Uso de sementes criopreservadas e cultivo protegido para a produção de mudas de Coffea arabica L.

Abstract

The propagation of arabica coffee is still predominantly carried out by seedlings produced from seed sowing, which present slow germination and low tolerance to desiccation and longevity. These characteristics make it difficult to produce seedlings in a climate season that is more appropriate to planting and establishing the crop. Thus, the proposal in these studies was to investigate the formation of coffee seedlings, at different times and environments, with seeds from different drying and storage treatments. Cryopreservation or storage in liquid nitrogen for an indefinite period of properly prepared seeds is a viable alternative to coffee. In that way, the objective in the first study was to investigate the formation of seedlings from cryopreserved seeds for six months, in two consecutive harvests. Seeds of Coffea arabica L., ‘Catuaí amarelo’ IAC 62 cultivar were harvested at the physiological maturity stage and submitted to four drying treatments: seeds dried in a small scale stationary dryer until reaching 12% and 32% hu midity and stored in a cold and dry room; seeds dried in saturated NaCl solution until they reached 17% humidity; and seeds dried on silica gel until reaching 17% humidity stored in liquid nitrogen. The seedlings were produced in the nursery, in plastic bags containing Tropstrato. The seeds used were freshly harvested or with six months of storage, those with 12 and 32% humidity were stored in a cold room and those with 17% humidity were stored in liquid nitrogen. Seeds with 32% and 12% of humidity stored in cold rooms and with 17% of humidity stored in liquid nitrogen, after silica gel drying, showed the same physiological performance. The use of Coffea arabica L. seeds cryopreserved and dried on silica gel is a viable alternative for the production of seedlings. In the second study was investigated the formation of coffee seedlings under protected cultivation under greenhouse conditions, a system successfully used for forest species. The objective with this study was to investigate the formation of Coffea arabica L. seedlings from seeds submitted to different drying and storage methodologies, including cryopreservation, in different crop year and seedling production sites. It was verified that coffee seeds with 32% humidity stored in cold room and cryopreserved seeds with 17% humidity had the same germination and vigor after six months of storage. The vegetative development of Coffea arabica L. seedlings in greenhouse was superior to the conventional nursery system in most evaluations.