers, fruit diameter, fruit length, fruit weight, sweetness content, The influence of F4 honey pumpkin phenotype causes fruit shape diversity on the parameters of fruit diameter, fruit length, fruit weight. F4 seeds are heterozygous.

CsTRM5 regulates fruit shape via mediating cell division direction and cell expansion in cucumber.

Fruit shape and size are important appearance and yield traits in cucumber, but the underlying genes and their regulatory mechanisms remain poorly understood. Here we identified a mutant with spherical fruits from an Ethyl Methane Sulfonate (EMS)-mutagenized library, named the qiu mutant. Compared with the cylindrical fruit shape in 32X (wild type), the fruit shape in qiu was round due to reduced fruit length and increased fruit diameter. MutMap analysis narrowed the candidate gene in the 6.47MB range on Chr2, harboring the FS2.1 locus reported previously. A single-nucleotide polymorphism (SNP) (11359603) causing a truncated protein of CsaV3_2G013800, the homolog of tomato fruit shape gene SlTRM5, may underlie the fruit shape variation in the qiu mutant. Knockout of CsTRM5 by the CRISPR-Cas9 system confirmed that CsaV3_2G013800/CsTRM5 was the causal gene responsible for qiu. Sectioning analysis showed that the spherical fruit in qiu resulted mainly from increased and reduced cell division along the transverse and longitudinal directions, respectively. Meanwhile, the repressed cell expansion contributed to the decreased fruit length in qiu. Transcriptome profiling showed that the expression levels of cell-wall-related genes and abscisic acid (ABA) pathway genes were significantly upregulated in qiu. Hormone measurements indicated that ABA content was greatly increased in the qiu mutant. Exogenous ABA application reduced fruit elongation by inhibiting cell expansion in cucumber. Taken together, these data suggest that CsTRM5 regulates fruit shape by affecting cell division direction and cell expansion, and that ABA participates in the CsTRM5-mediated cell expansion during fruit elongation in cucumber.

Genome-Wide Identification of the SUN Gene Family in Melon (Cucumis melo) and Functional Characterization of Two CmSUN Genes in Regulating Fruit Shape Variation.

Melon (Cucumis melo) is an important economic crop cultivated worldwide. A unique SUN gene family plays a crucial role in regulating plant growth and fruit development, but many SUN family genes and their function have not been well-characterized in melon. In the present study, we performed genome-wide identification and bioinformatics analysis and identified 24 CmSUN family genes that contain integrated and conserved IQ67 domain in the melon genome. Transcriptome data analysis and qRT-PCR results showed that most CmSUNs are specifically enriched in melon reproductive organs, such as young flowers and ovaries. Through genetic transformation in melons, we found that overexpression of CmSUN23-24 and CmSUN25-26-27c led to an increased fruit shape index, suggesting that they act as essential regulators in melon fruit shape variation. Subcellular localization revealed that the CmSUN23-24 protein is located in the cytoplasmic membrane. A direct interaction between CmSUN23-24 and a Calmodulin protein CmCaM5 was found by yeast two-hybrid assay, which indicated their participation in the calcium signal transduction pathway in regulating plant growth. These findings revealed the molecular characteristics, expression profile, and functional pattern of the CmSUN genes, and may provide the theoretical basis for the genetic improvement of melon fruit breeding.

Biochemical, transcriptome and metabolome analysis of the pulp of Citrus sinensis (L.) Osbeck ‘Hong Jiang’ and its two variants reveal pathways regulating pulp taste, mastication, and color

