Sharka [(plum pox virus (PPV)] mainly affects Prunus species, including apricot (Prunus armeniaca L.), peach (Prunus persica L.), plum (Prunus salicina Lindl., Prunus domestica L.), and, to a lesser degree, sweet (Prunus avium L.) and sour cherry (Prunus cerasus L.). Level of resistance to a Dideron isolate of PPV in seven California almond [P. dulcis (Miller) D.A. Webb], five processing peach cultivars, and two peach rootstocks was evaluated. In addition, almond and peach selections resulting from interspecific almond × peach hybridization and subsequent gene introgression were tested. Evaluations were conducted in controlled facilities after grafting the test genotypes onto inoculated GF305 peach rootstocks. Leaves were evaluated for PPV symptoms during three consecutive cycles of growth. ELISA-DASI and RT-PCR analysis were also employed to verify the presence or absence of PPV. Peach cultivars and rootstocks showed sharka symptoms and were ELISA-DASI or RT-PCR positive for some growth cycles, indicating their susceptibility to PPV. Almond cultivars and almond × peach hybrids did not show symptoms and were ELISA-DASI and RT-PCR negative, demonstrating resistance to PPV. Two (almond × peach) F2 selections as well as two of three backcrossed peach selections also showed a resistant behavior against the PPV-D isolate. Results demonstrate a high level of resistance in almond and indicate potential for PPV resistance transfer to commercial peach cultivars.
P. Martínez-Gómez, M. Rubio, F. Dicenta, and T.M. Gradziel
David Ruiz, Manuel Rubio, Pedro Martínez-Gómez, Jesús López-Alcolea, Federico Dicenta, Encarna Ortega, María Dolores Nortes, Antonio Molina, Antonio Molina Jr., and Jose Egea
849228.1) (absence of symptoms and ELISA-DASI and RT-PCR negatives in leaves), in comparison with the susceptibility of the traditional Spanish cultivars ( Table 1 ). Chilling requirements and blooming time. ‘Cebasred’ and ‘Primorosa’ need ≈38 chill