Genotype differences in nutrient uptake and utilisation for grain yield production of rainfed lowland rice under fertilised and non-fertilised conditions
P. Inthapanya, P",sipaseuth,"sihavong et al., Genotype differences in nutrient uptake and utilisation for grain yield production of rainfed lowland rice under fertilised and non-fertilised conditions, FIELD CR RE, 65(1), 2000, pp. 57-68
A large number of rainfed lowland rice genotypes were grown under two ferti
liser conditions to identify whether a genotype's ability to extract more n
utrients or to use absorbed nutrients more efficiently to produce grain yie
ld was more important in determining genotypic variation in grain yield. Fr
om the yield responses of lines to fertiliser application, 16 contrasting l
ines were selected, and dry matter and nutrient (N, P and K) contents were
determined for grain and straw separately for crops grown under non-fertili
sed and fertilised (60-13-16 N-P-K kg ha(-1)) conditions at three locations
in Laos.
There were significant effects of both genotype and genotype-by-fertiliser
interaction for grain yield, which were closely associated with total N and
P content at maturity. There was, however, also significant genotypic vari
ation in nutrient-use efficiency (grain yield per unit nutrient absorbed),
and this also contributed to the genotypic variation for grain yield. There
was a large effect of genotype and a smaller effect of genotype-by-locatio
n interaction for nitrogen-use efficiency for grain yield. Nitrogen-use eff
iciency was negatively correlated with grain N concentration at two of the
three locations. Both N- and P-use efficiency were consistent across fertil
iser levels, and hence are likely to be used as selection criteria. The wor
k also indicates that genotypes with high harvest index (HI) are likely to
perform well in different fertility conditions. (C) 2000 Elsevier Science B
.V. All rights reserved.