Fruit Morphology Research Articles

Discovery of Buxaceae in Acre State, southwestern Amazon: First record of this ancient plant family in Brazil

The first record of Buxaceae for the flora of Brazil was made during fieldwork at the Rio Acre Ecological Station, Acre State, on the border between Brazil and Peru. This study describes the first record of Styloceras brokawii in the region and distinguishes it from other species within the genus based primarily on leaf and fruit morphology.

The miR319-based repression of SlTCP2/LANCEOLATE activity is required for regulating tomato fruit shape.

Fruit morphogenesis is determined by the coordination of cell division and expansion, which are fundamental processes required for the development of all plant organs. Here, we show that the regulation of TEOSINTE BRANCHED1/CYCLOIDEA/PCF (TCP) LANCEOLATE (TCP2/LA) by miR319 is crucial for tomato fruit morphology. The loss of miR319 regulation in the semi-dominant La mutant led to a premature SlTCP2/LA expression during gynoecium patterning, which results in modified cell division during carpel development. As a consequence, La mutants exhibited elongated ovary and fruit shape, and a reduced number of ovules and seeds. Elongated fruit shape in La may be partially due to the SlTCP2/LA-mediated repression of OVATE activity in young floral buds. Further analysis showed that the de-repression of SlTCP2/LA decreases auxin responses in young floral buds by directly repressing SlYUCCA4 expression, but SlTCP2/LA also acts in parallel with ENTIRE (E) to orchestrate fruit morphology and seed production. Our study defines a novel miRNA-based molecular link between the domestication-associated OVATE gene and auxin responses. Given the striking variation in fruit morphology among members of the Solanaceae family, fine-tuning regulation of gene expression by miRNA coupled with modulation of auxin dynamics may be a common driver in the evolution of fruit shape diversity.

Exploring Genomic Regions Associated with Fruit Traits in Pepper: Insights from Multiple GWAS Models.

This study utilized 303 pepper accessions from diverse Capsicum species to explore fruit traits, including length, width, wall thickness, and weight. Descriptive statistics revealed a mean fruit length of 66.19 mm, width of 23.48 mm, wall thickness of 1.89 mm, and weight of 15.29 g, with significant variability, particularly in fruit weight. Correlation analysis demonstrated strong positive relationships between fruit width, weight, and fruit wall thickness (r = 0.89 and r = 0.86, respectively), while fruit length showed weaker correlations with these traits. Analysis of fruit positions revealed that the majority of accessions had a pendent fruit position (156), followed by erect (85) and intermediate (8). In terms of fruit shape, triangular and narrow triangular shapes were the most common, observed in 102 and 98 accessions, respectively. Genome-wide association studies (GWAS) identified significant single nucleotide polymorphisms (SNPs) associated with fruit traits across four models (Blink, FarmCPU, MLM, MLMM). The number of significantly associated SNPs were as follows: fruit length (89), fruit width (55), fruit weight (63), fruit wall thickness (48), fruit shape (151), and fruit position (51). Several genes were also identified where the SNPs are located or adjacent to, providing candidate genes for further exploration of the genetic basis of fruit morphology. Notably, genes such as E3 ubiquitin-protein ligase RGLG1 (associated with fruit width), Homeobox-leucine zipper protein HDG11 (involved in fruit width), Auxin response factor 23 (linked to fruit shape), and ATP-dependent zinc metalloprotease FtsH (related to fruit weight) were identified. These findings enhance our understanding of the genetic basis of fruit morphology in Capsicum, offering valuable insights for breeding and agricultural practices.

