Introduction
Peru is one of the major centres of maize diversity, with 52 races described across environments ranging from coastal areas to the Andean highlands (Guzzon et al. Reference Guzzon, Arandia Rios, Caviedes Cepeda, Céspedes Polo, Chavez Cabrera, Muriel Figueroa, Medina Hoyos, Jara Calvo, Molnar, Narro León, Narro León, Mejía Kerguelén, Ospina Rojas, Vázquez, Preciado-Ortiz, Zambrano, Palacios Rojas and Pixley2021; Fuentes-Cardenas et al. Reference Fuentes-Cardenas, Cuba-Puma, Marcilla-Truyenque, Begazo-Gutiérrez, Zolla, Fuentealba, Shetty and Ranilla2022). This diversity reflects a long history of farmer selection and adaptation to heterogeneous environments (Salvador-Reyes and Clerici Reference Salvador-Reyes and Clerici2020; Zambrano et al. Reference Zambrano, Yánez and Sangoquiza2021; Fuentes-Cardenas et al. Reference Fuentes-Cardenas, Cuba-Puma, Marcilla-Truyenque, Begazo-Gutiérrez, Zolla, Fuentealba, Shetty and Ranilla2022). Landraces maintained in traditional farming systems constitute valuable plant genetic resources, and their continued cultivation on farm contributes to maintaining crop genetic diversity (Jarvis et al. Reference Jarvis, Brown, Cuong, Collado-Panduro, Latournerie-Moreno, Gyawali, Tanto, Sawadogo, Mar, Sadiki, Hue, Arias-Reyes, Balma, Bajracharya, Castillo, Rijal, Belqadi, Rana, Saidi, Ouedraogo, Zangre, Rhrib, Chavez, Schoen, Sthapit, De Santis, Fadda and Hodgkin2008).
Despite this diversity, the scientific characterization of Andean maize landraces remains limited (Fuentes-Cardenas et al. Reference Fuentes-Cardenas, Cuba-Puma, Marcilla-Truyenque, Begazo-Gutiérrez, Zolla, Fuentealba, Shetty and Ranilla2022). The Tacna region encompasses a marked environmental gradient from coastal valleys to high Andean agricultural areas. Water availability is particularly relevant to starchy maize cultivation in Peru, as precipitation-related variables and prolonged dry periods have been identified as important determinants of yield (Laudien et al. Reference Laudien, Schauberger, Gleixner and Gornott2020). Floury maize landraces continue to be maintained by local farmers across these traditional agricultural areas. The present study aimed to document and characterize floury maize landraces maintained under traditional on-farm cultivation in the Tacna region by integrating information on their geographic distribution, farming practices, and ear and kernel morphological diversity.
Experimental
Field surveys were conducted between April 2021 and June 2023 in the Caplina, Locumba and Sama hydrographic basins of the Tacna region, southern Peru, covering 18 districts and 35 localities (Figure 1; Table S1). These basins encompass a pronounced altitudinal climatic gradient, with temperatures decreasing towards the high Andes and annual precipitation increasing from
Location of the Tacna region in Peru and geographic distribution of the collection sites where 178 floury maize accessions were obtained. The inset shows the altitudinal distribution of the collected accessions across the Caplina, Locumba and Sama hydrographic basins using a beeswarm plot with boxplots.
Figure 1 Long description
A) Main map of the Tacna region with labeled places, boundaries, a legend and collection site points. Text labels on the map include, CANDARAVE, TARATA, TACNA and LOCUMBA. A set of circular point markers is distributed across the region. The legend lists, Accession, Provincial capital, Provincial boundary and Departmental boundary. The legend also includes, Altitude left parenthesis m a s l right parenthesis, with two labeled endpoints, High colon 5800 and Low colon 0. A scale bar at the bottom is labeled, Kilometers, with tick labels 0, 25 and 50. B) Locator inset map showing Peru with the Tacna region highlighted by a boxed area. Country labels visible in the inset include, Ecuador, Colombia, Brazil, Bolivia and Peru. A scale bar in the inset is labeled, Kilometers, with tick labels 0, 300 and 600. C) Beeswarm plot with boxplots comparing altitude distributions across three basins. The x axis category labels are, Caplina, Locumba and Sama, with the x axis title, Basin. The y axis label reads, Altitude left parenthesis m a s l right parenthesis. The y axis tick labels shown are 0, 500, 1500, 2500, and 3500. Each basin has a vertical boxplot with whiskers and multiple individual points plotted as a beeswarm. Numeric values for individual points are not printed next to the points.
