Abstract:

Mechanical harvesting has become the development direction of current sesame production. In view of the insufficient research on the germination of mechanically harvested seeds，this experiment used sesame seeds obtained by different methods at different harvest time to conduct studies on seed damage and germination characteristics. The results showed that the seed damage rate of mechanical harvesting（6.50%-12.50%）was significantly （p<0.05） higher than that of manual harvesting（1.00%）. With the delay of mechanical harvesting time，the seed damage rate gradually decreased. Mechanical harvesting at the maturity stage specified by the current standard led to easy seed mildew. Compared with mechanical harvesting，manual harvesting resulted in significantly higher germination rate，germination potential，germination index，vigor index，and fresh weight. The damage rate of manual harvesting showed a highly significant （p<0.01）negative correlation with all other indicators. Some damaged or mildewed seeds still possessed germination ability，and a few mildewed seeds even maintained normal vigor. The maturity stage defined by the current standard is not suitable for mechanical harvesting. The mechanical harvesting time should not be earlier than the stage when the top of the plant is still not dry and three-quarters of the capsules have dehisced，and it is better to harvest when the whole plant is dry. Given the impact of mechanical harvesting on seed germination and seedling growth，it is recommended to increase the seeding rate of varieties suitable for mechanical harvesting by 11% compared with traditional varieties. This study provides a theoretical basis for determining the optimal harvest time and seeding rate for sesame varieties suitable for mechanical harvesting.

Key words: sesame, mechanical harvesting, damage, germination rate, mildew