Effects of pollen contamination and non-random mating on inbreeding and outbreeding depression in a seedling seed orchard of Eucalyptus urophylla

Author(s)

Pupin, Silvelise ^[1] ; Sebbenn, Alexandre M. ^{[2, 1]} ; Cambuim, Jose ^[1] ; da Silva, Alexandre M. ^[1] ; Zaruma, Darlin U. G. ^[3] ; Silva, Paulo H. M. ^{[4, 3]} ; Rosse, Leonardo N. ^[5] ; Souza, Isabel C. G. ^[6] ; Marino, Celso L. ^[3] ; Moraes, Mario L. T. ^[1]

Affiliation

^[1] Univ Estadual Sao Paulo UNESP Ilha Solteira, Ave Brasil Ctr 56, CP 31, BR-15385000 Ilha Solteira, SP - Brazil

^[2] Inst Florestal Sao Paulo IF, CP 1322, BR-01059970 Sao Paulo, SP - Brazil

^[3] Univ Estadual Paulista UNESP Botucatu, Rua Jose Barbosa de Banos 1780, BR-18603970 Botucatu, SP - Brazil

^[4] IPEF, Via Comendador Pedro Morganti 3500, BR-13415000 Piracicaba, SP - Brazil

^[5] Eldorado Brasil, Rodovia BR 158 Km 231, BR-79641300 Tres Lagoas, MS - Brazil

^[6] Suzan Papel & Celulose, Ave Dr Jose Lembo 2215, BR-18207780 Itapetininga, SP - Brazil

• Document type: Journal article
• Source: FOREST ECOLOGY AND MANAGEMENT; v. 437, p. 272-281, APR 1 2019.
• Web of Science Citations: 1

Abstract

Microsatellite loci were used to assess pollen contamination and mating patterns in an Eucalyptus urophylla seedling seed orchard (SO2) along with inbreeding and outbreeding depression in a second generation progeny test (PT2) established with SO2 seeds. We measured survival, diameter at breast height (DBH), and height (H) in S02, PT2, and two other stands (SO1, PT) located at a distance of at least 210 m from S02. Pollen contamination was substantial (11.9%), with the largest proportion coming from the closer SO1 stand (6.1%) than PT (4.7%) and 1.1% from unknown sources. The pollen dispersal pattern was isolation by distance but reached long distances (600 m). PT2 offspring were mainly the result of outcrossing (92.6%), but mating in SO2 was not random due to self-fertilization (7.4%), mating among relatives (6.6%), correlated mating (13.7%), and high male fertility success of trees with large DBH. Thus, families are a mixture of different levels of relatedness and some inbreeding (12.7%). Inbreeding depression was variable among traits; it was higher for selfing (39.6-49.5%) than mating among relatives (11.6-20.9%) and higher for mating between full-sibs (4.4%) than half-sibs (2.2%). Outbreeding depression was higher for pollen immigration from less improved sources (33.9-41.2%). Nonrandom mating resulted in a coancestry (0.152) higher than expected for half-sib families and an overestimation of heritability by 17.8%. Our results indicate that isolation distances greater than 600 m are necessary to avoid pollen contamination in Eucalyptus seed orchards. Furthermore, pollen immigration results in outbreeding depression, and selfing results in higher levels of inbreeding depression than mating among related trees. (AU)

• FAPESP's process: 14/03407-7 - Genetic diversity, mating system and parentage in progenies of eucalyptus urophylla st Blake
• Grantee: Silvelise Pupin
• Support Opportunities: Scholarships in Brazil - Doctorate