Influence of methods of post-harvest treatment of maize hybrid seeds on their quality and lon-gevity

Abstract

The results on the effects of the technological operations and methods of post-harvest treatment on the maize hybrid seed quality and longevity are presented. The operations and methods included drying of wet cobs to dry consistency, separation of seeds in the cleaning, calibration and gravimetric sorting modes as well as chemical treatment (advance pre-sowing and immediate pre-sowing treatments).

The new drying method was found to depend on the harvest moisture and the speed of water evaporation from cobs. At moisture of 20.3–41.0%, drying at the optimum temperature and rapid water release were more effective, as this mode prevented seeds from germination and suppressed any activity of microorganisms. The drying temperature should be 36–40ºC at moisture of 30–32% and 40–44ºC at moisture of 20–22%.

The optimal methods and modes of separation, which ensured high germinability and yield of maize hybrid seeds after long-term storage, were defined. For seeds intended for long-term storage, the cleaning rate should be at least 80%, and fractions should be selected from this category by calibration on sieves with mesh diameters of 9, 8 and 7 mm. Gravimetric sorting increases the germinability and yield of hybrid seeds, especially of those that formed the smallest fraction (in our experiments, it came from the separation sieve with a mesh diameter of 6-5.5 mm depending on the hybrid).

Chemical treatment – seed dressing is a mandatory operation in the storage and sowing technologies for maize hybrids. It was found that chemical treatment – dressing should be carried out immediately before sowing this crop, and untreated seeds should be stored.

It was proven that, provided the optimized methods and modes of post-harvest and pre-sowing treatment, the maize hybrids could be stored for 3–4 years, with the laboratory and field germinabilities as well as yield of seeds remaining at high levels.