Cotton Breeding for Fiber Quality Improvement - Industrial Crops: Breeding for BioEnergy and Bioproducts - page 217

Fig. 10.5 The negative association between lint yield and fiber strength in 6-11 years of data from
Australia and the USA. R 2 values for multiple regressions were 0.35 ( P < 0.001) and 0.32

( P 0.05) for Australian and USA data, respectively (Reprinted from Clement et al. [ 138 ]. With

permission from Elsevier)

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quality from relatively poor values to base values or from base to premium values
would be similar, although different parents would be used.
Broad sense heritability estimates for fiber quality are considered moderate to
highly heritable ( > 0.50) [ 27 ]. This is desirable for breeding, indicating the potential
inheritance of the trait and predicting gain from selection. Genetic variability for
the trait of interest is an essential component for gains to be made, and there is
ample evidence for fiber quality improvement. Western US Acala cottons, eastern
US PeeDee cottons, and transgressive segregants have been shown to be sources of
improved fiber length and strength [ 59 , 141 , 142 ]. Interestingly, both Acala and
PeeDee pedigrees involve introgressions of both G. barbadense and diploids
[ 33 ]. Smith et al. [ 143 ] reported G. hirsutum breeding lines with substantially
improved fiber length (Upland Extra Long Staple) with little or no recent introgres-
sion from G. barbadense . New cotton lines have also been generated with the aid of
mutagenesis which had 8-9 % greater fiber length than its original cultivar [ 144 ].
Meredith and Bridge [ 45 ] suggest that any method that allows hybridization and
recombination should assist in breaking the negative association between yield and
quality, provided that populations are large enough, but this is a significant con-
straint in a number of programs. Clement et al. [ 138 ] concluded that recurrent