P. Inthapanya, P",sipaseuth,"sihavong et al., Genotypic performance under fertilised and non-fertilised conditions in rainfed lowland rice, FIELD CR RE, 65(1), 2000, pp. 1-14
The rate of fertiliser application to rainfed lowland rice is commonly low
while selection in breeding programs is conducted under well-fertilised con
ditions. The appropriateness of applying fertiliser in a rainfed lowland ri
ce breeding program at a rate above the average farmers' rate was examined
in Laos. Experiments were conducted at three locations in 2 years using 72-
60 genotypes most of which were typical materials used in the Lao breeding
program. The fertiliser rates were nil and 60N : 13P : 16K kg ha(-1).
The effect of fertiliser application was significant in most experiments, b
ut the response to fertiliser depended on location, There was often signifi
cant genotype-by-environment interaction for grain yield in individual expe
riments. There was also significant correlation for grain yield between fer
tilised and non-fertilised conditions, with coefficients of determination (
R-2) of 0.45 and 0.54 in the 2 years, for combined results of three locatio
ns. Combined analyses of grain yield from three locations indicate that for
either year the variance component for the genotype-by-fertiliser interact
ion was smaller than for genotype. The coefficient of variation for grain y
ield was often smaller under fertilised compared with non-fertilised condit
ions. These findings as well as the rapidly increasing use of fertiliser ju
stify the level of fertiliser currently applied in the Lao breeding program
, The significant genotype-by-location interaction requires that for an eff
ective breeding program, locations be selected to represent farmers' fields
. (C) 2000 Elsevier Science B.V. All rights reserved.