Crown gall is an important disease of many fruit and nut crops, but little is known about sources of resistance. We screened germplasm from Prunus armeniaca L., P. angustifolia Marsh., P. argentia L., P. avium L., P. besseyi Bailey, P. bokhariensis Schneid., P. brigantica L., P. cerasifera Ehrh., P. cerasus L., P. dulcis (Mill.) D.A. Webb, P. fruiticosa Pall., P. hortulana Bailey, P. insititia L., P. japonica Thunb., P. mahaleb L., P. persica (L.) Batsch, P. serotina Ehrh., P. simonii Carr., P. sogdiana L., and P. webbii (Spach) Vieh. When either main stems or lateral branches of seedlings were inoculated with strains K12 and C58 of Agrobacterium tumefaciens (Smith and Townsend) Conn., the incidence of resistance was less than 10% except in some accessions of P. mahaleb L. where up to 30% of the plants were resistant. Some resistant plants were identified in other species, with P. insititia L. being the most promising. Symptoms based on presence and size of galls should be allowed to develop for up to 90 days after inoculation to reduce the likelihood of misclassifying plants as resistant when they are slightly susceptible.
Cultivars from three cherry species, sour cherry (Prunus cerasus L.), sweet cherry (P. avium L.), and ground cherry (P. fruticosa Pall.), and open-pollinated progenies of P. mahaleb L., P. incisa Thunb., P. canescens Bois., and P. subhirtella Miq., and the sour cherry cultivars Cigany Meggy and Pitic de Iasi were characterized electrophoretically for malate dehydrogenase (MDH) in leaf tissue. No intraspecific variability for MDH isozymes was detected within the sour cherry, sweet cherry, or P. fruticosa cultivars evaluated. The codominant expression of both the sweet cherry and P. fruticosa bands in sour cherry supports the hypothesis that sour cherry arose by interspecific hybridization. A single isozyme band was associated with the mitochondrial subcellular leaf extract from sour cherry. Sweet and sour cherry pollen had activity for a cathodal MDH locus that was not detected in the leaf tissue. Open-pollinated populations of P. mahaleb and P. canescens each exhibited one banding pattern; however, similar progeny from P. subhirtella, P. incisa, and the sour cherry cultivars Pitic de Iasi and Cigany Meggy each segregated for two zymogram patterns. Sufficient polymorphism at the MDH locus has been identified to permit its use as a biochemical genetic marker in interspecific hybridizations.
Plum [ Prunus salicina Lindl. (syn. Prunus triflora Roxb. or Prunus thibetica Franch.)], commonly known as chinese plum or japanese plum, is a diploid (2 n = 2 x = 16) fruit tree native to China. It is one of the most important stone fruit
Sharka or plum pox, incited by plum pox virus (PPV), is a major disease of stone fruit ( Prunus L.) responsible for extensive economic losses ( Lopez-Moya et al., 2000 ; Nemeth, 1994 ). Plum pox virus was first described in Bulgaria in the early
Most of the fruit tree species in the genus Prunus (Rosaceae), including almond [ Prunus dulcis (Mill.) D.A. Webb.], exhibit the S-RNase-based gametophytic self-incompatibility (GSI) system ( de Nettancourt, 2001 ; Yamane and Tao, 2009 ). The
Deep supercooling in Prunus flower buds was related to vascular development. The continuity of the xylem was monitored by following the movement of a water-soluble dye. Dye was translocated into the primordia of 3 Prunus species which do not supercool, but it was not observed to move into the primordia of 11 species which avoid freezing injury by deep supercooling. Dye uptake may provide a simple and inexpensive technique to screen for bud supercooling.
The effects of different levels of phosphorus fertilization and water provision on the mineral nutrition of two clonal rootstocks of Prunus were studied. Two-year-old Prunus seedlings, Hybrid GF677 (Prunus persica × Prunus amygdalus) (PH) and Pollizo Puebla de Soto 101 (Prunus insititia) (PI) were planted in an uncultivated calcareous soil (a Xeric torriorthent derived from marl) under greenhouse conditions. They were drip irrigated with subterranean water of slightly alkaline pH (7.63), EC 0.88 dS·m–1, with a low chloride and high sulphate content. The experiment lasted two annual cycles. In October of the second year the leaf nutrient concentration and dry weight of the total leaf weight were determined in four trees of each combination of rootstock × irrigation level × fertilization treatment. The nutritive state of these trees was analyzed by vector analysis. The results point to a highly significant influence of the rootstock nature on the leaf concentrations of most nutrients. Very low Zn and Cu concentrations were recorded on both rootstocks, for both irrigation levels and several fertilizing treatments. Vector analysis confirmed the Cu deficiency resulting from several of the fertilizing treatments and both irrigation levels in PH rootstocks.
Studies of genetic variation at the DNA level in the tree fruit and nut crop species of Prunus have been very limited. Recently molecular markers based on random amplified polymorphic DNA (RAPD) markers have been shown to be highly useful and efficient gene markers in other plant and animal species. We have used a total of 50 primers (10-mers) with arbitrary nucleotide sequence to identify cultivars of cherry, plum, apricot, peach and almond. A total of 120 accessions of different cultivars were assayed. The variation revealed by RAPD markers was highly species specific in the five Prunus species examined. High levels of polymorphism were observed for almond cultivars whereas sweet cherry revealed the lowest levels of polymorphism for the RAPD primers examined. The implications of these results in the germplasm diversity in the cultivated species of Prunus will be discussed.
Rooted cuttings of `Halford' and `Redhaven' peaches [Prunus persica (L.) Batsch] and `Stanley' (Prunus domestica L.) and `Marianna 2624' (P. cerasifera × P. munsoniana) plums were planted in soil containing ≈38 tomato ringspot virus-(TomRSV) infested nematodes (Xiphinema americanum sensu lato Cobb) per 100 cc. Test- and control-plant sap extracts were made from root and leaf tissues after 10, 22, and 34 weeks. Aliquots of these samples were assayed by mechanical inoculation to Chenopodium quinoa Willd. Total nucleic-acid extracts prepared from the remainder of each sample were analyzed by dot blot hybridization using a cRNA probe for TomRSV. The bioassay identified one `Stanley' and two `Redhaven' infected plants. Hybridization results indicated that two of two `Stanley', three of three `Halford', five of five `Redhaven', and zero of six `Marianna 2624' were infected. Our results demonstrate the sensitivity of molecular hybridization for TomRSV detection in Prunus and substantiate the TomRSV resistance of `Marianna 2624'.
Seedlings or rooted cuttings of 35 lines of peach [Prunus persica (L.) Batsch] and other Prunus spp. were screened for resistance or tolerance to the ring nematode Criconemella xenoplax (Raski) Luc & Raski (Cx). Host reaction to Cx was evaluated by comparing root and shoot growth of infested plants with that of uninfested checks. Reaction of Cx to the host was reflected in nematode density per gram root dry weight (NPGR). Effects of Cx on root growth were not always correlated with increases in Cx per 100 cm3 of soil or in NPGR. Prunus japonica Thunb. and P. tomentosa Thunb. showed no Cx-related growth reduction and had lower Cx densities than most other lines. ‘Lovell’ peach had a smaller root system and fewer Cx per pot than ‘Nemaguard’ peach, but differences in NPGR were not significant. With high inoculum levels, significant differences in NPGR between lines, and in growth parameters within lines, could be detected after 6 months.