BackgroundHong Jiang (HC), a grafted chimera of sweet orange (Citrus sinensis (L.) Osbeck), is prone to variations in fruit shape, taste, and pulp mastication. We studied the transcriptomes and metabolomes pf pulps of HC and its two variants (CB: fruits with changed pulp mastication, taste, and color and JB: fruits with changed pulp color and taste) to explore the related pathways. ResultsJB accumulated higher organic acids as compared to HC and CB. Flavonoid content was highest in HC followed by JB and CB. The soluble sugar content was lower, while cellulose content was higher in both JB and CB as compared to HC. We found 5,156 and 1,673 DEGs and 283 and 94 DAMs in HC vs JB and HC vs CB, respectively. The differential regulation of starch and sucrose metabolism, galactose metabolism, glycolysis/gluconeogenesis, fructose and mannose metabolism, and citrate cycle pathways could be associated with changes in sugar contents and tastes in JB and CB. Cell-wall polymer-related DEGs/DAMs were associated with the inferior mastication quality of JB and CB. Carotenoid biosynthesis possibly imparts yellowish and reddish pulp color in HC. Additional to this pathway, the anthocyanin biosynthesis led to the changes in JB and CB pulp color. ConclusionsThis combined methodological approach proved to be useful in delineating the large-scale changes in the transcripts and metabolites of variant fruits in a chimeric citrus variety. This study provides advanced and large-scale data on citrus taste, mastication, and pulp color.How to cite: Yang Z, Cao X, Zheng X, et al. Biochemical, transcriptome and metabolome analysis of the pulp of Citrus sinensis (L.) Osbeck ‘Hong Jiang’ and its two variants reveal pathways regulating pulp taste, mastication, and color. Electron J Biotechnol 2022;60. https://doi.org/10.1016/j.ejbt.2022.09.001.

Genetic legacy of ancient lands: Callitriche (Plantaginaceae) indicates Beringia and Paratethys Sea as diversification hotspots for aquatic vascular plants in Eurasia

The taxonomic status of endemic Callitriche taxa from western Beringia (C. subanceps) and the Lower Volga (C. fimbriata, C. transvolgensis) has been poorly studied. To investigate this question we compared endemic taxa with close Callitriche species. To achieve this goal we studied nuclear (ITS) and plastid (trnS-trnG, petL-psbE, trnH-psbA) genetic variation of almost 200 Callitriche samples and incorporated data on fruit shape variation and chromosome numbers. We found two genetically well-differentiated evolutionary lineages within C. heterophylla s.l. with rounded, wingless fruits, which diversification was likely associated with Beringia. One lineage occurs in western Beringia (known as C. subanceps), Greenland and northern North America, while another is confined to North America. Callitriche palustris, bearing winged, ovate fruits, is well-differentiated genetically from both C. heterophylla s.l. lineages. We refrain from any taxonomic decisions in C. heterophylla s.l. unless revision of full spectrum of diagnostic characters coupled with genetic studies with inclusion of abundant material from the both sides of the Bering Strait will be done. We demonstrated that Lower Volga endemics (C. fimbriata and C. transvolgensis) are separate species and their divergence might have been associated with dynamics of the Mediterranean, Black and Caspian seas. We point out importance of northern cryptic refugia (e.g. Lena River Delta) for cold-tolerant aquatic plants diversification.

BSA‐seq and quantitative trait locus mapping reveals a major effective QTL for carpel number in watermelon (Citrullus lanatus)

AbstractThe carpel number (CN) is related to fruit shape variation in watermelon and represents one of the most important agronomic traits. In this study, ZXG01553 (5‐CN type) and W1‐17 (3‐CN type) lines were used as parental material to construct F1, F2 and backcross populations for genetic inheritance analysis and QTL (quantitative trait locus) mapping. The F1 generation displayed the 3‐CN type and the frequency distribution of F2 individuals showed partial separation suggesting that the 3‐CN was dominant to 5‐CN trait and controlled by a major gene. Bulked‐segregant analysis (BSA‐seq) identified a chromosome segment related to the CN trait spanning 2.44 Mb on chromosome 7. Genetic linkage analysis using QTL mapping software narrowed this region to 244 Kb, and a major effective QTL was detected between markers Chr07‐30681552 and Chr07‐30923898. Twenty‐four genes were identified in the QTL region, in which Cla97C07G143260 annotated as Receptor‐like protein kinase 2 was the most likely candidate gene for the CN trait in watermelon. Our research provides new insights into the forward genetics of CN variation in cucurbit crops.

