The regulation of anther dehiscence by relative humidity (RH) was assessed for detached anthers and detached whole flowers from a limited selection of apricot (Prunus armeniaca L.), peach [P. persica (L.) Batsch], and almond [P. dulcis (Mill.) D.A. Webb, syn. P. amygdalus Batsch; P. communis (L.) Arcangeli, non Huds.] genotypes, as well as an almond X peach F2 progeny. Dehiscence was evaluated at 33, 64, 87, 93 and 97% RH for detached anthers, and at 33, 64 and 97% RH for whole detached flowers. Anther dehiscence was suppressed with increasing RH for all genotypes. Apricot anthers showed the greatest dehiscence at low RH and measurable dehiscence at high RH even when detached. Anther dehiscence in almond appeared more suppressed than in apricot at all RH levels tested, being completely suppressed by high RH in detached anthers. Peach genotypes exhibited the full range of variability between apricot and almond patterns. Evidence for transgressive segregation of RH-controlled anther dehiscence was observed in the occurrence of cleistogamy in an almond × peach F2 progeny. Rates of anther dehiscence were approximately linear with change in RH in detached anthers but exhibited a more buffered, step-wise response when detached whole flowers were tested. Results are consistent with field observations, and highlight the low but measurable risk of cleistogamy in these species, as well as opportunities to modify the breeding systems and crossing environments to facilitate controlled hybridization, and to reduce pollination vulnerability to adverse environments.
Thomas M. Gradziel and Steven A. Weinbaum
Elizabeth E. Rogers and Craig A. Ledbetter
expected to contribute to increasing the frequency of ALSD. However, because peach × almond ( P. persica × P. dulcis ) hybrids are being increasingly used as rootstocks in California almond orchards, susceptibility of such hybrids are of concern. One
David E. Zaurov, Sasha W. Eisenman, Timothy Ford, Sergei Khokhlov, Sovetbek Kenjebaev, Kaiyrkul T. Shalpykov, and C. Reed Funk
. Amygdalus that are found in the area comprising the former USSR ( Abdurasulov, 1990 ; Dzhangaliev et al., 2003 ; Rubtsov, 1971 ; Zhukovsky, 1971 ). The distribution and significant traits of P . dulcis and closely related species are presented ( Table
W. Vance Baird, Agnes S. Estager, and John K. Wells
Using laser flow cytometry, nuclear DNA amounts were estimated for 12 Prunus species, representing three subgenera [Prunophora (Prunus), Amygdalus, and Cerasus (Lithocerasus)], two interspecific hybrids, four cultivars, and a synthetic polyploid series of peach consisting of haploids, diploids, triploids, and tetraploids (periclinal cytochimeras). Peach nuclear DNA content ranged from 0.30 pg for the haploid nuclei to 1.23 pg for the tetraploid nuclei. The diploid genome of peach is relatively small and was estimated to be 0.60±0.03 pg (or 5.8×108 nucleotide base pairs). The polyploid series represented the expected arithmetic progression, as genome size positively correlated with ploidy level (i.e., DNA content was proportional to chromosome number). The DNA content for the 12 diploid species and two interspecific diploid hybrids ranged from 0.57 to 0.79 pg. Genome size estimates were verified independently by Southern blot analysis, using restriction fragment length polymorphism clones as gene-copy equivalents. Thus, a relatively small and stable nuclear genome typifies the Prunus species investigated, consistent with their low, basic chromosome number (× = 8).
