However the association between yield and length is still strong.
If anything,
length can be a positive yield component if all other yield components are held constant (Coyle and Smith, 1997), so there should not be a negative association unless longer fibres’ require more energy to sustain more turgor.
For AUS breeding material, we believe we now have a number of lines with length at our target of 31.8 mm and good yield (Fig. 1) and that result may be an indirect way of concluding the negative association is linkage (Meredith and Bridge, 1971 and Smith and Coyle, 1997).
In addition, the observation that the negative association between yield and fibre length is dependent on the genetic population (Constable and Bange, 2007) would support the linkage theory.