Fig 1.
Black triangles indicate archaeological sites dated between Formative Period (ca. 1500–500 yr BP) to Late Period (600–400 yr BP). Black dots indicate modern populations of maize used in this study.
Table 1.
Sample material of traditional landraces.
Table 2.
General information of archeological samples.
Fig 2.
Cobs and kernels from archaeological and modern populations.
A) cobs from Pircas sites, B) cobs from Tarapacá 13, C) cobs from Tarapacá Viejo, D) modern cobs from Camiña and Tarapacá respectively. E) kernels from Pircas and Pintados 1307, F) kernels from Tarapacá 13, G) kernels from Tarapacá 49, H) modern kernels from Camiña and Tarapacá, respectively. Scale bar cobs = 8 cm, scale bar kernels = 1cm.
Fig 3.
PCA of archaeological and modern cobs for 10 traits.
First two PCA axes explain 83.59% of the total variance. Yellow dots represent archaeological cobs. Black dots represent modern cobs. The PC1 axis associated with the perimeter variable separates in two groups: modern and archaeological cobs. PERC = Perimeter of cobs; DF = Feret diameter.
Fig 4.
PCA of archaeological and modern kernels for five traits.
First two PCA axes accumulate 88.83% of the total variance. Blue dots represent archaeological kernels from Pintados 1307, yellow dots represent archaeological kernels from Tarapacá 13, orange dots represent archaeological kernels from Tarapacá Viejo, and black dots represent modern kernels. Kernels from Pintados 1307 (Formative Period) are grouped with Tarapacá 13 kernels (Late Intermediate Period-Late Period), while Tarapacá Viejo (Late Period) and modern kernel specimens are distant from the previous ones. AREK = Area of the kernel; TH = Thickness., Circles correspond to individuals assigned to genetic cluster 1 in Structure analysis, triangles correspond to individuals assigned to genetic cluster 2 and squares correspond to individuals with no genetic information.
Fig 5.
A) Histogram of discriminant scores for 10 traits in cobs and, B) five traits in kernels. Light bars show archaeological cobs and kernels; black bars show modern cobs and kernels. Two separated groups are present: modern and archaeological cobs and kernels.
Table 3.
Genetic diversity in archaeological and modern samples.
Fig 6.
Estimated population structure.
Each population assigned in the lower part of the graphic. The graphic is portioned into K = 2 colored segments (green and red segments). The population are separated by black bars and labeled above the figure.
Fig 7.
Cluster dendrogram for FST values for modern and archaeological populations.
Three major groups are observed; modern populations Limaxiña 2 and Camiña Alto 5 are grouped in one branch, populations Chusmiza 1, Huaviña 3, Camiña 4 and Camiña 6 are grouped in a second branch, and the archaeological population) is distant from the rest. Fst value between archaeological and modern populations are listed below each population.
Table 4.
Summarize agronomic information.
Fig 8.
Several ears of Chulpi, Harinoso Tarapaqueño and Capio Chileno from Camiña valley.
Fig 9.
Archeological popcorn ear from Tarapacá.