Resistance to scab caused byVenturis pirinain interspecific pear (Pyrusspp.) hybrids

Abstract

The genetics of resistance to Venturia pirina was investigated from 2002 to 2004 on 11 families derived from interspecific crosses between European and Asian pear species. Nearly complete leaf resistance to V. pirina was identified in all progeny of families with at least 50% Asian pear (Pyrus pyrifolia and/or Pyrus × bretschneideri) ancestry, but up to 26% of these trees exhibited fruit scab incidence in any one of three years. However, between 67% and 80% of the scab leaf resistant individuals had fruit russet spotting owing to scab infection in one or more years over the duration of the trial and between 14% and 36% of the leaves were affected by russet spot. The level of affected individuals did not appear to decrease with increasing proportion of Asian parentage for leaves or fruit. In contrast, reference families derived from European pears and many of the families with 12-25% Asian parentage were almost 100% susceptible to scab on both leaves and fruit. In European families, only 2% of these individuals had leaves affected by russet spotting, whereas an average of 23% of fruit were affected. The genetics of non-host resistance is discussed.

Identification of Pyrus Single Nucleotide Polymorphisms (SNPs) and Evaluation for Genetic Mapping in European Pear and Interspecific Pyrus Hybrids

“…The T003×M population was developed to study the genetic basis of resistance to pear scab ( Venturia pirina ), fire blight ( Erwinia amylovora ), pear psylla ( Cacopsylla pyri ) and pear sawfly ( Caliroa cerasi ). T003 (as most Asian pears in general) is not host to V. pirina [45], [46] and a good source of resistance to C. pyri and C. cerasi [47], while ‘Moonglow’ derives from fire blight-resistant cultivars ‘Roi Charles Würtenberg’ and ‘Seckel’. The T042×T081 population was created to develop an understanding of the genetic control of scab resistance in pear.…”

A new pear scab resistance gene Rvp1 from the European pear cultivar ‘Navara’ maps in a genomic region syntenic to an apple scab resistance gene cluster on linkage group 2

“…Recent studies underline the putative favourable effect of combining both major resistance genes and quantitative resistance factors in a same genotype (Palloix et al 2009;Brun et al 2010). Scab resistance studies performed on leaves have also to be extended to scab resistance on fruits since the correlation is not complete especially in interspecific hybrids as shown by Brewer et al (2009). Thus, exploring quantitative resistance to pear scab on both leaves and fruits will be a major goal for the coming years.…”

Evaluation of Venturia pyrina virulence on European pear (Pyrus communis) cultivars by an in vitro methodology

“…The majority of the data on pear resistance to scab is based on the cultivar performance in the field, and only a few studies on a systematic and comprehensive screening of germplasm collections are available (Brewer et al., 2009; Brown, 1960; Kemp & van Dieren, 2000; Lācis et al., 2015; Postman et al., 2005). Morphological changes in leaf tissues of resistant and susceptible pear cultivars during the infection by the pathogen have been characterized, and proofs for the ontogenic and polygenic resistance have also been demonstrated (Brewer et al., 2009; Chevalier et al., 2002,2004; Chevalier, Tellier, Lespinasse, & Caffier, 2008). Studies on resistance mechanisms of pear to V .…”