Genetic and Molecular Regulation Mechanisms in the Formation and Development of Vegetable Fruit Shape

Vegetable crops have a long history of cultivation worldwide and rich germplasm resources. With its continuous development and progress, molecular biology technology has been applied to various fields of vegetable crop research. Fruit is an important organ in vegetable crops, and fruit shape can affect the yield and commercialization of vegetables. In nature, fruits show differences in size and shape. Based on fruit shape diversity, the growth direction and coordination mechanism of fruits remain unclear. In this review, we discuss the latest research on fruit shape. In addition, we compare the current theories on the molecular mechanisms that regulate fruit growth, size, and shape in different vegetable families.

Pepper Fruit Elongation Is Controlled by Capsicum annuum Ovate Family Protein 20.

Fruit shape is one of the most important quality traits of pepper (Capsicum spp.) and is used as a major attribute for the classification of fruit types. Wide natural variation in fruit shape exists among the major cultivated species Capsicum annuum, allowing the identification of several QTLs controlling the trait. However, to date, no genes underlying fruit shape QTLs have been conclusively identified, nor has their function been verified in pepper. We constructed a mapping population from a cross of round- and elongated-fruited C. annuum parents and identified a single major QTL on chromosome 10, termed fs10, explaining 68 and 70% of the phenotypic variation for fruit shape index and for distal fruit end angle, respectively. The QTL was mapped in several generations and was localized to a 5 Mbp region containing the ortholog of SlOFP20 that suppresses fruit elongation in tomato. Virus-induced gene silencing of the pepper ortholog CaOFP20 resulted in increased fruit elongation on two independent backgrounds. Furthermore, CaOFP20 exhibited differential expression in fs10 near-isogenic lines, as well as in an association panel of elongated- and round-fruited accessions. A 42-bp deletion in the upstream region of CaOFP20 was most strongly associated with fruit shape variation within the locus. Histological observations in ovaries and fruit pericarps indicated that fs10 exerts its effect on fruit elongation by controlling cell expansion and replication. Our results indicate that CaOFP20 functions as a suppressor of fruit elongation in C. annuum and is the most likely candidate gene underlying fs10.

A cryptic variation in a member of the Ovate Family Proteins is underlying the melon fruit shape QTL fsqs8.1

Key messageThe gene underlying the melon fruit shape QTL fsqs8.1 is a member of the Ovate Family Proteins. Variation in fruit morphology is caused by changes in gene expression likely due to a cryptic structural variation in this locus.Melon cultivars have a wide range of fruit morphologies. Quantitative trait loci (QTL) have been identified underlying such diversity. This research focuses on the fruit shape QTL fsqs8.1, previously detected in a cross between the accession PI 124112 (CALC, producing elongated fruit) and the cultivar ‘Piel de Sapo’ (PS, producing oval fruit). The CALC fsqs8.1 allele induced round fruit shape, being responsible for the transgressive segregation for this trait observed in that population. In fact, the introgression line CALC8-1, carrying the fsqs8.1 locus from CALC into the PS genetic background, produced perfect round fruit. Following a map-based cloning approach, we found that the gene underlying fsqs8.1 is a member of the Ovate Family Proteins (OFP), CmOFP13, likely a homologue of AtOFP1 and SlOFP20 from Arabidopsis thaliana and tomato, respectively. The induction of the round shape was due to the higher expression of the CALC allele at the early ovary development stage. The fsqs8.1 locus showed an important structural variation, being CmOFP13 surrounded by two deletions in the CALC genome. The deletions are present at very low frequency in melon germplasm. Deletions and single nucleotide polymorphisms in the fsqs8.1 locus could not be not associated with variation in fruit shape among different melon accessions, what indicates that other genetic factors should be involved to induce the CALC fsqs8.1 allele effects. Therefore, fsqs8.1 is an example of a cryptic variation that alters gene expression, likely due to structural variation, resulting in phenotypic changes in melon fruit morphology.

