Morphological and genetic diversity of traditional varieties of agave in Hidalgo State, Mexico

Abstract

The agaves are plants of cultural importance which have been used by humans for about 10,000 years and about 40 specific uses. The most culturally and economically important of those uses are for the production of fermented (pulque) and distilled beverages (mescal). Pulque continues to be produced in nearly all of Mexico, and the agaves used for this purpose have shown domestication syndrome. We carry out an ethnobotanical, morphological, and genetic analysis of the traditional varieties of pulque agave used in the production of aguamiel (agave sap) and pulque in the state of Hidalgo. We did semi-structured interviews, free listings, and tours with 11 agave managers. We analyzed morphology and studied genetic diversity and structure using nuclear microsatellites. We found wild-collected, tolerated, transplanted, and cultivated varieties of agave. This comprised 19 traditional varieties of pulque agave, 12 of them in production during the study, which corresponded to the species Agave americana, A. salmiana y A. mapisaga and five intraspecific entities. The varieties were grouped morphologically according to a management gradient; the wild-collected varieties were the smallest, with more lateral teeth and a larger terminal spine. The cultivated varieties clearly exhibited domestication syndrome, with larger plants and smaller dentition. The expected heterozygosity (He) of the varieties ranged from 0.204 to 0.721. Bayesian clustering suggested the existence of three genetic groups, both at the level of traditional varieties of pulque agaves and for management categories, a result that matches multivariate clustering. Pulque producers in the studied localities maintain high agrobiodiversity. The cultivated varieties exhibit domestication syndrome, as has been reported for other species of the genus with the same selection purposes. Our results support the hypothesis of a decrease in genetic diversity in crops compared to wild-growing agaves, which seems to be due to vegetative propagation, among other factors.

Agave Fructans in Oaxaca’s Emblematic Specimens: Agave angustifolia Haw. and Agave potatorum Zucc.

“…The first PC was influenced mainly by the characteristics defining the plant size, including plant length, rosette diameter, the number of leaves, leaf length, and leaf width. These results are in accordance with the trends found in other Agave species used for producing fermented and distilled beverages, which confirms that an analysis of only vegetative characteristics is sufficient for distinguishing between Agave species [ 23 , 25 ]. On the other hand, the PCA also showed that the variables can clearly discriminate A. angustifolia individuals by their age, while A. potatorum plants were not so clearly defined.…”

Genomic analyses of wild and cultivated bacanora agave (Agave angustifoliavar.pacifica) reveal inbreeding, few signs of cultivation history and shallow population structure

“…Interestingly, in the Agave genus, relatively high levels of inbreeding (FIS) have also been reported in other studies [43]. For example, considerable inbreeding was reported in wild and cultivated samples of A. maximiliana (FIS range from 0.002 to 0.32; [47]), in A. americana, A. salmiana and A. mapisaga (FIS ranged from 0.19 to 0.72 [68]) and in A. potatorum (FIS ranged 0.21-0.32; [75]).…”

“…The case of agave is probably more complicated, with some cultivated varieties (e.g., A. tequilana, A. salmiana and A. americana) presenting low levels of diversity [40,48,67,68] , whereas in other species levels of genetic variability are indistinguishable or even higher in cultivated individuals in comparison to their wild counterparts [43,47]. Here, we found that cultivated individuals of A. angustifolia in northwestern Mexico have not lost genomic diversity, nor did they present increased inbreeding in comparison to their wild counterparts.…”

Genomic Analyses of Wild and Cultivated Bacanora Agave (Agave angustifolia var. pacifica) Reveal Inbreeding, Few Signs of Cultivation History and Shallow Population Structure

“…The case of agave is probably more complicated, with some cultivated varieties (e.g., A. tequilana, A . salmiana and A. americana ) presenting low levels of diversity [ 46 , 54 , 71 , 72 ], whereas in other species levels of genetic variability are indistinguishable or even higher in cultivated individuals in comparison to their wild counterparts [ 49 , 53 ]. Here, we found that cultivated individuals of A. angustifolia in northwestern Mexico have not lost genomic diversity, nor did they present increased inbreeding in comparison to their wild counterparts.…”

“…salmiana and A . mapisaga ( F IS ranged from 0.19 to 0.72 [ 72 ]) and in A. potatorum ( F IS ranged 0.21–0.32; [ 78 ]).…”