approximately 10 mm in coastal areas to 240–440 mm at higher elevations (Autoridad Nacional del Agua, 2008). Farmers cultivating floury maize were identified mainly through local agricultural agencies, community leaders and farmers’ representatives. Consistent with Maxted et al. (Reference Maxted, Veteläinen, Negri, Veteläinen, Negri and Maxted2009), structured face-to-face interviews documented farmer characteristics and aspects of maize cultivation and management, including crop seasonality, land use, seed sources, production constraints and maize uses (Table S1). Participation was voluntary and informed consent was obtained verbally. During the same field visits, maize ears were collected from 110 participants, yielding 178 accessions, each representing a farmer-recognized floury maize landrace.
The 178 accessions were taxonomically identified as Zea mays L. var. amylacea by Dr Rosario Elena Zegarra Zegarra and conserved ex situ as ears containing seeds at the Botany and Genetic Resources Laboratory, Universidad Nacional Jorge Basadre Grohmann, Tacna, Peru. Nineteen ear and kernel traits (14 quantitative and 5 qualitative) were evaluated following IBPGR (1991) and Muñoz et al. (Reference Muñoz, Giraldo and Fernández de Soto1993). For each accession, 4–18 ears were evaluated, depending on availability. Individual ear measurements are provided in Table S5; accession means were calculated for quantitative traits (Table S6), whereas the predominant category (mode) was determined for qualitative traits (Table S8). Accession means were used to calculate descriptive statistics across the collection (Table S7).
Discussion
The survey documented 178 floury maize accessions across 35 localities and 18 districts of the Tacna region. Most accessions (164 of 178) were collected from 30 localities above 2000 metres above sea level, showing that high-Andean farming areas were strongly represented in the germplasm documented in this study (Figure 1; Table S1). Cultivation was predominantly small-scale: among the 96 farmers reporting maize area, 74 (77.1%) cultivated ≤0.50 ha, and self-consumption was reported by 84 of the 90 respondents to this question (Figure S1; Table S1). Among respondents reporting cropping patterns, 68.1% practised crop rotation, and 75.6% of those reporting seed origin used farmer-saved seed (Table S4). This small-scale, predominantly self-consumption-oriented production is consistent with the broader pattern reported for starchy maize in Peru, largely based on smallholder agriculture and self-consumption (Laudien et al. Reference Laudien, Schauberger, Gleixner and Gornott2020). Among respondents reporting age, 78.2% were ≥51 years old, and many respondents reported several decades of maize cultivation experience (Tables S1–S3). Collectively, these findings characterize a traditional farming system based on small-scale production, experienced farmers and farmer-saved seed, with limited introduction of seed from outside the local production system. This management context highlights the central role of farmers in maintaining and reproducing these landraces across successive cropping cycles, thereby contributing to their conservation on farm (Perales et al. Reference Perales, Brush and Qualset2003; Bellon et al. Reference Bellon, Mastretta-Yanes, Ponce-Mendoza, Ortiz-Santa María, Oliveros-Galindo, Perales, Acevedo and Sarukhán2021; Guzzon et al. Reference Guzzon, Arandia Rios, Caviedes Cepeda, Céspedes Polo, Chavez Cabrera, Muriel Figueroa, Medina Hoyos, Jara Calvo, Molnar, Narro León, Narro León, Mejía Kerguelén, Ospina Rojas, Vázquez, Preciado-Ortiz, Zambrano, Palacios Rojas and Pixley2021).
