Adaptasi dan ketenggangan genotipe padi terhadap defisiensi fosfor di tanah sawah
ABSTRACT
ABD. AZlZ SYARIF. Adaptation and Tolerance of Rice Genotypes to
Phosphorus Deficiency in Paddy soil. Supervised by DIDY SOPANDIE, M. A.
CHOZIN, TRIKOESOEMANMGTYAS, KOMARUDDM IDRIS, and
SUWARNO.
Phosphorus deficiency is one of the constraints in rice production in
Indonesia, affecting about 1.27 miilion hectares of lowland (paddy) rice field.
The use of tolerant genotype to low phosphorus (deficient) soil has been believed
to be a sound approach to ease the problem. However, tailoring tolerant and high
yielding varieties requires identification of tolerant genotypes used as parent
material. Information on the mechanisms as well as the characters related to the
tolerance will be advantageous for accurate parental selection.
A research consisting of five experiments has k e n performed to evaluate
the variability of low P tolerance among rice gennplasm and to identify to tolerant
genotypes as well as the mechanisms and plant characters underlying the
tolerance. The results showed that there was phenotypic and genotypic variability
of low P tolerance among germplasm evaluated. Fourteen genotypes have been
identified as highly tolerant based on relative shad dryweight and 28 genotypes
based on relative tillering ability. Tolerant genotypes showed higher phosphorus
uptake and internal use eficiency than those of sensitive genotypes, indicating
both external and internal eficiency.
The mechanisms for high P uptake on low P soil among tolerant genotypes varied,
ranging from high root formation (hence soil interception), increased organic
acids exudation, and high root affinity for P. However, one genotype (Gadih Ani2 ) showed the three mechanisms. Field tolerance was correlated with plant and
root dryweight, plant P content and utilization efficiency under low (0.5 ppm) P
medium concentration. These characten can be used as criteria in selection for
low P tolerance. Some parameters, namely ratio of root-shoot dry weight, ratio of
root-shoot phosphorus content and concentration, phosphorus eficiency ratio and
utilization, and the longest root length increased with the decreased of phosphorus
availability in nutrient solution. These parameters were regarded as mechanisms
of adaptation of rice plant to low P. However, they were not consistent with the
tolerance to low P in paddy soil.
ABD. AZlZ SYARIF. Adaptation and Tolerance of Rice Genotypes to
Phosphorus Deficiency in Paddy soil. Supervised by DIDY SOPANDIE, M. A.
CHOZIN, TRIKOESOEMANMGTYAS, KOMARUDDM IDRIS, and
SUWARNO.
Phosphorus deficiency is one of the constraints in rice production in
Indonesia, affecting about 1.27 miilion hectares of lowland (paddy) rice field.
The use of tolerant genotype to low phosphorus (deficient) soil has been believed
to be a sound approach to ease the problem. However, tailoring tolerant and high
yielding varieties requires identification of tolerant genotypes used as parent
material. Information on the mechanisms as well as the characters related to the
tolerance will be advantageous for accurate parental selection.
A research consisting of five experiments has k e n performed to evaluate
the variability of low P tolerance among rice gennplasm and to identify to tolerant
genotypes as well as the mechanisms and plant characters underlying the
tolerance. The results showed that there was phenotypic and genotypic variability
of low P tolerance among germplasm evaluated. Fourteen genotypes have been
identified as highly tolerant based on relative shad dryweight and 28 genotypes
based on relative tillering ability. Tolerant genotypes showed higher phosphorus
uptake and internal use eficiency than those of sensitive genotypes, indicating
both external and internal eficiency.
The mechanisms for high P uptake on low P soil among tolerant genotypes varied,
ranging from high root formation (hence soil interception), increased organic
acids exudation, and high root affinity for P. However, one genotype (Gadih Ani2 ) showed the three mechanisms. Field tolerance was correlated with plant and
root dryweight, plant P content and utilization efficiency under low (0.5 ppm) P
medium concentration. These characten can be used as criteria in selection for
low P tolerance. Some parameters, namely ratio of root-shoot dry weight, ratio of
root-shoot phosphorus content and concentration, phosphorus eficiency ratio and
utilization, and the longest root length increased with the decreased of phosphorus
availability in nutrient solution. These parameters were regarded as mechanisms
of adaptation of rice plant to low P. However, they were not consistent with the
tolerance to low P in paddy soil.