Near-isogenic lines for days to heading with an Indica-type variety IR64 genetic background


IR64, recognized globally as a high quality rice variety, was first released by the International Rice Research Institute (IRRI) in 1985. To increase yield potential and broaden the adaptability of IR64, a set of near-isogenic lines (NILs) of IR64 with various days to heading (DTH) were developed using Japonica-type high-yielding varieties including new plant type varieties as donor parents.
A total of five NILs were developed through marker-assisted selection. Three NILs having quantitative trait loci (QTLs) from IR65600-87-2-2-3 (IR64-NIL7) and Hoshiaoba (IR64-NIL10 and IR64-NIL11) showed earlier heading by 5 days than IR64, while two NILs from IR65598-112-2 (IR64-NIL8) and IR69125-25-3-1-1 (IR64-NIL9) showed later heading by 10 days (Table 1). Three QTLs for short DTH were detected on chromosomes 8, 6 and 11, while two QTLs for long DTH were detected on chromosomes 6 and 11 (Fig. 1 and Table 1).
These lines are the first set of NILs carrying various QTLs for DTH suitable for tropical conditions. These NILs can be used to understand the genetic basis of DTH and the effects of a single QTL/gene by testing it under different environmental conditions. Furthermore, early heading NILs could be useful for avoiding abiotic stresses at the late growth stage, while late heading NILs could be useful as breeding materials to develop high yielding lines.

Figure, table

  1. Fig.1. Graphical genotype of IR64-NIL's chromosomes which contain QTL regions for DTH(indicated by red circles) derived from donor parents
  2. Table1.Agronomic characteristics of near-isogenic lines of IR64 for days to heading

Japan International Research Center for Agricultural Sciences Biological Resources and Post-harvest Division


Administration A

Research project

Development of agricultural technologies in developing countries to respond to climate change

Program name

Environment and Natural Resource Management

Term of research

FY 2011 (FY 2005-FY 2011)

Responsible researcher

Kobayashi Nobuya ( 農研機構 次世代作物開発研究センター )

Fujita Daisuke ( 農研機構 作物研究所 )

Ishimaru Tsutomu ( 生物資源・利用領域 )

Fukuta Yoshimichi ( 熱帯・島嶼研究拠点 )

Publication, etc.

Fujita et al. (2011) Plant Breeding, 130:526-532.

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English PDF

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