ISHS Acta Horticulturae 658: I International Symposium on Rootstocks for Deciduous Fruit Tree Species
FLORAL MORPHOLOGY AND POLLEN VIABILITY OF THE 'FORASTERO' CULTIVAR [PRUNUS PERSICA (L.) BATSCH], AS MODIFIED BY THE ROOTSTOCK |
| Authors: | S. Radice, M. Ontivero, A. Andorno, S. Dessy |
| Keywords: | peach, stamen number, pistil length, floral index |
| Abstract:
Differences in the viability of the pollen and in the morphology of the peach flowers of the "Forastero" peach were observed when this cultivar was grafted onto different rootstocks. The propagation of the rootstocks compared was obtained from seeds (Cuaresmillo and GF 305), rooting of cuttings (Brompton, BrM; Ferdor-Julior, FJM; GF 655/2, GFM; and Mr.S 2/5, Mr.SM) and from micropropagated plants (Ferdor-Julior, FJm; GF 655/2, GFm; and Mr.S 2/5, Mr.Sm). The number of anthers observed were significantly different among "Forastero" flowers grown on GFm (44 anthers) and FJm and Cuaresmillo in San Pedro orchards (41 and 40 anthers, respectively). Differences in this character were not observed among "Forastero" flowers grown on the rootstock Cuaresmillo, in the two orchards tested. The greatest total pistil length was observed when "Forastero" flowers were grown on GF 305 (14.7 mm). It was significantly higher than observed on all the other scion-rootstock combinations, except for BrM. Only in this character, did Cuaresmillo induce significant differences in the "Forastero" flowers collected from the two orchards tested (9.6 and 12.6 mm for San Pedro and Chascomús, respectively). W All floral indexes obtained were superior to the average usually observed with peach. The lowest value in floral index was 2.81, corresponding to "Forastero" flowers grown on GF 305. Rootstocks GFM (3.88), FJm (3.91) and Mr.SM (3.94) promoted significantly smaller floral indices in comparison with FJM (4.8). FJM, Cuaresmillo (San Pedro-orchard), Mr.Sm and Mr.SM rootstocks induced the greatest viability of pollen grains on "Forastero" flowers (35%, 34%, 34% and 32%, respectively). The diameter of pollen grains varied between 30 and 35 m for all the scion-rootstock combinations. The biggest diameter was observed in "Forastero" flowers grown on GFm. This value was significantly higher than that observed for Cuaresmillo (San Pedro-orchard), FJM and FJm. This characteristic, together with a low percentage of viable pollen grains, a great number of anthers, short pistils and a high floral index, would indicate that the "Forastero" cultivar is a self-sterile variety and that the rootstock selected could modify these responses. | |
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