Background and Aims:

The genus Persea, of the family Lauraceae, includes the subgenera Persea and Eriodaphne, both with great variability and distribution in America. In Mexico, in a low deciduous forest environment in the south of the State of Mexico, a new type of avocado was found. It stands out for its thick fruit exocarp, abundant leaf pubescence and vigorous growth. It is morphologically distinct from described species or races of Persea, similar in some morphological characteristics to P. floccosa and P. tolimanensis, and in exocarp thickness to the latter. It shares habitat with P. americana var. drymifolia, but its parentage is ambiguous. The objective of the study was to describe morphologically and molecularly two populations of the new type of avocado and compare it with P. floccosa, P. tolimanensis and P. americana var. drymifolia.

Methods:

Thirteen samples of the new genotype were collected in Ixtapan del Oro and Zumpahuacán, Mexico. Sixty-four characteristics based on IPGRI and UPOV morphological guidelines were analyzed using discriminant and conglomerate methods. Molecularly eight RAPD and six ISSR primers were used. Using Jaccard similarity distance, as well as Neighbor-Joining and UPGMA clustering methods, dendrograms were constructed. Polymorphic information content (PIC), resolving power (RP) and marker index (MI) were generated.

Key results:

Pubescence, undulation, and shape of leaves grouped individuals together, while sepal pubescence and width, anise odor, and fruit exocarp thickness separated them. RAPD generated 1417 bands from 250 to 900 bp, and ISSR 917 bands from 200 to 1000 bp. The PIC and RP were 0.45 and 0.49 and 8.8 and 5.81, respectively. The dendrograms allowed to distinguish the hybrid from the reference species.

Conclusions:

The new genotype comes from natural hybridization of P. americana var. drymifolia, its polymorphic character is confirmed, and it could be considered a new botanical variety.

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