Inheritance of Resistance to Pear Psylla Nymphal Feeding in Pear (Pyrus communis L.) of European Origin

Abstract

<jats:p>Pear psylla are serious pests of pear throughout North America and Europe. Inhibition of nymphal feeding has been identified as a key component of resistance, being correlated with inhibition of oviposition, mortality, and delayed development. Breeding for resistance would be aided by knowledge of the inheritance and relative breeding values of resistant parents. Nine seedling populations derived from crosses among five resistant European <jats:italic>P. communis</jats:italic> cultivars (‘Batjarka’, ‘Erabasma’, ‘Ilinjaca’, ‘Spina Carpi’, and ‘Zelinka’), a clone labeled ‘Obican Vodenac’, and two susceptible <jats:italic>P. communis</jats:italic> parents (‘Bartlett’ and ‘Sunrise’) were used in this study. The seedlings, ‘Bartlett’ as a susceptible control and NY10353 (a <jats:italic>P. communis</jats:italic> × <jats:italic>P. ussuriensis</jats:italic> backcross hybrid) as a moderately resistant control, were assayed for short-term survival and nymphal feeding after an infestation period of 2 days. There were no significant differences among the progenies and controls in mean proportion of live nymphs after 2 days. The distributions of live and feeding nymphs indicated some dominance for susceptibility in some crosses. There were few significant differences among crosses in the proportion of actively feeding nymphs; however, the two crosses involving ‘Erabasma’ exhibited significantly less feeding, indicating that ‘Erabasma’ transmitted resistance to nymphal feeding to its progeny to a greater degree than the other four resistant parents.</jats:p>

Diversity, biology, and management of the pear psyllids: a global look

“…Developing pear cultivars with psyllid resistance using these traditional breeding methods is laborious and time consuming, partly due to the limited understanding of the genetic basis of Pyrus resistance. Resistance to psyllids is thought to be quantitatively inherited (Harris and Lamb 1973), yet resistance often does not transmit well from resistant hybrid lines to progeny (Lespinasse et al 2008, Bell 2013). Resistance traits may result from the combined results of several small-effect resistance genes or from combined dominance and epistatic effects (Pasqualini et al 2006).…”

Genetic mapping of Cacopsylla pyri resistance in an interspecific pear (Pyrus spp.) population

“…On the other hand, resistant cultivars of East European origin did not appear able to transmit high degrees of resistance to nymphal feeding to their progeny, except for 'Erabasma.' Moreover, in crosses involving European pear cultivars, susceptibility was dominant (Bell 2013b). It is important to underline that the studies of Harris and Lamb (1973) and of Bell (2013b), other than using different sources of resistance, evaluated two distinct modes of resistance.…”

“…Moreover, in crosses involving European pear cultivars, susceptibility was dominant (Bell 2013b). It is important to underline that the studies of Harris and Lamb (1973) and of Bell (2013b), other than using different sources of resistance, evaluated two distinct modes of resistance. Therefore, it is clear that the investigation of all types of resistance to pear psylla is fundamental to determine whether a cultivar will be useful for breeding programs.…”

Susceptibility of European pear germplasm to Cacopsylla pyri under Mediterranean climatic conditions

“…Most of these studies were based on field observations (Benedek et al, 2010;Berrada et al, 1995;Bouvier et al, 2011;Braniste et al, 1994;Briolini et al, 1989;Quarta and Puggioni, 1985;Robert et al, 1999;Robert and Raimbault, 2005;Sestras et al, 2009;Stamenković et al, 1994;Szabó et al, 2010), while only few studies were made by the introduction of psylla nymphs or adults in a mesh covered tunnel containing the pear plants (Baldassarri et al, 1996;Pasqualini et al, 2006;Robert et al, 2004). On the contrary, nearly all studies performed in USA on C. pyricola resistance were carried out in the laboratory by rearing psylla nymphs on plant material (Bell, 1984(Bell, , 1992(Bell, , 2003(Bell, , 2013Bell and Stuart, 1990;Berrada et al, 1995;Butt et al, 1988Butt et al, , 1989Puterka et al, 1993;Quamme, 1984). Except for 3 cultivars of French origin and the Italian 'Spina Carpi', most of these genotypes are ancient local varieties from Hungary, former Yugoslavia and Romania.…”

“…All these genotypes are important sources of resistance within the primary gene pool available for improving P. communis cultivars, but unfortunately have often relatively poor fruit quality and some of them, like 'Spina Carpi' does not transfer the resistance to its progeny (Rivalta and Dradi, 1998). Recently, Bell (2013) recommended the Serbian cultivar 'Erabasma', with similar fruit quality to that of 'Spina Carpi', for the development of resistant cultivars as transmitting resistance to nymphal feeding to its progeny to a greater degree than 'Spina Carpi' and the resistant East European 'Batjarka', 'Ilinjaca', and 'Zelinka'.…”