Development and validation of the OVATE gene-based functional marker to assist fruit shape selection in tomato.

The online version contains supplementary material available at 10.1007/s13205-021-03029-7.

Long-read genome assembly and genetic architecture of fruit shape in the bottle gourd.

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.

Exploration into natural variation for genes associated with fruit shape and size among Capsicum chinense collections

Phenotype diversity within cultivated Capsicum chinense is particularly evident for fruit shape and size. We used this diversity in C. chinense to further unravel the genetic mechanisms underlying fruit shape variation in pepper and related Solanaceous species. We identified candidate genes for C. chinense fruit shape, explored their contribution to population structure, and characterized their potential function in pepper fruit shape. Using genotyping by sequencing, we identified 43,081 single nucleotide polymorphisms (SNPs) from diverse collections of C. chinense. Principal component, neighbor-joining tree, and population structure analyses resolved 3 phylogenetically robust clusters associated with fruit shapes. Genome-wide association study (GWAS) was used to identify associated genomic regions with various fruit shape traits obtained from image analysis with Tomato Analyzer software. In our GWAS, we selected 12 SNPs associated with locule number trait and 8 SNP markers associated with other fruit shape traits such as perimeter, area, obovoid, ellipsoid and morphometrics (5y, 6y and 7y). The SNPs in CLAVATA1, WD-40, Auxin receptor, AAA type ATPase family protein, and RNA polymerase III genes were the major markers identified for fruit locule number from our GWAS results. Furthermore, we found SNPs in tetratricopeptide-repeat thioredoxin-like 3, enhancer of ABA co-receptor 1, subunit of exocyst complex 8 and pleiotropic drug resistance proteins associated with various fruit shape traits. CLAVATA1, WD-40 and Auxin receptor genes are known genes that affect tomato fruit shape. In this study, we used Arabidopsis thaliana T-DNA insertion knockout mutants and expression profiles for functional characterization of newly identified genes and to understand their role in fruit shape.

Markers for selection of three alleles of ClSUN25-26-27a (Cla011257) associated with fruit shape in watermelon

Fruit shape is an economically important trait in many horticultural crops. The genes and mechanisms underlying fruit shape variation are poorly understood in watermelon. A deletion (DEL) in ClSUN25-26-27a (Cla011257), a member of the SUN gene family, has been shown to be associated with elongated fruit. In the current study, we sequenced ClSUN25-26-27a in three watermelon cultivars with different fruit shape indices (FSIs). A novel allele containing a non-synonymous point mutation in exon 3 was identified in Klondike Black Seeded. KASP assays (ClSUN-1 and ClSUN-2) were developed to distinguish three ClSUN25-26-27a alleles (WT, KBS, and DEL), and their effects on ovary and fruit shape traits were determined in a cultivar panel and segregating populations. The different alleles showed a significant association with ovary and fruit length and shape as well as the angles of the distal and proximal ends. These effects were primarily pre-anthesis. The KASP assays can serve as tools for marker-assisted selection (MAS) of fruit length and shape in watermelon. This study highlights the allelic variation in ClSUN25-26-27a and its association with fruit shape in watermelon.

Evolution of Lineage-Specific Gene Networks Underlying the Considerable Fruit Shape Diversity in Persimmon.

