Qualidade de sementes de quiabeiro (Abelmoschus esculentus (L.) Moench.) submetidas à termoterapia

Abstract

The okra [Abelmoschus esculentus (L.) Moench.], Is a vegetable belonging to the botanical family Malvácea, and has great popularity in the northeastern and southeastern regions of Brazil, usually marketed in free fairs throughout the year. Produced by agroecological-based farmers, it is, in some cases, the main source of family income, and is considered a rustic, heat tolerant plant and does not require much technology for its cultivation, besides being produced in climatic regions hot all year round. The sanitary and physiological quality of the seeds is of great importance and deserves due attention due to the negative impacts that the association of pathogens with seeds generates in agriculture and in the market of agricultural products. Thermotherapy becomes a viable alternative to control pathogens in seeds only with the use of heat in a given time frame. The objective of this work was to evaluate the influence of thermotherapy on the quality of okra seeds. The treatments used were: T1 = water at 60 ° C for 5 min, T2 = water at 60 ° C for 10 minutes, T3 = water at 60 ° C for 15 minutes, T4 = water at 65 ° C for 5 minutes, T5 = water at 65 ° C for 10 minutes, T6 = water at 65 ° C for 15 minutes, T7 = water at 70 ° C for 5 minutes, T8 = water at 70 ° C for 10 minutes, T9 = water at 70 ° C for 15 minutes and T10 = Witness. The variables analyzed were percentage of germination (GE), percentage of emergence (EM), rate of germination (IVG), rate of emergence (IR), first count (PC), percentage of hard seeds (CPA), root length (CRA), seedling length (CPL), dry shoot mass (MSPA), root dry mass (MSRA) ), total dry mass (MST), stem diameter (DC). The seeds were examined individually with the aid of a stereomicroscope, by the growth of fungal colonies to confirm the identity of fungi at the genus level. In the germination test, four samples and three replicates of 25 seeds distributed in Germitest paper, moistened with ADE at 2.5 times the dry paper weight, were used in the incubation room at 25 ºC for each thermotherapeutic treatment. For the seedling emergence test in the greenhouse, four subsamples of 50 seeds were used for each treatment, with washed and sterilized sand being used, and sowing in two-cell multicellular trays with dimensions of 67cm x 34cm x 5cm. It was observed the occurrence of mycoflora represented by the fungi Fusarium sp. (32%), Cladosporium sp. (22%), Alternaria sp. (36.5%), Aspergillus sp. (5%), Nigrospora sp. (1%), Rhizopus sp. (0.5%), Ascochyta sp. (2.5%) and Monilia sp. (0.5%). The treatment that presented the best performance in obtaining quality of the okra seeds was that of 65 ° C to 10 minutes of immersion.