Fine mapping of a low tillering gene of rice


       Tillering in rice is one of the most important traits related to yield and useful for understanding the plant’s morphogenesis. In Japan, a low tillering variety, Aikawa 1, was developed and considered as a useful breeding material for yield improvement under certain conditions such as direct seeding cultivation. The low tillering characteristic in Aikawa 1 has been reported to be controlled by a single dominant gene, Ltn, on the long arm of chromosome 8. The objectives of this study were to develop a less tillering line with the genetic background of an elite tropical variety, IR64, by recurrent backcross breeding, and to find DNA markers tightly linked to Ltn for marker-assisted selection (MAS).
  As a result of linkage analysis using 94 plants of BC5F2 population (IR64/Aikawa 1//5*IR64), genetic distances between ssr5816-3 and A4765ssr5816-3 and the Ltn, and the Ltn and A4765 were ascertained as 6.9 cM, 1.7 cM, and 5.1 cM, respectively (Fig. 1). Based on the results of high-resolution mapping using 3,550 plants of BC5F3 population, the candidate region of the Ltn was specified between ssr6049-23 and ssr6049-2 and was located at 76.7 kbp on the Nipponbare genome sequence. (Fig. 1)
  This marker information is useful for conducting MAS for low tillering rice varieties. Low tillering lines with the genetic back ground of IR64 are useful breeding materials which are fully adapted to tropical conditions.

Figure, table


    Fig. 1. High resolution mapping of a low tillering gene, Ltn, on the long arm of rice chromosome 8.
    Fig. 1. High resolution mapping of a low tillering gene, Ltn, on the long arm of rice chromosome 8.
    The numbers inside the parentheses indicate the number of recombinant plants between the marker and Ltn.

Japan International Research Center for Agricultural Sciences Biological Resources Division


Technical A

Term of research


Responsible researcher

KOBAYASHI Nobuya ( Biological Resources Division )

FUJITA Daisuke ( International Rice Research Institute )

Ebron Leodegario A. ( International Rice Research Institute )

FUKUTA Yoshimichi ( Biological Resources Division )

Publication, etc.

Araki et al. (2003) Breeding research, 5 (Suppl 1), 95.

Fujita, D., Ebron, L.A., Araki, E., Fukuta, Y. and Kobayashi, N. (2007) Mapping of a gene for low tiller number, Ltn (t), in Japonica rice variety Aikawa 1. Proceedings of the 2nd International Conference on Rice for the Future, 448-452.

Japanese PDF

2008_seikajouhou_A4_ja_Part12.pdf456.47 KB

Related Research Highlights