The shapes of plant organs reflect the evolution of each lineage and have been diversified according to lineage-specific adaptations to environment. Research on the molecular pathways responsible for organ shapes has traditionally been focused mainly on leaves or flowers. Thus, little is known about the pathways controlling fruit shapes, despite their diversity in some plant species. In this study, we analyzed oriental persimmon (Diospyros kaki), which exhibits considerable diversity in fruit shapes among cultivars, to elucidate the underlying molecular mechanism using transcriptomic data and quantitative evaluation. First, to filter the candidate genes associated with persimmon fruit shapes, the whole gene expression patterns obtained using mRNA-Seq analysis from 100 individuals, including a segregated population and various cultivars, were assessed to detect correlations with principal component scores for fruit shapes characterized with elliptic Fourier descriptors. Next, a gene co-expression network analysis with weighted gene co-expression network analysis (WGCNA) package revealed that class 1 KNOX family genes and SEEDSTICK function as integrators along with some phytohormone-related genes, to regulate the fruit shape diversity. On the other hand, the OVATE family genes also contribute to fruit shape diversity, of which pathway would be potentially shared with other plant species. Evolutionary aspects suggest that acquisition of a high lineage-specific and variable expression of class 1 KNOX gene, knotted-like homeobox of Arabidopsis thaliana 1 (KNAT1), in young fruit is important for establishing the persimmon-specific mechanism that determines fruit shape diversity.

A common genetic mechanism underlies morphological diversity in fruits and other plant organs

Shapes of edible plant organs vary dramatically among and within crop plants. To explain and ultimately employ this variation towards crop improvement, we determined the genetic, molecular and cellular bases of fruit shape diversity in tomato. Through positional cloning, protein interaction studies, and genome editing, we report that OVATE Family Proteins and TONNEAU1 Recruiting Motif proteins regulate cell division patterns in ovary development to alter final fruit shape. The physical interactions between the members of these two families are necessary for dynamic relocalization of the protein complexes to different cellular compartments when expressed in tobacco leaf cells. Together with data from other domesticated crops and model plant species, the protein interaction studies provide possible mechanistic insights into the regulation of morphological variation in plants and a framework that may apply to organ growth in all plant species.

Genetic Diversity between Pumpkin Accessions Growing in the Northern Border Region in Saudi Arabia Based on Biochemical and Molecular Parameters

THE GENETIC variation and relationships among 16 pumpkin accessions of Cucurbita moschata & Cucurbita maxima were assessed based on variation in fruit shape, skin color, flesh and size of fruits. Polyacrylamide gel electrophoresis of seed protein and molecular markers revealed by SCoT and ISSR techniques. The SDS-PAGE electropherogram showed 12 bands; two (75 and 145 kDa) were found in accessions (1-8) and one (85 kDa) was found in accessions 9-16. Other three bands were unique to accessions 1, 2 & 11. Five ISSR primers produced 79 markers ranging in molecular size from 130 to 2140 bp. Six SCoT primers produced 173 markers ranging from 135 to 2660 bp. The ISSR polymorphism among the examined accessions was 100% in the case of primers 49A, 44 B and HB-12, and was 92% for primer HB-15. Similarly, 100% polymorphism was scored for the primers SCoT8, SCoT11, SCoT12 and SCoT14. The lowest polymorphism was 93.94% in case of primer SCoT1. Our data based on protein, RAPD and ISSR data using the SYSTAT version 7.0 program clearly distinguished accessions from each other.

Quantitative Trait Loci Controlling Fruit Size and Other Horticultural Traits in Bell Pepper (Capsicum annuum).

Bell pepper ( L.) is a group of fruit vegetables that has large variation in fruit shape, fruit size, and horticultural traits. Using unadapted sources of germplasm to bring in novel alleles while maintaining favorable quality and horticultural traits is challenging for breeding in pepper. A genetic map with 318 loci from genotype-by-sequencing (GBS) and single nucleotide polymorphism assays was generated from a recombinant inbred line population derived from a cultivated bell-type 'Maor' and a landrace highly resistant to , 'Criollo de Morelos-334'. Forty-nine quantitative trait loci (QTLs) were detected for fruit, leaf, and horticultural traits with the scantwo permutation and stepwiseqtl methods from R/qtl. With the availability of a pepper reference genome and GBS data, candidate genes for pepper organ size and other horticultural traits were predicted. , , and genes were candidate genes for controlling organ sizes on chromosome 1, 2, and 3, respectively. Two candidate genes controlling trichome formation in pepper are located at chromosome 10: and . The locus on chromosome 10, which encodes a member of the R2R3 MYB-domain family of proteins, has a function in anthocyanin accumulation. These QTL results and the candidate genes for each trait emphasize the genetic basis of the important traits for breeding with unadapted parents in bell pepper.