Genetic basis of melon fruit morphology and domestication

Genetic basis of melon fruit morphology and domestication

MICROMORPHOLOGICAL STUDIES (ACHENE / CYPSELA) ON SELECTED ASTERACEAE TAXA NATIVE TO TURKIYE

With this study fruit width-length measurements, weights and surface morphologies of some taxa belonging to Asteraceae family distributed in Türkiye were studied. The aim of the study was to reveal the fruit morphological characteristics and differences between the taxa of Tragopogon buphthalmoides, Dittrichia viscosa, Dittrichia graveolens, Tripleurospermum caucasicum, Kemulariella caucasica, Leontodon hispidus subsp. hispidus, Jurinea consanguinea and Jurinea moschus. Widths and lengths of the fruits were measured with Leica EZ4 microscope and digital caliper. Fruit weights were weighted out with Dikomsan precision scales. The stereomicroscope to determine the morphological characteristics of the fruits was also used. Scanning Electron Microscopy (SEM) in USKIM (Center for University and Industry Collaboration) was used to determine the surface morphology of the fruits. The smallest fruits were determined in Dittrichia graveolens (0.40 mm wide and 1.23 mm long), while the largest fruits were determined in Tragopogon buphthalmoides (25.88 mm long and 1.62 mm wide). The heaviest fruits were measured in Jurinea consanguinea (0.0065 gr) and the slightest fruits in Dittrichia graveolens (0.000062 gr) taxa.

Genetic Regulation of Fruit Shape in Horticultural Crops: A Review

The shape of fruits is a critical trait affecting the commercial value and consumer acceptance of horticultural crops. Genetic regulation of fruit shape involves complex interactions among multiple genes and environmental factors. This review summarizes recent advances in understanding the genetic mechanisms controlling fruit shape in several key horticultural crops, including tomato, pepper, cucumber, peach, and grape. We present the identification and characterization of genes and quantitative trait loci (QTLs) that influence fruit shape, focusing on the roles of genes such as OVATE, SUN, FAS, LC, ENO, GLOBE, CsSUN, CsFUL1, CsCRC, PpCAD1, PpOFP1, and VvSUN. This review highlights the importance of hormonal pathways, particularly those involving synthesis and concentration of cytokinins and brassinosteroids in shaping fruit morphology, and explores how these genes interact and form regulatory networks that collectively determine the final fruit shape. This knowledge provides a foundation for developing strategies to improve fruit quality and yield through genetic modification and breeding programs.

Impacts of land use and abiotic factors on fruit, seed, and leaf morphology of the desert date Balanites aegyptiaca in Benin: Implications for management

Preserving intraspecific phenotypic variation within socio-economically important but declining species is fundamental in the current context of rapid change in land use and environmental conditions. Balanites aegyptiaca (L.) Delile is a valuable seed oil tree species native to the arid and semi-arid regions of Africa. Notable morphological variations within the species are recognized by local communities, who often select trees with preferred traits for preservation in croplands. This study compared phenotypic variation in B. aegyptiaca based on sixteen phenotypic traits of fruits, seeds, and leaflets between trees in a strictly protected area and those in croplands. Furthermore, the relative role of land use, soil characteristics, bioclimatic variables, elevation, and slope in the observed variation was analysed. Student t-test, principal component analysis, redundancy analysis, and variance partitioning were used for data analysis in R software. Results showed that, after accounting for tree variation, significant differences were observed in only two traits: seed ratio, and leaflet dry weight, with mean values in cropland being 1.470 (higher), and 0.943 (lower) times that of wild trees, respectively. Furthermore, principal component analysis showed great overlap between ellipses of cropland and wild trees. The variance partitioning analysis showed that bioclimatic variables explained 18 % of the total variation followed by soil characteristics (11 %), and land use (9 %). These findings collectively suggest weak impacts of croplands and a lack of domestication syndrome in B. aegyptiaca in Benin, potentially due to persisting gene flow between wild and cropland trees, inadvertent species management, or low intensity of selection pressures. Future studies should explore organoleptic properties, physico-chemical characteristics of the pulp and seed oil and discern the extent to which observed differences are attributable to genetic factors and biotic factors (pest attacks, plant-plant interactions, etc.).

Does long-term radiation exposure in Chornobyl impact the reproductive structures of Nuphar lutea (Linné) Smith?

