IFEVA   02662
INSTITUTO DE INVESTIGACIONES FISIOLOGICAS Y ECOLOGICAS VINCULADAS A LA AGRICULTURA
Unidad Ejecutora - UE
artículos
Título:
Global trends of rapeseed grain yield stability and rapeseed-to-wheat yield ratio in the last four decades
Autor/es:
RONDANINI D; GOMEZ N V; AGOSTI M B; MIRALLES DJ
Revista:
EUROPEAN JOURNAL OF AGRONOMY
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2012 vol. 1 p. 56 - 65
ISSN:
1161-0301
Resumen:
Increases in crop yields are important to ensure food supply for humanity. Global yield trends have been
analyzed considering public national average data, mainly for cereals but not for rapeseed. As rapeseed
and wheat compete for land in crop rotation, it is also important to know how the rapeseed-to-wheat yield
ratio is modified in different environments so as to make rapeseed an attractive alternative for farmers
around the world. The present study analyzed historical records of rapeseed from FAO determining yield
stability trends over the last 40 yr, as well as rapeseed competitiveness compared to wheat. Twelve
countries representing a wide range of environments and farming systems were taken into account.
Regressions were fitted to the rapeseed yield/time relationships and residuals of these regressions were
used to evaluate trends in yield stability. Results showed a global rapeseed yield gain of 27 kg ha−1 yr−1
along the past 40 yr, although fluctuating among decades. In relative terms to 1970, world rapeseed
yield increased 3.4% yr−1. Yield gain in different countries varied from 15 to 40 kg ha−1 yr−1, exhibiting
linear, bi- or tri-linear yield trends. Opposite yield trends were observed for Chile and the UK, with
sustained yield gain for the former and leveling off for the latter since the mid 1980s. This does not seem
to be related to the supply of environmental resources (both countries yielding >3000 kg ha−1). A high
variability was detected in national yields (0750 kg ha−1 or 060% of yield) and yield stability did not
increase over the last 40 yr in any country. Rapeseed and wheat yields, expressed in relative terms to
their values for 1970, increased in a similar proportion over the last four decades. Global rapeseed-towheat
ratio ranged 4060% over the last 40 yr, but rapeseed yields can increase up to 80100% with
respect to wheat in poor environments for wheat (4000 kg ha−1). It was concluded that rapeseed yields have increased steadily in
the last 40 yr in most studied countries, the yield gain was not accompanied by greater yield stability,
and rapeseed competitiveness compared to wheat is at least 4050% in environments with good supply
of resources