Morphological characterization provides a useful approach for documenting phenotypic variation within plant genetic resources and identifying potentially valuable germplasm (Belalia et al. Reference Belalia, Lupini, Djemel, Morsli, Mauceri, Lotti, Khelifi-Slaoui, Khelifi and Sunseri2019). In the present collection, substantial variation was observed among the accessions, although its magnitude differed markedly among traits. The greatest relative variation occurred in cob weight (coefficient of variation = 45.15%), ear weight (34.01%), 100-grain weight (24.22%), number of kernels per row (20.89%) and grain thickness (20.54%), whereas cob filling percentage showed the lowest variation (4.12%) and several ear and grain dimensions also varied comparatively little (Figure S2; Tables S6 and S7). Wide ranges were also observed for several traits, including ear weight (44.54–297.09 g), 100-grain weight (6.85–85.55 g) and cob weight (3.54–38.52 g) (Table S7). These patterns indicate substantial morphological variation, particularly in weight-related traits, kernel number and grain thickness. Substantial variability in ear and grain traits has also been reported in other maize germplasm collections (Rahman et al. Reference Rahman, Mia, Quddus, Hassan and Haque2015; Ferdoush et al. Reference Ferdoush, Haque, Rashid and Bari2017; Singh et al. Reference Singh, Kumar and Jasmine2017; Islam et al. Reference Islam, Ferdausi, Sweety, Das, Ferdoush and Haque2020).
Qualitative traits further illustrated this diversity. Irregular grain-row arrangement and white cob colour predominated in 171 and 166 accessions, respectively, whereas greater variation occurred in ear shape, grain type and grain colour. Pointed and jagged grain types were frequent, and white, marbled and mottled grains were the most common predominant grain-colour categories (Table S8). Variation in ear and kernel morphology is also evident among selected accessions (Figure 2). As the accessions were collected directly from farmer-managed fields, the observed variation represents phenotypic variation expressed under on-farm conditions and should not be interpreted as evidence of genetic differences among accessions.
Morphological diversity of selected floury maize accessions collected from traditional farming systems in the Tacna region, Peru. (A) Representative ears together with kernel details illustrating variation in ear size and shape, cob colour, and grain characteristics. (B) Representative kernels illustrating variation in grain colour, shape and size. Accession codes are indicated in each image.
Overall, the collection documents substantial morphological variation within farmer-managed floury maize germplasm from Tacna, with strong representation of accessions from high-Andean farming areas. Its morphological characterization, together with the associated geographic and management information, provides baseline information for its documentation and management and a basis for future genetic characterization and agronomic evaluation.
Supplementary material
The supplementary material for this article can be found at https://doi.org/10.1017/S1479262126100872.
Acknowledgements
The authors thank Dr Óscar Fernández Cutire for technical assistance, Dr Rosario Elena Zegarra Zegarra for assistance with taxonomic identification and Engineer Patricia Navarro for administrative assistance. The authors also thank the farmers of the Tacna region for providing the maize ears used in this study. ChatGPT (OpenAI, accessed via the ChatGPT web interface in 2026) was used to assist in the preparation of the revised Short Communication, specifically for language editing, text condensation, and improvements in clarity and organization. All AI-assisted text was critically reviewed and revised by the authors, who take full responsibility for the content of the manuscript.
Data Availability Statement
The data that support the findings of this study are available from the corresponding author upon reasonable request.
Funding statement
This work was supported by the Fondos del Canon, Sobrecanon y Regalías Mineras 2020-I from Universidad Nacional Jorge Basadre Grohmann, Peru (Rectoral Resolution No. 8532-2021). Funding for open access publishing: Universidad Pablo de Olavide/CBUA.
Competing interests
The authors declare no conflict of interest.
Ethical standards
The objectives of the study were explained to all participating farmers, and their participation was entirely voluntary. Informed consent was obtained verbally from all participants prior to data collection. The information collected through the interviews was used exclusively for research purposes. The study was conducted in accordance with internationally accepted ethical principles.
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