Selection of Pityrocarpa moniliformis (Benth.) Luckow & R. W. Jobson mother trees for seeds production

Abstract

Even though the growing demand for seeds of native forest species, for both commercial and reforestation purposes, this sector still has some challenges for the large-scale production. Harvesting of these seeds frequently takes place in natural populations, areas not registered for such use, not considering sampling criteria that guarantee their genetic conservation. Due to the economic and socio-environmental importance of Pityrocarpa moniliformis (Benth.) Luckow & R. W. Jobson, a species native to the semiarid region of Brazil, this study aimed to select mother plants of P. moniliformis for seed production that meets the quality requirements demanded by the forest conservation and production programs. To that end, seeds from 44 trees were subjected to evaluation of physical and physiological aspects as well as of genetic diversity from mother plants and progenies by using ISSR molecular markers. There was considerable variation on the physiological quality of seeds, where 77% of P. moniliformis trees produced seeds with germination above 50%. The progeny test showed that 64.4% of the source from total variation in the loci comes from the progenies, indicating an increased difference between generations. By considering the phytosanitary aspect, yield (800 seeds/individual) and seed viability (> 50%), as well as genetic diversity (Nei genetic distance < 0.78 and progeny test), it was possible to select 27 P. moniliformis mother plants with superior characteristics for seed production. Even though physical and physiological quality are important parameters in selecting mother plants for producing seeds intended for commercialization, the access to the genetic diversity of P. moniliformis assists in selecting mother plants aiming at the recovery of degraded areas, reforestation and genetic breeding. Seed-producing mother plants of P. moniliformis can be selected based on the genetic distance between individuals and on the physiological quality of their seeds.