The 1986 Chornobyl Nuclear Power Plant accident caused radioactive contamination of water bodies within the Pripyat River floodplain, resulting in the accumulation of radionuclides by macrophytes, which are fundamental species in water ecosystems. Yellow water lily Nuphar lutea (L.) Smith., a macrophyte playing a significant role in the formation of vegetation cover in aquatic ecosystems, is commonly considered as a bioindicator of water pollution. In this study, we investigate the potential of N. lutea as an indicator of radionuclide contamination in water bodies, particularly through changes in its reproductive structures, such as pollen viability, morphology of pollen grains, seeds, and fruits. Our findings reveal that pollen viability remains stable at total absorbed dose rates below 14.4 μGy/h, with only 1–4% of sterile grains. However, beyond this threshold the percentage of sterile grains increases nearly fivefold, pointing to high internal plant exposure to 90Sr. A similar trend was observed in the allometry and size of pollen grains, where small and flattened grains are formed in the reservoir with the highest external radiation dose rate (≥14.4 μGy/h). On the other hand, while morphometric parameters of fruits are influenced by radiation, their variation appears to be the result of a combination of physicochemical factors and the trophic status of a water body. Our research highlights the adverse impact of long-term radiation exposure on the male reproductive system of N. lutea and shows the potential of using the pollen grains sterility as an indicators of heavily radionuclide-contaminated water bodies. Additionally, we observed gradual changes in a pollen allometric length-to-width coefficient as the radiation dose level increases.

Dynamic Analysis of the Fruit Sugar-Acid Profile in a Fresh-Sweet Mutant and Wild Type in 'Shatangju' (Citrus reticulata cv.).

Citrate is a major determinant of fruit flavor quality. Currently, citrus species and/or varieties with significant alterations in citrate level have greatly advanced the molecular basis of citrate accumulation in fruit. However, in-depth dissections of the molecular mechanism specific to citrate accumulation are still limited due to the lack of mutants, especially within one single variety. In this study, a fresh-sweet 'Shatangju' mutant (Citrus reticulata cv.) was obtained during a survey of citrus resources in Guangdong, China, and the phenotype, fruit morphology, and primary flavor profiles were comparatively analyzed. Unlike the wild-type 'Shatangju' (WT), the mutant (MT) material exhibited a dwarfed and multi-branched tree shape, delayed flowering and fruit ripening at maturity, a prolonged fruit tree-retention time, and a decreased single fruit weight at maturity. Dynamic measurement of the metabolite levels further suggested that the contents and fluctuation patterns of vitamin C, malate, quinate, and oxalate showed no obvious difference between MT and MT fruits, while the citrate level in MT fruits significantly decreased over various developmental stages, ranging from 0.356 to 1.91 mg g-1 FW. In addition, the accumulation patterns of the major soluble sugars (sucrose, fructose, and glucose), as well as the sugar/acid ratio, were also altered in MT fruits during development. Taken together, this study provides a novel acid-free 'Shatangju' mutant, which can serve as a powerful tool for the research of fruit flavor quality, especially for the comprehensive understanding of the molecular mechanism of citrate accumulation in fruits.

Developmental Morphology, Physiology, and Molecular Basis of the Pentagram Fruit of Averrhoa carambola.

Averrhoa carambola, a key tropical and subtropical economic tree in the Oxalidaceae family, is distinguished by its unique pentagram-shaped fruit. This study investigates the developmental processes shaping the polarity of A. carambola fruit and their underlying hormonal and genetic mechanisms. By analyzing the Y1, Y2, and Y3 developmental stages-defined by the fruit diameters of 3-4 mm, 4-6 mm, and 6-12 mm, respectively-we observed that both cell number and cell size contribute to fruit development. Our findings suggest that the characteristic pentagram shape is established before flowering and is maintained throughout development. A hormonal analysis revealed that indole-3-acetic acid (IAA) and abscisic acid (ABA) show differential distribution between the convex and concave regions of the fruit across the developmental stages, with IAA playing a crucial role in polar auxin transport and shaping fruit morphology. A transcriptomic analysis identified several key genes, including AcaGH3.8, AcaIAA20, AcaYAB2, AcaXTH6, AcaYAB3, and AcaEXP13, which potentially regulate fruit polarity and growth. This study advances our comprehension of the molecular mechanisms governing fruit shape, offering insights for improving fruit quality through targeted breeding strategies.

