Híbridos entre Coffea e Psilanthopsis

Abstract

Reviewing the taxonomy of the genus Coffea Chevalier stablished the new genus Psilanthopsis with a single species P. kapakata. This species had previously been classified as Coffea kapakata by Hirschfeldt and is native to Angola, Africa. A few representatives of P. kapakata were received in Campinas in 1953 from U. S. Department of Agriculture after strict quarantine inspection. In the 1955 and 1956 seasons several artificial pollinations were undertaken of the species Coffea arabica (2n = 44) and diploid species (2n = 22) of Coffea as C. canephora, C. eugenioides and C. Dewevrei with P. kapakata as male parent. The number of pollinated flowers and the number of fruits and seeds developed as well as the number of seedlings obtained, are mentioned in table I. The percentage of fruits derived from crosses of Coffea arabica, C. canephora, C. eugenioides and C. Dewevrei with P. kapakata were respectively 55, 17, 13 and 2%. However, the percentage of seedlings resulting from the normal hybrid seeds were 8, 35, 4.8 and 0%, respectively. In spite of the larger number of seeds derived from crosses with varieties of C. arabica (194), only 16 seedlings were obtained, while relatively larger number of these were developed from crosses of P. kapakata with C. eugenioides and C. canephora. A morphological study was undertaken of one seedling from each successful cross, in order to compare the hybrids with their respective parents. The most vigorous hybrids have resulted from crosses with C. canephora and C. eugenioides. The hybrids with C. arabica var. laurina indicated that Psilanthopsis kapakata probably carries the allele Lr. The leaf of the hybrids are most frequently intermediate in size as compared to the leaves of their parents, except in the hybrid with laurina which possesses larger leaves. The bronze color of the young leaves of C. arabica var. typica is almost dominant in relation to the red ones of Psilanthopsis kapakata, whereas in the hybrid with laurina, which has green young leaves, the color is light bronze. The bronze young leaf color of C. canephora is dominant, while the bronze color of C. eugenioides is recessive to the red color of P. kapakata. In all hybrids the reddish color of the young stem of P. kapakata seems to be dominant. One flowered inflorescence, frequently found in P. kapakata is recessive in all crosses. The rather developed sepals of P. kapakata are present in hybrids with C. arabica var. typiea, C. arabica var. laurina and C. eugenioides. In the hybrid with C. canephora the sepals are almost unnoticeable. An inspection of the surface of the young fruit indicates that the presence of developed ridges of the fruits of P. kapakata is present in all hybrids with variable intensity. The percentage of successful crosses of Psilanthopsis kapakata with the Coffea species here mentioned is of the same order as in crosses among species of the genus Coffea. Due to the already complex nature of the genus Coffea and based on the results here presented, it is proposed to revert the species Psilanthopsis kapakata to the genus Coffea - Coffea kapakata Hirschfeldt, sub-section Mozambicoffea.