Qualidade de sementes de trigo colhidas com diferentes teores de água e armazenadas em sistema convencional e hermético

Abstract

Wheat is one of the main cereal food consumed in the world, being one of the most important crops for food security. The harvesting time and grain storage, influence the physical, chemical, physiological and sanitary quality of wheat seeds (Triticum aestivum). In this way, the study aimed to evaluate the physical and sanitary quality, as well as the physiological performance of wheat seeds as a function of different grain moisture in the harvest with subsequent storage in a hermetic and conventional system. To do so, wheat seeds, cultivar BRS Parudo, was sowed. It was used a completely randomized experimental design, arranged in factor 5x3x2 (storage time x harvesting grain moisture x storage system), with four replications. The data obtained were submitted to variance analysis, with subsequent means comparison test (Tukey HSD Test) or regression analysis. The harvest was realized when the seeds reached 28.6, 18.5 e 12.9% grain moisture, following by drying at 38 °C in a forced-air-circulation oven until the water content reached approximately 13%. Subsequently, the seeds were stored for 240 days under two systems, hermetic (PET bottles) and conventional (Kraft paper bags) at room temperature. The evaluation of the physical and sanitary quality, besides the physiological performance of the seeds, was carried out immediately after the harvest and, later, every 60 days by determination of the grain moisture, thousand seed weight, hectoliter weight, electrical conductivity, sanitary test (Blotter Test), germination test, first germination count, germination speed index, accelerated aging test, cold test, shoot length and dry matter of seedlings. The physical quality of the wheat seeds reduced over the storage time, regardless of the water content in the harvest and the storage system; Fusarium spp. Incidence and field fungi reduced over time of storage, while Aspergillus spp. and Penicillium spp. incidence increased, regardless of the water content in the harvest and the storage system. Wheat seeds germination, stored under a hermetic system, increased up to 180 days of storage due to the dormancy breaking process, with subsequent fall of the observed values, while those stored under conventional system showed a linear decrease germination throughout the storage. The hermetic system provided an increase in seed vigor up to 120 days of storage, and after this period there was a reduction of the observed values. The conventional system promoted the linear reduction of seed vigor throughout the storage, except for the results demonstrated in the tests of first count of germination and rate of germination, which showed an increase up to 60 days of storage. The hermetic system provided better physical and sanitary quality and better physiological performance to the seeds compared to conventional at the end of the storage period; and, the harvest delay negatively influenced the physical, sanitary quality and the physiological performance of the seeds throughout the storage.