Abstract: The differences of cotton boll position in the same plant result in differences in yield components such as boil weight, seed index and lint percentage and in fiber physical characteristics such as fiber length, strength and fineness.These differences show some read.larities.The first boil position of each fruiting branch on the same plant has the highest boll-forming ability and can produce the largest bolts.Boil weight and lint percentage change in parabolical curves with rise of fruiting branch nodes.Boll weight and lint percentage sharply rise and fall espectively with extension of boil position on the same finiting branch: fiber physical characteristics change as follows: Fiber fineness change gradually from fineness to coarseness and then from coarseness to fineness,fiber strength, gradually from strongness to weakness, but fracture length does not change with rise of fruiting branch node on the same plant.Fiber fineness and length increased and fiber strength decreased with extension of boil position on the same fruiting branch.

Key words: Upland cotton, Boll position, Yield characters, Fiber quality, Differences on the same plant

CLC Number: 

• S515.01