The interaction between breeding and crop management in improved
cotton yield
New cultivars, improved management and their interactions are key drivers of yield progress in field
crops. This study examined the contribution of these factors to cotton yield increase in Australia with
the adoption of 23 key locally bred cultivars developed by the Commonwealth Scientific and Industrial
Research Organisation (CSIRO) cotton breeding programme up to 2006. A lint yield dataset of advanced
line trials from 1980 to 2009 (325 experiments) was analysed by a linear mixed model when split into
two 15-year periods. These trials were conducted at up to 15 irrigated sites each year, and best linear
unbiased estimates (BLUEs) of cultivar yield and two long-term controls (Deltapine 16 and Namcala)
were used to assess yield trend. Lint yield increased progressively as new cultivars were released and
yield gain was almost three times as high in the recent 15-year period as the early one (18.3 versus
7.0 kg ha−1 year−1). This gain tended to be greater in cooler than warmer regions, despite lower yield in
the cool. The most recent cultivars also showed improved stability. When pairs of cultivars derived from
intra-cultivar selection were compared, reselected ones outyielded their parents and with higher stability.
The increased cultivar yield and the reduction of genotype
×
region and genotype
×
year interaction were
the main reasons behind the ongoing improved yield and stability of these released cultivars. Using yield
estimates of 10 cultivars tested in both time periods, yield gain was found to be attributed by cultivar,
i.e. genetics (48%), management (28%) and cultivar
×
management (24%). There was evidence for cultivar
resistance to Verticillium wilt being a strong component of the cultivar
×
management interaction. It
was concluded that cotton yield progress in Australia was achieved mostly through exploiting genetic
variation and genotypic response to modern management.
The interaction between breeding and crop management in improvedcotton yieldNew cultivars, improved management and their interactions are key drivers of yield progress in fieldcrops. This study examined the contribution of these factors to cotton yield increase in Australia withthe adoption of 23 key locally bred cultivars developed by the Commonwealth Scientific and IndustrialResearch Organisation (CSIRO) cotton breeding programme up to 2006. A lint yield dataset of advancedline trials from 1980 to 2009 (325 experiments) was analysed by a linear mixed model when split intotwo 15-year periods. These trials were conducted at up to 15 irrigated sites each year, and best linearunbiased estimates (BLUEs) of cultivar yield and two long-term controls (Deltapine 16 and Namcala)were used to assess yield trend. Lint yield increased progressively as new cultivars were released andyield gain was almost three times as high in the recent 15-year period as the early one (18.3 versus7.0 kg ha−1 year−1). This gain tended to be greater in cooler than warmer regions, despite lower yield inthe cool. The most recent cultivars also showed improved stability. When pairs of cultivars derived fromintra-cultivar selection were compared, reselected ones outyielded their parents and with higher stability.The increased cultivar yield and the reduction of genotype×region and genotype×year interaction werethe main reasons behind the ongoing improved yield and stability of these released cultivars. Using yield
estimates of 10 cultivars tested in both time periods, yield gain was found to be attributed by cultivar,
i.e. genetics (48%), management (28%) and cultivar
×
management (24%). There was evidence for cultivar
resistance to Verticillium wilt being a strong component of the cultivar
×
management interaction. It
was concluded that cotton yield progress in Australia was achieved mostly through exploiting genetic
variation and genotypic response to modern management.
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