Efficiency of check-plot designs in unreplicated field trials |
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Authors: | S Chandra |
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Institution: | (1) Institute für Angewandte Mathematik und Statistik, Universität Hohenheim, D-70593 Stuttgart, Germany;(2) Present address: Department of Mathematics and Statistics, G.B. Pant University, 263 145 Pantnagar, India |
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Abstract: | Check-plot designs have a lower selection intensity than unreplicated non-check-plot designs if both the number of test lines to be selected (s) and of total plots in the trial (N) are kept constant. For a check-plot design to be more efficient, local control must effectively reduce the plot error variance and increase heritability to such a level that it compensates for the corresponding loss in selection intensity and makes the expected gain from selection at least equal to that in the non-check-plot design. To realize this goal, the required minimum reduction in plot error variance in a checkplot design (relative to that in a non-check-plot design) depends on (1) check-plot frequencyf
c
, (2) fractionk = s/N, and (3) ratiow
0=
0
2
/
g
2
of non-check-plot design plot error variance
0
2
to genetic variance
g
2
among test lines. Lowerw
0 and higherf
c
andk are found to require a relatively higher reduction in plot error variance in check-plot designs. A condition is derived to show when a check-plot design may never be more efficient. |
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Keywords: | Check-plot designs Efficiency Expected gain from selection Local control Unreplicated field trials |
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