ALTITUDINAL GENETIC VARIATION OF SEEDLING MORPHOLOGY OF Enterolobium cyclocarpum IN OAXACA, MEXICO

Abstract

Enterolobium cyclocarpum (Jacq.) Griseb. is a tree that is used in reforestation and ecological restoration programs; however, the altitudinal variation of seedling morphology is unknown, which may be an indicator of the adaptation of the species to the environmental conditions of the sites where it can be successfully established. The objectives of this study were to evaluate the morphological variation of E. cyclocarpum seedlings and determine its relationship with altitude and climatic variables of the site of seed provenance. Eleven morphological traits of seedling from 10 provenances were evaluated in the nursery. Significant differences between provenances (P ≤ 0.05) were detected in nine traits. On average, the contribution of provenances to the total variance was 5.08 %. The association between seedling height and the degree days of the site of origin was negative, as was the width of true leaves with the minimum temperature and degree days > 5 °C of the provenance site. Seedling height and diameter at the hypocotyl height had a positive linear association with elevation of the site of origin (R² = 0.55, P = 0.0136; R² = 0.41, P = 0.0456, respectively). Seeds from higher altitudes produce larger seedlings, which may be due to an adaptive response of the species or to maternal effects related to seed size.