Nitrogen is the most important element for maintaining growth and high productivity in tree fruits ( Titus and Kang, 1982 ). Sweet cherries ( Prunus avium L.) on precocious, interspecific ( P. cerasus × P. canescens ) Gisela® (Gi) rootstocks (e
Meiosis and pollen viability of Prunus avium L. cv. ‘Lambert’ were investigated to ascertain whether there were annual or regional effects on the incidence of abnormal meiosis or pollen abortion. Studies of meiosis failed to reveal marked variation among the 3 years investigated. Comparisons between 2 similar and 2 dissimilar locations also failed to reveal marked variability in the incidence of abnormal meiosis which was estimated to be 9.62 ± 1.93%. Examination of microspore development showed that pollen abortion occurred prior to the first mitotic division of the microspore nucleus. Studies of mature pollen failed to reveal significant differences in pollen abortion among the 3 years investigated. Differences between the 2 locations and 2 types of blossom sample used also were non-significant. The mean incidence of pollen abortion was 41.6%.
Most sweet cherry (Prunus avium L.) cultivars grown commercially in the Pacific Northwest U.S. are susceptible to powdery mildew caused by the fungus Podosphaera clandestina (Wall.:Fr.) Lev. The disease is prevalent in the irrigated arid region east of the Cascade Mountains in Washington State. Little is known about genetic resistance to powdery mildew in sweet cherry, although a selection (`PMR-1') was identified at the Washington State Unive. Irrigated Agriculture Research and Extension Center that exhibits apparent foliar immunity to the disease. The objective of this research was to characterize the inheritance of powdery mildew resistance from `PMR-1'. Reciprocal crosses between `PMR-1' and three high-quality, widely-grown susceptible cultivars (`Bing', `Rainier', and ëVaní) were made to generate segregating progenies for determining the mode of inheritance of `PMR-1' resistance. Progenies were screened for susceptibility to powdery mildew colonization using a laboratory leaf disk assay. Assay results were verified by natural spread of powdery mildew among the progeny seedlings in a greenhouse and later by placement among infected trees in a cherry orchard. Progenies from these crosses were not significantly different (P > 0.05) when tested for a 1:1 resistant to susceptible segregation ratio, indicating that `PMR-1' resistance is conferred by a single gene, which we propose to designate as PMR-1.
Dwarfing rootstocks in sweet cherry (Prunus avium L.) have been planted worldwide. No single theory has emerged to answer why scion dwarfing occurs in fruit trees. This research examines the vascular pathway in a dwarfing cherry system to determine if physical limitations alter water transport as a possible dwarfing mechanism. Second-leaf `Lapins' trees grafted onto Gisela 5 (Gi5; dwarfing) and Colt (vigorous) rootstocks were field-grown in East Lansing, Mich. During maximum shoot elongation, trees were dug, placed into containers with safranin dye solution (0.1% w/v) for 6 hours and then removed for division (3-5 cm in length) based on location in scion, graft union, and rootstock tissue. Tissues were sectioned using a sliding microtome (120 μm) for examination with a laser confocal microscope (Zeiss LSM Pascal). Mean stem area and vessel diameter were measured; and mean hydraulic diameter was calculated for vessels in the area of dye translocation. Overall, Lapins/Gi5 stem area in the graft union was larger compared to Lapins/Colt; however dye translocation in Lapins/Gi5 was reduced compared to other tissues in the tree. Confocal microscopy indicated dye uptake through the grafted region was more uniformly distributed in Lapins/Colt than in Lapins/Gi5, with dye accumulation in areas of maximum translocation. Vessel diameter did not differ in these areas of translocation. However, in both combinations there was a reduction in mean hydraulic diameter of graft union sections, suggesting a reduction in vessel efficiency to translocate water in this region. Vascular system anomalies were more frequent in Lapins/Gi5, disrupting acropetal dye translocation. This suggests the greatest reduction in vascular transport is in Lapins/Gi5.
In deciduous fruit trees, some storage reserves accumulate during fall and are used for early spring growth. In sweet cherry (Prunus avium L), stored reserves are critical for early growth and there is a transition phase during which current photoassimilates become the primary source for support of reproductive and vegetative sinks. As little is known about this transition, an experiment using 4-year-old `Regina' sweet cherry on the semidwarfing rootstock, Gisela 6, was established. Using whole canopy exposure chambers, five trees were pulsed with high levels of 13CO2 on three different dates during fall (Sept.-Oct). At leaf drop, leaves, buds, wood, bark and roots were sampled for GCMS analysis of pre-winter storage reserves. The major storage organs (those which had the highest change in isotopic ratios) were roots and wood in the trunk and branches. During spring, newly developing organs (flowers, fruits and young leaves) were sampled weekly from bloom to stage III of fruit development for additional GCMS analysis. The stored 13C was mobilized and partitioned to flowers, fruits and young leaves from early spring until one week after fruit set. The highest 13C levels in growing sinks were observed between bloom and fruit set. The isotopic composition of new organs did not differ initially (3 May). During the three next sampling dates (10-24 May) reproductive organs had higher 13C levels compared to vegetative growth. The role of storage reserves, as a source of assimilates for early spring growth and their implications for crop development, will be discussed.
