Effects of Seedling Age on Seedling Quality and Yield of Mechanical Transplanted Double-season Early Rice in the Area of Yangtze River of Anhui Province

[Objective] The aim was to make sure the optimal transplanting period for mechanical transplanted double-season early rice.[Method]In order to study the effects of seedling age on quality and yield of mechanical transplanted double-season early rice,a field experiment was conducted with four seedling age trements( 20,24,28 and 32 days) using a high yield early rice Zhongzao15. [Result] With the extension of the seedling age,the seedling quality and seedling state were improved. Meanwhile,the total amount of spikelet and the yield were increased significantly within 28 d. But the number of white roots,root / shoot ratio and seedling quality were decreased when seedling age extened 28 d. The decrease of the height uniformity and plant regeneration also lead to seedling state became worse. Finally,the yield was decreased significantly. [Conclusion] Seedling age ranged from 24 d to 28 d were suitable for mechanical transplanted double-season early rice in the area of Yangtze river of Anhui province and seedling age of 28 d was the best.