AdequaÃÃo da metodologia do teste de tetrazÃlio para avaliaÃÃo da viabilidade de sementes de cafà no armazenamento / Adaptation of the methodology of the tetrazolium test to assess the viability of coffee seeds during storage

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Germination of coffee seeds occurs in a slow and uneven way, making it difficult to obtain results of quality evaluation of lots in time for the propagation. One of the factors that delay germination is the presence of parchment that acts as a physical barrier to water and gases entrance. The tetrazolium test is an alternative for fast evaluation of seeds viability and has been adopted for the commercialization of this specie. The research was conducted in two phases aiming to adequate the methodology of the tetrazolium test, to reduce the pre-conditioning time of seeds and time to conduct the test. In the first phase we compared the use of sodium hypochlorite (200 ml NaCl 5%), in removing the parchment, with manual removal; and seeds imbibition time (36 and 48 hours) for extraction of the embryo in four lots of five coffee cultivars with variable quality and moisture content. In the second phase it was compared the manual removal of the parchment with the removal with sodium hypochlorite (200 ml NaCl 5%) in seeds of five coffee cultivars stored for 6 months. Besides the tetrazolium test, it was evaluated germination and determined the initial moisture of the lots of seed, at every 30 days during the storage period. The results of viability by tetrazolium test were compared with those from germination. We conclude that the use of sodium hypochlorite at a concentration of 5% for 6 hours of imbibition is not effective for removing the parchment and affects negatively the results of the tetrazolium test in coffee seeds with moisture content below 25%. The imbibition period of coffee seeds for 48 hours in the preparation phase, for the realization of the tetrazolium test, facilitates embryos extraction, without affecting the test results. The tetrazolium test in coffee seeds with different moisture and deterioration levels must be performed with the manual removal of the parchment.

ASSUNTO(S)

fitotecnia coffee tetrazolium test seeds teste de tetrazÃlio cafà sementes

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