Uma nova forma de Coffea

In the past 18 years coffee breeding investigations by the Genetics Division of the Instituto Agronômico have been largeiy confined to the species C. arabica because it is the species that produces coffee of the best marketable qualities. Coffee cultivation in depleted soils requires the use of very vigorous plants. Vigorous plant growth is more frequently found in some diploid species of Coffea. Artificial hybridization of these diploid species with the tetraploid species C. arabica has been tried in several of the Institutes' Experiment Stations where breeding work on coffee is underway. Small scale breeding tests have also been carried out at Campinas for many years in which attempts have been made to combine the favorable qualities of plant vigor, as found in C. canephora and C. Dewevrei, with the good "cup qualities" of C. arabica. The results of these initial investigations indicate, however, that the obtaining of an interspecific hybrid suitable for use in the areas with depleted soils, would be very slow process. The accidental finding of a new type of coffee on a plantation in Viradouro County, which, with few exceptions, offers the desired combinations of characters, is of special interest. It is the purpose in this paper, to describe the characteristics of the new type of. coffee. The new type is believed to be a natural hybrid between C. arabica and C. Dewevrei. It has 44 chromosomes, is extremely vigorous and productive, and its seeds produce a beverage of reasonably good quality. Its principal defect is its almost complete self-sterility. Detailed cytological observations have been made on the meiotic behavior of the chromosomes of the original new type coffee plant and several of its interespecific hybrids. These studies suggest the hypothesis that this new type coffee plant has 22 chromosomes of C. arabica (normal haploid number of this species) and 22 chromosomes (diploid number) of C. Dewevrei. A large number of crosses have been made between this new type of coffee and different genotypes of C. arabica (nana ; prpr ; FsFs ; lelr ; momo ; MgMg ; ErEr ; C-; CtCt ; cece ; etc.). The results of these studies have furnished preliminary information on the genetic constitution of the new coffee type. It is heterozygous with respect to the genes which control its principal morphological characters ; it has various alleles of the known genes of C. arabica, plants of the F1 generation and back-crosses with C. arabica show a predominance of the principal characters of the new type coffee plant. Self-sterility remains dominant in the progeny of the backcrosses but some plants have been found that have a reasonable degree of self-fertility. This new type of coffee has a special value as a basis for the breeding and developing of new coffee types. It is also being tested in mixed plantings where it is established as a clone and planted in alternate rows of plants of C. arabica var. bourbon that serve as sources of pollen. The finding of this new type of coffee greatly facilitates the possible development of still other coffee types that may prove to be even more satisfactory for use on depleted soils.