Labor scarcity requires double-season rice to be planted by direct seeding as an alternative to transplant-ing.Only ultrashort-duration varieties can be used in direct-seeded,double-season rice(DSD)in central China where thermal time is limited.Whether ultrashort-duration varieties grown in DSD can be as pro-ductive and efficient in nitrogen(N)use as transplanted double-season rice(TPD)remains unclear.Field experiments were conducted in Hubei province,central China with two establishment methods(DSD,TPD)and three N rates in the early and late seasons of 2017 and 2018.Nitrogen treatments included zero-N control(NO),total N rate of 60 kg N ha-1 with equal splits at basal,midtillering,and panicle ini-tiation(N1),and weekly N application at 15 kg ha-1 from seeding/transplanting to heading(N2).Both early-and late-season rice under DSD matured within 95 days,on average 9 days shorter than rice under TPD.The grain yield of DSD was comparable to or higher than that of TDP in both seasons,although the daily yield was significantly higher under DSD than under TDP.Before heading,DSD had higher leaf area,stem number,intercepted radiation,and radiation use efficiency than TPD,which compensated for the negative effect of short growth duration on biomass production.Total dry weight and harvest index under DSD were comparable to or higher than those under TDP.In general,the recovery efficiency of fertilizer-N under DSD was higher than that under TPD,but the reverse was true for physiological N use efficiency.Thus,there was no significant difference in agronomic N use efficiency between DSD and TPD.These results suggested that DSD with ultrashort-duration varieties is a promising alternative to TPD in central China for maintaining high grain yield and N fertilizer use efficiency with less labor input.

Le Xu;Shen Yuan;Xinyu Wang;Zhifeng Chen;Xiaoxiao Li;Jing Cao;Fei Wang;Jianliang Huang;Shaobing Peng

National Key Laboratory of Crop Genetic Improvement,Hubei Hongshan Laboratory,MARA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River,College of Plant Science and Technology,Huazhong Agricultural University,Wuhan 430070,Hubei,China

作物学报（英文版）

[1]Le Xu;Shen Yuan;Xinyu Wang;Zhifeng Chen;Xiaoxiao Li;Jing Cao;Fei Wang;Jianliang Huang;Shaobing Peng-.Comparison of yield performance between direct-seeded and transplanted double-season rice using ultrashort-duration varieties in central China)[J].作物学报（英文版）,2022(02):515-523

midtillering

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