A Multi-Fruit Recognition Method for a Fruit-Harvesting Robot Using MSA-Net and Hough Transform Elliptical Detection Compensation

In the context of agricultural modernization and intelligentization, automated fruit recognition is of significance for improving harvest efficiency and reducing labor costs. The variety of fruits commonly planted in orchards and the fluctuations in market prices require farmers to adjust the types of crops they plant flexibly. However, the differences in size, shape, and color among different types of fruits make fruit recognition quite challenging. If each type of fruit requires a separate visual model, it becomes time-consuming and labor intensive to train and deploy these models, as well as increasing system complexity and maintenance costs. Therefore, developing a general visual model capable of recognizing multiple types of fruits has great application potential. Existing multi-fruit recognition methods mainly include traditional image processing techniques and deep learning models. Traditional methods perform poorly in dealing with complex backgrounds and diverse fruit morphologies, while current deep learning models may struggle to effectively capture and recognize targets of different scales. To address these challenges, this paper proposes a general fruit recognition model based on the Multi-Scale Attention Network (MSA-Net) and a Hough Transform localization compensation mechanism. By generating multi-scale feature maps through a multi-scale attention mechanism, the model enhances feature learning for fruits of different sizes. In addition, the Hough Transform ellipse detection compensation mechanism uses the shape features of fruits and combines them with MSA-Net recognition results to correct the initial positioning of spherical fruits and improve positioning accuracy. Experimental results show that the MSA-Net model achieves a precision of 97.56, a recall of 92.21, and an mAP@0.5 of 94.81 on a comprehensive dataset containing blueberries, lychees, strawberries, and tomatoes, demonstrating the ability to accurately recognize multiple types of fruits. Moreover, the introduction of the Hough Transform mechanism reduces the average localization error by 8.8 pixels and 3.5 pixels for fruit images at different distances, effectively improving the accuracy of fruit localization.

Changes in the fruits and seeds morphometric, germination, phytochemicals content, and antioxidant capacity in seed ripening of Echinocereus stramineus

Within the cacti family, most studies have focused on the physicochemical characterization of the stems, fruits, and seeds from Mammillaria, Opuntia, Hylocereus, and Stenocereus genera. However, few information is focused on the morphological and physicochemical characterization of the stems, fruits, and seeds of other genera widely distributed in the arid and semiarid zones of the Chihuahuan desert, such as the genus Echinocereus. The objective of this study was to analyze the fruit morphology, morphometry, germination process, and phytochemical content in four stages of seed in fruit ripening from E. stramineus. Morphometric parameters were measured by picking ten fruits and sixty seeds for each ripening stage. The characterization of the germination process included the germination percentage, mean germination time, germination speed, and mean germination speed which were computed 21 days after germination. The quantification of total phenols, flavonoids, tannins, reducing sugars, protein, and antioxidant activity of seeds was determined using colorimetric approaches under basal conditions. The morphometric results revealed a negative correlation between the fruit ripening stage and total mass (r= -0.980, p = 0.020), shell mass (r= -0.986, p = 0.014), pulp mass (r = -0.979, p = 0.021), fruit length (r = -0.978, p = 0.022), fruit width (r = -0.968, p = 0.032) and fruit area (r = -0.960, p = 0.04). The germination characterization process showed a negative association between the fruit ripening stage and the seed germination percentage (r = -0.979, p = 0.021) and between the seed mean germination time and the mean germination speed (r= -0.986, p = 0.014). The content of flavonoids, reducing sugars, proteins, and antioxidant capacity showed significant differences among the four stages of fruit ripening; however, no association was found between seed phytochemical content and the ripening stage. This study provides the first data on seed phytochemicals and information on the germination process of E. stramineus seeds.

