Gaps between farmer and attainable yields across rainfed sunflower growing regions of Argentina

HALL, A.; FEOLI, C.E.; INGARAMO, J.; BALZARINI, M.

FIELD CROPS RESEARCH

ELSEVIER SCIENCE BV

Año: 2012

0378-4290

Yield gaps between attainable (derived from comparative yield trial data) and farmer (derived from reporting district [county] data) yields were computed for 8 regions of Argentina in which sunflower is grown under rainfed conditions, using BLUE values for both variables estimated from 5 to 9 years of data per region. These gaps were statistically significant (p . 0.05) for all regions and ranged from 0.37 to 1.18 t ha-1 across regions, for a country average of 0.75 t ha-1 , equivalent to 41% of the mean country yield of 1.85 t ha-1. Individual field yields were available for 5 regions, and gaps estimated using this variable were smaller (but never nil) than reporting district gaps in 3 regions. Mean yields for the top decile of comparative yield trial data ranged from 3.2 to 4.2 t ha-1 across regions, and the highest yields for this decile in any of the years of record ranged from 3.9 to 4.8 t ha-1. A notable feature of reporting district, individual field, and yield trial data was their variability. At reporting district level within regions, contributions of spatial and temporal variability were roughly similar. The mean relative contribution of the trial effect to non-error variance exceeded 85 % across regions, dominating the contributions of genotype and of genotype by trial effects. We conclude that the magnitude of farmer/attainable yield gaps for this crop justifies further research into its causes aimed at reducing regional gaps, and that mean comparative yield trial data provides a good benchmark for attainable yields, of greater practical value than mean trial top decile yields or the highest recorded value for the last variable.