QTLs underlying Rice Tolerance to Low-Potassium Stress in Rice Seedlings
- P. Wu ,
- J. J. Ni and
- A. C. Luo
Potassium is an important nutrient in plant growth and development of rice (Oryza sativa L.), but K availability may be seriously limited in developing countries. Genotypic variation in tolerance to Iow-K stress has been shown. This study was conducted to investigate the genetic basis for tolerance to low-K stress in rice and to identify the quantitative trait loci (QTLs) that provide this tolerance. On the basis of preliminary tests, seedlings of 123 double haploid (DH) lines and their parents (which differed in response to K supply) ‘IR64’, indica cultivar and ‘Azucena’, a Japonica variety, were grown in a hydroponic greenhouse study at adequate and at stress levels of K in August, 1995, at Zhejiang Agricultural University, Hangzhoo, China. Plants were sampled after 4 wk in culture solution and measurements were made for plant height, shoot and root dry matter, K concentration in plant tissue, K uptake, and K use efficiency. Relative changes of the parameters from K-sufficient to K-stress culture were calculated to evaluate the genotypic variation in tolerance to K-stress. IR64 was more tolerant to low-K stress than Azucena. A total of 175 molecular markers mapped on all 12 chromosomes of rice was used to detect QTLs underlying tolerance to Iow-K stress. These QTLs individually explained about 8 to 15% of the variations in relative changes of the parameters from K-sufficient to K-stress culture across the population. The differences in the changes of the parameters between Azucena and IR64 at the marker loci linked to the QTLs detected were from 16 to 39% above the overall means of the population. The identification of QTLs underlying the tolerance of low-K stress may be useful in selection for multiple traits which include Iow-K tolerance.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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