Álvaro Eleutério Da Silva
Published: 1990
Total Pages: 352
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Genotype screenin and selection for tolerance to low-phosfhorus stress conditions is an importan strategy for the development of cultivars for growing on soils low in available P. This study was conducted to adjust a screening methodologu to provid a stable, diffusion-limited low-P concentration during the vegetative growth of maize, to effectively select maize inbreds efficient in P acquisition and utilization and to provid information o the inheritance to low-P stress. Sand-alumina, a solid culture medium, which simulates a slow release, diffusion-limited P movement in soil solution was used to screen 20 mize inbreds known to be efficient in P uptake or accumulation and/or tolerant to aluminum toxicity. The selecte inbreds were used to obtain F1 hybrids and advanced generations to be evaluated in diallel mating schemes and generation means analyses for the inheritance studies. Low and high-P concentration levels were established (200 mM and 400mM, respectively) that provided a reproducible and diffusion-controlled availability of P to the plants at concentrations of 8-10 uM and 30-40 uM, respectively, of culture medium solution P at the time of transplanting. The procedure was also effective in providing low concentrations of P during the period of plant growth. Twenty-five days after transplanting was the best time to diffrentiate maize inbreds at the low P concentration. From 20 initial inbreds, 10 inibreds with similar dry weigts at high P and significantily different dry weights at low-P were selected (...).