Comparative fruit morphology of nine Psittacanthus Mart. (Santalales: Loranthaceae) mistletoe species occurring in Mexico

The genus Psittacanthus is distributed from Mexico to Argentina and contains c. 110 species. The large, lipid-rich, one-seeded fruits of Psittacanthus species frequently depend on frugivorous birds for seed dispersal; however, fruit morphology of Psittacanthus (Loranthaceae) mistletoes remain poorly studied. In this study we describe the fruit morphology of nine Psittacanthus species. Fruits were collected from the study sites in which mistletoe plants were inhabiting contrasting habitats and host tree species. The morphological characteristics of fruits by species were described and compared with the use of inclusion and staining techniques and light microscopy. Our results show that fruit size varies among species, with P. macrantherus having the largest fruits. Most fruits have an ellipsoid to ovoid shape, color of fruits transits from green when immature to red or purple before ripening to blackish or purplish black, with color variations observed in different species, and the cupular pedicel length varying among species. Fruit sections indicate the following parts: exocarp, viscin layer, seed coat and a dicotylar to polycotylar embryo, with P. schiedeanus having the highest cotyledon count. No endosperm is present in the studied species. Our results provide valuable information for further species comparisons regarding the lack of endosperm and polycotylar embryo. Additionally, interspecific variation in cotyledon number and seed coat highlights distinct processes, including the potential effects of environmental differences.

Morphology and ITS sequences provide insights into the phylogeny of Tongoloa (Apiaceae) from China

BackgroundTongoloa is a genus comprising approximately 20 species, primarily distributed in the mountainous regions of southwest China. The insufficiency of specimen materials and morphological similarities among species render it a taxonomically challenging genus within the Apiaceae family. To elucidate the phylogenetic relationships and taxonomy of Chinese Tongoloa, this study utilized a total of 115 nrITS sequences, including 47 recently obtained sequences, for phylogenetic reconstruction.ResultsPhylogenetic relationships reconstructed from ITS sequences indicate that the East Asia Clade and the Komarovia Clade are sister groups, and Tongoloa belongs to the East Asia Clade. Species of Tongoloa are subdivided into 3 distinct groups, all sharing similar fruit morphologies and are clearly differentiated from related taxa. Several Tongoloa-like members classified under other genera are interpreted to be closely related to Tongoloa. Morphological and molecular data indicate that Tongoloa, Sinolimprichtia subclade and Chinese Trachydium subclade are separate yet genetically contiguous taxa. It is confirmed that Tongoloa zhongdianensis belongs to the Hymenidium Clade, while Sinocarum is classified within the Acronema Clade. Two new taxa are found in the Hengduan Mountains.ConclusionTongoloa is a genus within the East Asia Clade of Apiaceae, and the phylogeny reconstructed based on ITS sequences divides it into 3 main groups. By integrating fruit morphology and molecular phylogenetic analyses, we preliminary clarified the intricate taxonomic relationships among Tongoloa and related taxa. These results provide valuable opportunities for a deeper understanding of the phylogeny of Tongoloa.

Genome-wide identified VvOFP genes family and VvOFP4 functional characterization provide insight into fruit shape in grape