Diversity of Treegourd (Crescentia cujete) Suggests Introduction and Prehistoric Dispersal Routes into Amazonia

The use and dispersal of domesticated plants may reflect patterns of early human diffusion of technologies and lifestyles. Treegourd (Crescentia cujete) has fruits with ancient utilitarian and symbolic value in the Neotropics. We assessed diversity based on chloroplast (SNPs), nuclear (SSR) markers, and fruit shapes of cultivated treegourds and wild relatives across Amazonia and Mesoamerica in order to discuss hypothesis of dispersal routes and diversification of fruits along its distribution. The haplotype network showed three distinct groups: Crescentia amazonica, wild Mesoamerican C. cujete, and cultivated C. cujete from Brazilian Amazonia and Mexico. Mexico and Brazil shared two haplotypes, with slightly different distributions in Amazonia. The most divergent haplotype is well-represented in Eastern Amazonia. Nuclear differentiation between Mesoamerican wild and cultivated C. cujete is relatively low (FST = 0.35), compared with Amazonian cultivated (FST = 0.45–0.61). Differentiation is also higher between wild C. amazonica and cultivated C. cujete (FST = 0.57), but modest within cultivated C. cujete from Amazonia and Mexico (FST = 0.04), with higher genetic similarity in northwestern Amazonia. Mexico and Amazonia showed similar chloroplast nucleotide diversity (4.66 × 10−2 and 5.31 × 10−2 , respectively), although sample sizes are very different. Except in Northwestern and Eastern Amazonia, we found ample genetic homogeneity of cultivated C. cujete across Amazonia, but highest morphological diversity in the Northwest, with fruit shapes that are absent in Mexico. We conclude that treegourds introduced into the Amazon Basin and Mexico share a common ancestry with a currently unknown origin. The patterns of genetic diversity across Amazonia allow two hypotheses of the routes of introduction: a northwestern introduction into the Negro and Solimoes Rivers, and an eastern introduction from the coastal Guianas into the Amazonas River. The dispersal into Amazonia followed previously proposed routes of human and plant migrations. The contrasting fruit shape diversity suggests different utilitarian demands and cultural preferences for treegourd fruits between Mexico and Amazonia.

Quantitative characterization of fruit shape and its differentiation pattern in diverse persimmon (Diospyros kaki) cultivars

Abstract There is considerable diversity in fruit shapes among persimmon (Diospyros kaki) cultivars. Although fruit shape is one of the most important traits affecting the commercial quality of fruits, quantitatively characterizing fruit shape features remains difficult. The objective of this study was to develop a reliable method for quantitatively analyzing persimmon fruit shapes, and to clarify the fruit development patterns as well as their relationships to the shapes of other organs across cultivars. Using 153 persimmon cultivars and two wild Diospyros relatives, we evaluated two-dimensional pictures of longitudinal and transverse fruit sections with elliptical Fourier descriptors (EFDs) and the SHAPE program. Principal component analysis (PCA) using each EFD generated representative vectors, which elucidated the fruit shape diversity among the cultivars. Additionally, a PCA of the EFDs quantified two major components of the variability in the shapes of longitudinal fruit sections, namely the ratio of length to diameter and the fruit apex shape. Seasonal characterizations of the first principal component revealed the fruit shape development patterns. The fundamental shapes in the longitudinal direction were coordinately determined during the early developmental stages across cultivars. Furthermore, a quantitative characterization of persimmon fruit, seed, and leaf shapes unveiled correlations between these traits. The data presented herein indicate that combining EFDs and PCA enables the quantitative analysis of persimmon organ shapes, which may be related to various quantitative indices.