Craig A. Ledbetter and Elizabeth E. Rogers
North America, and almond ( P. dulcis ), a tree nut cultivated almost exclusively in California orchards in North America. Both species are economically important for California and have significant acreage throughout its various growing regions. In 2007
Ossama Kodad, Rafel Socias i Company, Ana Sánchez, and M. Margarida Oliveira
, E. Sutherland, B.C. Godini, A. 2007 Self-(in)compatibility of the almond P. dulcis and P. webbii : Detection and cloning of ‘wild-type S f ’ and new self-compatibility alleles encoding inactive S -RNases Mol. Genet
R. Tao, H. Yamane, H. Sassa, H. Mori, H. Murayama, T.M. Gradziel, A.M. Dandekar, and A. Sugiura
Stylar proteins of four Prunus species, P. avium, P. dulcis, P. mume, and P. salicina, were surveyed by 2D-PAGE combined with immunoblot and N-terminal amino acid sequence analyses to identify S-proteins associated with gametophytic SI in the Prunus. All four S-allelic products tested for P. dulcis could be identified in the highly basic zone of the gel. These S-proteins had Mr of about 28–30 kDa and reacted with the anti-S4-serum prepared from Japanese pear (Pyrus serotina). Two of six S-allelic products tested for P. avium could be also identified in the 2D-PAGE profiles, with roughly the same pI and Mr as those of S-proteins of P. dulcis. Putative S-proteins for P. mume and P. salicina were found in the same area of 2D-PAGE as the area where S-proteins of P. avium and P. dulcis were located. N-terminal amino acid sequence analysis of these proteins revealed that they were similar to S-RNases reported previously.
Jorge Pinochet, Cinta Calvet, Adriana Hernández-Dorrego, Ariadna Bonet, Antonio Felipe, and Marian Moreno
Two trials involving 20 Prunus rootstocks were conducted under greenhouse conditions to screen for resistance to root-knot nematode [Meloidogyne javanica (Treub.) Chitwood]. Many of the tested materials are interspecific hybrid rootstocks and represent new commercial peach (P. persica Batsch) and plum (Prunus sp.) releases or experimental genotypes of Spanish, French, and Italian origin. In the first trial, the rootstocks Adesoto 101 (P. insititia L.), Bruce (P. salicina Lindl. × P. angustifolia Marsh.), Ishtara, AC-952 (P. insititia), Garnem [P. dulcis (Mill.) D.A. Webb × P. persica], Cadaman [P. persica × P. davidiana (Carr.) Franch], and Orotava (P. salicina) were immune or resistant to a mixture of 10 isolates of M. javanica. The remaining rootstocks, Myrocal (P. cerasifera Ehr.), Montclar (P. persica), and Adafuel (P. dulcis × P. persica), were susceptible. In the second screening trial, the plum rootstocks Adesoto 101, Adara (P. cerasifera), Myro-10 (P. cerasifera), Constantí (P. domestica L.), and AD 105 (P. insititia) were immune to the root-knot nematode. Cadaman, G × N No. 17 (P. dulcis × P. persica), and Tetra (P. domestica) were resistant. Laroda F1OP (P. salicina), Myro-almond (P. cerasifera × P. dulcis), and the peach–almond hybrids Mayor, Adafuel, and Sirio were susceptible.
Jose X. Chaparro, Ronald R. Sederoff, and Dennis J. Werner
Total cellular DNA has been extracted from leaves and\or seed of Prunus dulcis, P. persica, P. mira, P. davidiana, P. persica subsp. ferganensis, and P. triloba. Chloroplast restriction fragments have been visualized by Southern blot analysis using heterologous probes from a petunia chloroplast library. Analysis of preliminary data separates the species into three groups. The first contains P. dulcis, P. mira, and P. davidiana; the second P. kansuensis, P. persica, and P. persica subsp. ferganensis; and the third P. triloba.
PCR amplification using oligos for cytosolic glyceraldehyde-3-phosphate dehydrogenase yields genomic fragments approximately 1kb in size from P. dulcis and P. triloba. Sequence analysis will be performed to determine species relationships at the gene level.
Group-author : R. Socias i Company
Pollen tube growth was studied in 10 almond [Prunus amygdalus Batsch, syn. P. dulcis (Mill.) D.A. Webb] selections of the Zaragoza breeding program, whose main objective is the development of self-compatible cultivars. Self-compatibility was evident in eight of the selections, as indicated by the fact that pollen tube growth was similar following self- and cross-pollination. In the other two selections, pollen tube growth differed following self- and cross-pollination, one showing self-incompatibility and the other an irregular progression of crossed pollen tubes. The importance of the style in sustaining pollen tube growth was evident, and pollen tube growth was influenced by style type.