GENETIC DIVERSITY IN POPULATIONS OF PULQUERO AGAVES (Agave spp.) IN NORTHEASTERN MÉXICO STATE

Abstract

Six populations of pulquero maguey: ‘Manso’ (Agave salmiana var. ‘Salmiana’), ‘Ayoteco’ (Agave salmiana var. ‘Ayoteco’), ‘Verde’, ‘Carrizo’ (Agave mapisaga Trel), ‘Negro’ and ‘Xilometl’ from fields located in Northeast Mexico State. Those were analyzed: to determine the genetic diversity among and within them, to obtain
the corresponding genetic fingerprints, and to compare and differentiate genetic variants. RAPD (Random Amplified Polymorphic DNA) markers and some morphological variables were analyzed. Analysis of variance showed significant differences (P ≤ 0.01) among populations for the traits: plant height, number of leaves, leaf length and width, number of lateral thorns and length of main thorn. The morphological traits which allowed the separation of populations into four groups were: length of main thorn, and number of lateral thorns which explained 94 % of total variation. The percentage total of polymorphic loci was 73.2 %. Polymorphism in maguey ‘Verde’ was 12.2 % and in ‘Manso’ and ‘Ayoteco’, was 32.5 % thus indicating a low genetic variability within those populations. Nei’s coefficient of diversity (H) of all loci studied in the six populations of maguey was 0.28 ± 0.20, confirming the low diversity within populations. The low
level of genetic flow (Nm = 0.24), suggests that there is less than one migrant per generation among populations. Based on Nei’s genetic identity, the RAPD markers allowed the separation of the maguey populations in two large groups, each including three related variants. In group 1 Agave mapisaga Trel (‘Carrizo’) was related to ‘Verde’ with a value of identity of 0.91, and with maguey ‘Xilometl’ with a coefficient of 0.82. In group 2 a very close association  between the magueyes ‘Manso’ (Agave salmiana var. ‘Salmiana’) and ‘Negro’ (0.89) was found, closely followed by ‘Manso’ and ‘Ayoteco’ (0.83).