关键词: 寒地, 水稻, 插植苗数, 种植密度, 倒伏

Abstract: Unreasonable planting density often caused rice lodging and yield decreased. In order to avoid rice yield loss with unreasonable transplanting specifications， rice varieties with different tillering ability were used to study the effects of plant spacing， row spacing and number of seedlings per hole on rice yield and lodging properties. The results showed that the optimal transplanting specifications for more tillers variety Kongyu 131 were 13.3 cm for plant spacing， 24.0 cm for row spacing and 2 for basic seedlings per hill， and the expected yield per hectare was the highest. The optimal transplanting specifications for less tillers variety Longjing 21 were 10.0 cm for plant spacing， 24.0 cm for row spacing and 5 basic seedlings per hill， and the expected yield per hectare was the highest. For plant spacing， no significant yield difference was observed between 10.0 and 13.3 cm. The interaction among variety， plant spacing and number of seedlings per hole had significant effect on yield， but the interaction between variety and row spacing had no significant effect on yield. The interaction among plant spacing， row spacing and number of seedlings per hole had significant effect on yield， too. The main reason resulting in higher yield was that the higher number of total spikelet increased per unit area under the condition of appropriate seedling numbers， plant spacing and row spacing. When plant spacing and row spacing were too small or seedling numbers per hole was too much， 2nd internode lodging index for two rice varieties increased and resistance ability decreased. The main reason resulting in weaker lodging resistance was that stem diameter of 2nd internode became thinner， stem sheath dry weight， internode dry weight and stem wall dry weight became lower， internode crosscutting area became smaller， and stem physics properties became weaker. Therefore， different rice varieties in cold region should pay attention to choice proper plant spacing， row spacing and seedling numbers per hole， and make yield and lodging resistance coordinate at higher level.

Key words: cold region, rice, seedlings per hole, density, lodging