Ovate Family Proteins (OFPs) are emerging as novel transcriptional regulators of fruit shape. Despite their established role in various species, their involvement in regulating grape fruit shape remains understudied. This study encompassed a comprehensive evaluation of 16 grape OFP genes in total at the whole genome level. Phylogenetic and synteny analyses established a close relationship between grape VvOFP genes and their tomato counterparts. Expression profiling post-treatment with gibberellic acid (GA3) and thidiazuron (TDZ) revealed that certain OFP genes responded to these regulators, with VvOFP4 showing peak expression three days post-anthesis. Functional assays via overexpression of VvOFP4 in tobacco and tomato altered the morphology of both vegetative and reproductive organs, including leaves, stamens, and fruits/pods. Paraffin sections of transgenic tobacco stems and tomato fruits demonstrated that VvOFP4 overexpression modifies cell dimensions, leading to changes in organ morphology. Additionally, treatments with GA3 and TDZ similarly influenced the shape of grape pulp cells and thereby the overall fruit morphology. These findings suggest that the VvOFP4 gene plays a crucial role in fruit shape determination by modulating cell shape and presents a potential target for future grape breeding programs aimed at diversifying fruit shapes.

An integrative taxonomy of Asian Caryodaphnopsis (Lauraceae) based on morphology and phylogenomics

AbstractCaryodaphnopsis is a small genus of the Lauraceae family with disjunct distribution in tropical Asia and tropical America. Taxa from each region form a well­supported monophyletic clade. However, the species circumscription in Asian Caryodaphnopsis remains ambiguous due to few and generally unstable morphological characters used for classification. To address this, we conducted an integrative taxonomy of the Asian clade. We investigated 13 populations, sampled 57 accessions covering the entire taxonomic diversity, geographic range, and morphological variation in Asia, and reconstructed a new phylogeny using single‐nucleotide polymorphisms. We obtained a well‐resolved phylogeny of the Asian Caryodaphnopsis. The first diverged clade consists of three species endemic to lowland forests. The second (largest) clade (eight species in total) mainly occurs in limestone mountain forests and has a double‐layered lower leaf epidermis morphology of type 2 (less complete roomy with closed “roof”) and type 3 (complete roomy with closed “roof”). Based on the diagnostic morphological characters, distinct distributional ranges, and monophyly of each clade, we recognize 12 species in the Asian Caryodaphnopsis, including three new species: C. cangyuanensis sp. nov., C. hekouensis sp. nov., and C. rubrinervis sp. nov. We also reinstate C. latifolia, and re‐circumscribe the widespread C. tonkinensis and other species based on fruit and inflorescence morphology and molecular evidence.

Forest cover, tree structure, and fruit size as predictors of fruit consumption by birds in two tropical trees from southern Mexico

We evaluate the effect of some variables related to fruit morphology, tree structure, and forest cover on fruit consumption by birds in the tree species Conostegia xalapensis (Melastomataceae) and Bursera simaruba (Burseraceae), in a semi-humid forest of southern Mexico. Foraging observations were made in 20 trees per species from November 2020 to June 2021. We recorded a total of 18 and 22 bird species consuming the fruits of B. simaruba and C. xalapensis, respectively. Flycatchers preferred fruits of B. simaruba, while thrushes largely consumed fruits of C. xalapensis. For large birds, crop size and foliar height diversity were the most influential variables in the removal of B. simaruba fruits, while small birds were positively correlated with the foliar coverage. For C. xalapensis, forest cover negatively influenced fruit consumption by large birds, while the fruit polar diameter had a positive effect on fruit consumption by small birds. Fruit consumption of C. xalapensis by specialist birds showed a positive relationship with forest cover, while the generalists showed a negative relationship. Decreased fruit removal was observed for B. simaruba by both specialist and generalist birds in forest landscapes. Our results can help understand the drivers of the frugivore-plant relationship in semi-humid tropical forests.

Correlations among New Mexico pod‐type green chile (Capsicum annuum) fruit morphology characteristics with destemming force