Expansins are a class of proteins that stimulate the extension of plant cell walls. Expansins have been found in nearly all growing plant tissues, such as hycopotyls, young seedlings, fibers, internodes, flower petals, and ripening fruits. We isolated two full-length expansin cDNA clones, Pruav-Exp1 and Pruav-Exp2, from sweet cherry (Prunus avium L.) fruit. Pruav-Exp1 has 1048 nucleotides encoding 254 amino acids, while Pruav-Exp2 has 1339 nucleotides encoding 250 amino acids. Deduced amino acid sequences of sweet cherry Pruav-Exp1 and Pruav-Exp2 share 72% identity. A Blast search of the GenBank database with the deduced amino acid sequences of Pruav-Exp1 and Pruav-Exp2 indicated a high sequence identity with other plant expansin genes. Interestingly, Pruav-Exp1 shares 99% identity of amino acid sequence with that of apricot expansin Pav-Exp1. Fragments from the 3' ends of Pruav-Exp1 and Pruav-Exp2 were cloned to generate gene-specific probes. These probes were used to study expansin gene expression in different tissues and during fruit development. Northern blot analysis showed different mRNA expression patterns for each gene. The mRNA of Pruav-Exp1 was expressed at the pink and ripe stages, but not at the early green and yellow stages of fruit development. The mRNA of Pruav-Exp2 was present earlier, from a low level in yellow expanding fruit, increasing to a high level at the pink stage and remaining at this level through the ripe stage. Both mRNAs were also expressed at a low level in flower, but not present in other tissues such as roots, leaves and peduncles. Our study indicates an expansin gene family is present in sweet cherry and suggests that two expansin genes may have different roles during fruit development and ripening.
Correct assignment of self-incompatibility alleles (S-alleles) in sweet cherry (Prunus avium L.) is important to assure fruit set in field plantings and breeding crosses. Until recently, only six S-alleles had been assigned. With the determination that the stylar product of the S-locus is a ribonuclease (RNase) and subsequent cloning of the S-RNases, it has been possible to use isoenzyme and DNA analysis to genotype S-alleles. As a result, numerous additional S-alleles have been identified; however, since different groups used different strategies for genotype analysis and different cultivars, the nomenclature contained inconsistencies and redundancies. In this study restriction fragment-length polymorphism (RFLP) profiles are presented using HindIII, EcoRI, DraI, or XbaI restriction digests of the S-alleles present in 22 sweet cherry cultivars which were chosen based upon their unique S-allele designations and/or their importance to the United States sweet cherry breeding community. Twelve previously published alleles (S1, S2, S3, S4, S5, S6, S7, S9, S10, S11, S12, and S13 ) could be differentiated by their RFLP profiles for each of the four restriction enzymes. Two new putative S-alleles, both found in `NY1625', are reported, bringing the total to 14 differentiable alleles. We propose the adoption of a standard nomenclature in which the sweet cherry cultivars `Hedelfingen' and `Burlat' are S3S5 and S3S9 , respectively. Fragment sizes for each S-allele/restriction enzyme combination are presented for reference in future S-allele discovery projects.
Simple sequence repeats (SSRs) and amplified fragment-length polymorphisms (AFLPs) were used to evaluate sweet cherry (Prunus avium L.) cultivars using quality DNA extracted from fruit flesh and leaves. SSR markers were developed from a phage library using genomic DNA of the sweet cherry cultivar Valerij Tschkalov. Microsatellite containing clones were sequenced and 15 specific PCR primers were selected for identification of cultivars in sweet cherry and for cross-species amplification in Prunus. In total, 48 alleles were detected by 15 SSR primer pairs, with an average of 3.2 putative alleles per primer combination. The number of putative alleles ranged from one to five in the tested cherry cultivars. Forty polymorphic fragments were scored in the tested cherry cultivars by 15 SSRs. All sweet cherry cultivars were identified by SSRs from their unique fingerprints. We also demonstrated that the technique of using DNA from fruit flesh for analysis can be used to maintain product purity in the market place by comparing DNA fingerprints from 12 samples of `Bing' fruit collected from different grocery stores in the United States to that of a standard `Bing' cultivar. Results indicated that, with one exception, all `Bing'samples were similar to the standard. Amplification of more than 80% of the sweet cherry primer pairs in plum (P. salicina), apricot (P. armeniaca) and peach (P. persica L.) showed a congeneric relationship within Prunus species. A total of 63 (21%) polymorphic fragments were recorded in 15 sweet cherry cultivars using four EcoRI-MseI AFLP primer combinations. AFLP markers generated unique fingerprints for all sweet cherry cultivars. SSRs and AFLP polymorphic fragments were used to calculate a similarity matrix and to perform UPGMA cluster analysis. Most of the cultivars were grouped according to their pedigree. The SSR and AFLP molecular markers can be used for the grouping and identification of sweet cherry cultivars as a complement to pomological studies. The new SSRs developed here could be used in cherry as well as in other Prunus species for linkage mapping, evolutionary and taxonomic study.
Self-fertility studies of some sweet cherry ( Prunus avium L.) cultivars and selections Intl. J. Hort. Sci. 10 4 258 260 Beyhan, N. Karakaş, B. 2009 Investigation of the fertilization biology of some sweet cherry cultivars grown in the central northern
Methanol extracts of fresh tissues of ‘Mazzard’ (Prunus avium L.) and ‘Mahaleb’ (P. mahaleb L.) were examined for phenolic composition. The 2 sweet cherry rootstocks differed in 3 phenolic groups; phenolic acids, coumarins, and flavonoids. ‘Mazzard’ contained 5 acids; p-coumaric, o-coumaric, caffeic, p-coumarylquinic and chlorogenic, whereas ‘Mahaleb’ contained mostly o-coumaric acid. ‘Mahaleb’ tissues were rich in coumarin and herniarin, but these were absent in ‘Mazzard’. Three flavonoids; dihydrowogonin, kaempferol and quercetin, were found in ‘Mazzard’. ‘Mahaleb’ contained only kaempferol. These differences in phenolic composition between the 2 rootstocks seemed related to graft-incompatibility.