Genetic and agronomic contributions to yield gains: A case study for wheat
Bell, M.A.
Genetic and agronomic contributions to yield gains: A case study for wheat - 1995 - Printed
Peer-review: Yes - Open Access: Yes|http://science.thomsonreuters.com/cgi-bin/jrnlst/jlresults.cgi?PC=MASTER&ISSN=0378-4290
Genetic and agronomic contributions to yield gains for wheat (Triticum aestivum L.) in the Yaqui Valley of northwest Mexico were estimated for the period from 1968-1990. Five problems associated with estimating sources of yield gains were considered, namely: (1) adjusting yield gains for variation in weather over the study period; (2) considering annual cultivar-by-weather interactions, which are potentially problematic when relative yields of cultivars are generated over only part of the study period; (3) overestimating relative yields of cultivars if the check cultivar(s) become susceptible to disease; (4) ensuring that yields as estimated from research station trials represent cultivar performance under farmers' conditions; and (5) allowing for cultivar-by-management interactions. With these factors considered, 28% of the weather-adjusted yield gain of 103 kg ha(-1) y(-1) was attributed to genetic gain (i.e., cultivar improvement). If the yield gains had not been adjusted for annual weather variation, genetic gain would have been overestimated at 50%. By contrast, 48% of the gain was attributed to increased use of N fertilizer, driven at least in part by a decline in N prices; no N-by-cultivar interactions were apparent. The remainder of the yield gap (24%) could not be attributed to specific factors, although P application rates increased over time, and negative deviations from linearity were associated with years having greater than normal rainfall in November and December (a phenomenon which can delay sowing and/or reduce crop stand). In addition to identifying factors contributing to yield gains, technologies that have contributed benefits not measured by yield are discussed
English
Agronomic characters
Environmental factors
Genetic gain
Mexico
Research projects
Yield factors
Triticum aestivum
Wheat
Yields
CIMMYT
Genetic and agronomic contributions to yield gains: A case study for wheat - 1995 - Printed
Peer-review: Yes - Open Access: Yes|http://science.thomsonreuters.com/cgi-bin/jrnlst/jlresults.cgi?PC=MASTER&ISSN=0378-4290
Genetic and agronomic contributions to yield gains for wheat (Triticum aestivum L.) in the Yaqui Valley of northwest Mexico were estimated for the period from 1968-1990. Five problems associated with estimating sources of yield gains were considered, namely: (1) adjusting yield gains for variation in weather over the study period; (2) considering annual cultivar-by-weather interactions, which are potentially problematic when relative yields of cultivars are generated over only part of the study period; (3) overestimating relative yields of cultivars if the check cultivar(s) become susceptible to disease; (4) ensuring that yields as estimated from research station trials represent cultivar performance under farmers' conditions; and (5) allowing for cultivar-by-management interactions. With these factors considered, 28% of the weather-adjusted yield gain of 103 kg ha(-1) y(-1) was attributed to genetic gain (i.e., cultivar improvement). If the yield gains had not been adjusted for annual weather variation, genetic gain would have been overestimated at 50%. By contrast, 48% of the gain was attributed to increased use of N fertilizer, driven at least in part by a decline in N prices; no N-by-cultivar interactions were apparent. The remainder of the yield gap (24%) could not be attributed to specific factors, although P application rates increased over time, and negative deviations from linearity were associated with years having greater than normal rainfall in November and December (a phenomenon which can delay sowing and/or reduce crop stand). In addition to identifying factors contributing to yield gains, technologies that have contributed benefits not measured by yield are discussed
English
Agronomic characters
Environmental factors
Genetic gain
Mexico
Research projects
Yield factors
Triticum aestivum
Wheat
Yields
CIMMYT