Embryo Culture of Lycopersicon esculentum × L. peruvianum Hybrid Genotypes Possessing Heat-stable Resistance to Meloidogyne incognita

Genotypes of Lycopersicon peruvianum (L.) Mill. and L. peruvianum var. glandulosum (Rick), selected from accessions that possess resistance to Meloidogyne incognita [(Kofoid and White) Chitwood] at high soil temperature (30C), were used as male parents in crosses with L. esculentum (Mill.) susceptible cultivars UC82, Lukullus, Tropic, and male-sterile line ms-31, respectively. The incongruity barrier between the two plant species was overcome by embryo callus and embryo cloning techniques. Hybridity of the F, progeny obtained from each cross was confirmed by differences in leaf and flower morphology, plant growth habits, and by acid phosphatase isozyme phenotypes using polyacrylamide gel electrophoresis. In greenhouse inoculation experiments, F1 plants were highly resistant to M. incognita in soil at 25 and 30C. These results confirmed the successful transfer and expression of heat-stable resistance to M. incognita from L. peruvianum to hybrids with L. esculentum as a preliminary step to introgressing additional root-knot nematode resistance into tomato.EEA AMBAFil: Cap, Guillermo Bartolome. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Área Metropolitana de Buenos Aires. Agencia de Extensión Rural La Plata; ArgentinaFil: Roberts, P.A. University of California, Riverside. Department of Hematology; Estados UnidosFil: Thomason, I.J. University of California, Riverside. Department of Hematology; Estados UnidosFil: Murashige, T. University of California, Riverside. Department of Hematology; Estados Unido

Search for the charge-conjugation-forbidden decay ω→ηπ⁰

A new upper limit of 2.3×10<sup>−4</sup> on the branching ratio of the decay ω→ηπ<sup>0</sup> has been obtained using the Crystal Ball multiphoton spectrometer at the Mainz Microtron MAMI. This decay is forbidden by charge-conjugation invariance of the strong and electromagnetic interactions. We have also obtained the upper limit of 2.3×10<sup>−4</sup> for the forbidden decay ω→3π<sup>0</sup> and the upper limit of 2.4×10<sup>−4</sup> for ω→2π<sup>0</sup>

Coherent photoproduction of η-mesons off ³He – search for η-mesic nuclei

Coherent photoproduction of η-mesons off 3He, i.e. the reaction γ3He→η3He, has been investigated in the near-threshold region. The experiment was performed at the Glasgow tagged photon facility of the Mainz MAMI accelerator with the combined Crystal Ball – TAPS detector. Angular distributions and the total cross section were measured using the η→γγ and η→3π0→6γ decay channels. The observed extremely sharp rise of the cross section at threshold and the behavior of the angular distributions are evidence for a strong η3He final state interaction, pointing to the existence of a resonant state. The search for further evidence of this state in the excitation function of π0-proton back-to-back emission in the γ3He→π0pX reaction revealed a very complicated structure of the background and could not support previous conclusions