Journal of Taiwan Agricultural Research

Author:Pi-Jen Wu, Yu-Wen Lin, Charng-Pei Li, Chien-Hui Syu, Woei-Shyuan Jwo, Hsing-Mu Yen, Horng-Yuh Guo, Ming-Hsin Lai, and Dong-Hong Wu*

Abstract:

    The goal of this study was to improve the genetic uptake factor in indica rice cultivars through introgression of a japonica DNA segment that limits Cd accumulation. Our strategy was to screen the genetic potential of Cd uptake in Taiwan cultivars using a functional marker, to develop a novel indica line by marker-assisted selection, and then to evaluate the genetic improvement of the target breeding line under field conditions. Genotyping with the functional marker of OsNRAMP1 showed that the current Taiwan indica cultivars possessed a high accumulation allele that was consistent with the phenotype of the Cd accumulation trend between Taiwan indica and japonica cultivars. Subsequently, we selected advanced backcross inbred lines (BC₄F₂) from a chromosome 7 segment substitution line population that was derived from the cross between ‘Taichung Sen 10 (TCS10)’ and ‘Taikeng 2’ based on previous studies (2006–2011). An indica line, TCS10-qCdT7, that limits Cd accumulation was developed in the first cropping season of 2014 and possessed 96% genetic background similarity compared with the recurrent parent ‘TCS10’. In the first cropping season of 2015, this new breeding line exhibited the highly similar morphological characteristics compared with the indica variety ‘TCS10’, but had a Cd bio concentration factor in brown rice that was 44.4% less than that in the ‘TCS10’ parent. In summary, this study was conducted in a field environment and improved one of Taiwan’s popular indica cultivars using a marker-assisted backcross approach. The newly developed lines in this study would have the potential to contribute greatly to the future cultivation of rice production and increase the food safety within the Taiwan rice industry.

Key words:Cadmium accumulation, Field trial, Functional marker, Indica rice, Marker assisted backcross selection

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