Resistance to Ceratocystis Wilt (Ceratocystis fimbriata) in Parents and Progenies of Eucalyptus grandis x E. urophylla

Abstract

Ceratocystis wilt, caused by Ceratocystis fimbriata, is one of the most damaging diseases in eucalyptus plantations worldwide. Although there are resistant genotypes, the genetic basis of resistance is still poorly understood. In this paper we studied the resistance level by a stem inoculation experiment of genotypes of Eucalyptus grandis and E. urophylla and estimated the heritability and gains of selection in families derived from controlled interspecific crosses. In both species, highly resistant as well as highly susceptible genotypes to Ceratocystis wilt were found. Out of 21 parents assessed, twelve were resistant and nine susceptible. Estimates of individual narrow (50 %) and broad (59 %) sense heritability suggested a high degree of genetic control and low allelic dominance of the trait. There was great genetic variation among and within families, a fact that contributes to high heritability and genetic gain. A genetic gain in lesion size of up to -74.4 % was obtained from selection of the 50 best clones in the evaluated families, i.e., the mean lesion length in the progeny population can be reduced by 74,4 %.

Heritability ofUlmus minorresistance toDutch elm disease and its relationship to vessel size, but not to xylem vulnerability to drought

“…The heritability for the resistance to wilting diseases in other species is supported by several quantitative genetic studies, e.g. in the Fusarium xylarioides–Coffea canephora or Ceratocystis fimbriata–Eucalyptus systems (Rosado et al ., ; Musoli et al ., ). As tree breeding programmes expect that genetic gains will be cumulative over generations, an additive genetic effect guarantees the efficiency of selection, and strengthens the ability to generate a bank of genetic resources of U. minor resistant to DED conserving the genetic integrity of the native species.…”

Software Selegen-REML/BLUP: a useful tool for plant breeding

“…The software Selegen-REML/BLUP has been used internationally (Colombari et al 2013, Oliveira et al 2012, Pedrozo et al 2011, Rosado et al 2010, Dunlop et al 2005, and is a very useful tool for plant breeding. …”

QTL mapping for resistance to Ceratocystis wilt in Eucalyptus

“…The isolate SBS-1 of C. fimbriata used in this study was obtained in 2007 from a hybrid E. grandis × E. urophylla clone exhibiting typical symptoms of the disease in the region of Teixeira de Freitas, Bahia, and used previously (Rosado et al 2010a). The isolate was maintained in the mycology collection of the Forestry Pathology Lab at the Universidade Federal de Viçosa (UFV) in Brazil, on malt agar media at −80°C.…”

“…Genetic studies using hybrid progenies of E. grandis × E. urophylla showed that resistance to Ceratocystis wilt displays a high degree of additive genetic control with seemingly low dominance (Rosado et al 2010a). Nevertheless, the identification of genomic regions involved in the resistance response to Ceratocystis wilt could help understand the genetic architecture of heritable resistance underlying the overall resistance phenotypes and possibly help accelerate the selection of resistant trees (Grattapaglia and Kirst 2008).…”