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美国棉花品种的改良趋势①产量在过去５０年的时间里，通过品种改良，美国棉花产量每年以７～１０磅·ｈｍ－２的速度递增。这一进展很大程度上归因于更多的生物量分配到棉铃，同期的收获指数从４５％提高到６０％。就产量构成因素而言，从本世纪初到８０年代，美国育成的...
Improved trend of cotton varieties in the United States ① Yield Over the past 50 years, cotton varieties in the United States have been increasing by 7-10 lb · hm-2 annually through variety improvement. Much of this progress is attributed to the more biomass allocated to bollworms and the harvest index from 45% to 60% over the same period. From the beginning of this century to the 1980s, the United States bred ...