AbstractDestemming refers to the removal of the calyx and pedicel from chile (Capsicum annuum) fruit, and destemming force is the amount of force required to accomplish this removal. The objective of this study was to describe the relationship between destemming force and fruit width, fruit length, and pericarp thickness, along with the genetic potential for combining the easy‐destemming attribute with the preferred fruit morphology of New Mexico (NM) pod‐type green chile. This investigation will define optimal selection criteria for reducing destemming force, while preserving the distinctive morphology of NM pod‐type green chile. We quantified phenotypic and genetic variation of 285 F3 families from three populations developed from reciprocal crosses between three NM pod‐type cultivars and an easy‐destemming cultivar. The results show destemming force exhibited significant positive phenotypic correlations with pericarp thickness and fruit width (0.90 and 0.92, respectively) and fruit length (0.69). Genetic correlations for each of the three populations for fruit morphological traits ranged from 0.2 to 0.9, with pericarp thickness with the highest genetic correlation with destemming force. Narrow‐sense heritability values were between 0.2 and 0.8, with destemming force and fruit length consistently having higher narrow‐sense heritability values. These findings suggest a correlation between the expression of pericarp thickness and destemming force. The lower estimates for pericarp thickness indicate environmental influences may play a more significant role in determining trait expression. The information generated from this study will aid in the development of efficient cultivars suited for mechanical harvesting in NM pod‐type breeding programs.

Efecto de la UV-C en la calidad postcosecha de cítricos de la región nororiente del Valle del Cauca, Colombia

Ultraviolet short wave (UV-C) irradiation is an emerging technology employed in postharvest fruits treatment. This method facilitates a reduction in microbial load, triggers an elicitor effect, and prolongs the shelf life of fruits. In this study, UV-C was applied to rangpur red lime, Tahitian lime, and sweet orange cv. 'Sweety,' which are the primary citrus varieties cultivated in the northeastern region of Valle del Cauca, Colombia. The citrus fruits were exposed to UV-C irradiation for 5 min using a lamp positioned 11 cm above the work area. Subsequently, the fruits were stored in plastic baskets for 21 days at 26 °C with a relative humidity of 70%. Positive and negative control treatments were also implemented. The positive treatment involved samples treated with a 150 mg/L sodium hypochlorite solution for 5 min, while the negative treatment comprised samples without any postharvest treatment. The results revealed that UV-C application effectively delayed maturation, prevented granulation, and maintained the physicochemical parameters, morphology, and surface color of citrus fruits. In conclusion, UV-C shows promise as a technology for treating citrus fruits during the postharvest stage, offering a means to mitigate losses, and assuring food availability.

Identification of QTLs involved in destemming and fruit quality for mechanical harvesting of New Mexico pod-type green chile.

Domestic production of pepper (Capsicum spp.) is shrinking while demand within the US is growing. Lack of availability and cost of labor often present an obstacle for domestic producers both practically and economically. As a result, switching to harvesting peppers mechanically is anticipated as a key strategy to help domestic producers compete in the international market. Mechanical harvest efficiency can be improved through breeding. One important trait that mechanical harvest compatible material should have is an easy destemming trait: low force separation of the pedicel and calyx from the fruit. To detect the genetic sources underlying a novel easy destemming trait for the purpose of future breeding efforts in New Mexico pod-type green chile, we performed QTL analysis on three F2:F3 populations, coming from three New Mexico pod-type varieties: 'NuMex Odyssey,' 'NuMex Iliad,' and 'NuMex Joe E. Parker,' each crossed with a parent with an easy destemming trait: MUC14. Genotyping was done through genotyping by sequencing (GBS) and phenotyping was done for destemming and fruit trait measurements. Correlations between measurements were found through the R package hmisc and QTL analysis was done through R/qtl. A strong relationship was seen between destemming and aspects of fruit morphology, particularly, destemming force and fruit width (Pearson's correlation coefficient r=0.75). Major QTLs for destemming and fruit size were discovered. Of these, the largest destemming force QTLs for all populations (PVE=34.5-69.9%) were on chromosome 10, and in two populations QTLs for destemming force were found on chromosome 3 (Percent Variance Explained (PVE)=10.7-18.8%). Fruit size-related QTLs in all populations colocalized in these same areas on chromosomes 3 and 10. This suggests that fruit shape may be genetically linked to destemming, and breeders interested in selecting for easy destemming pepper will also have to pay attention to fruit size and shape.