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Table 2 Near Isogenic Lines (NILs) developed in IR64 genetic background with genes conferring novel and improved traits

From: IR64: a high-quality and high-yielding mega variety

Trait/QTL

Comments

References

Submergence tolerance (SUB1)

The SUB1 major gene was introduced by Marker Assisted Backcrossing (MABC) into IR64 and released in several countries.

(Septiningsih et al. 2009)

Drought tolerance (DRO1)

Breeding line developed by MABC showed improved drought tolerance through deeper root system.

(Uga et al. 2013)

Drought tolerance (qDTY2.2 + qDTY4.1)

Lines derived by MABC showed improved yield under severe drought stress.

(Swamy et al. 2013)

SPIKE gene (NARROW LEAF1)

NIL with this gene showed 15–36% higher yield when introgressed into IR64. The gene increases spikelet number.

(Fujita et al. 2013).

Improved agronomic traits

334 introgression lines developed in IR64 background using tropical japonica donors

(Farooq et al. 2010; Fujita et al. 2009; Kato et al. 2010; Tagle et al. 2016)

Anaerobic germination (AG1)

IR64-AG1 was developed by introgressing the AG1 QTL into IR64.

(Toledo et al. 2015)

Yield QTL identified from O. rufipogon

Some QTLs from low yielding wild rice O. rufipogon can increase yield in IR64 background.

(Cheema et al. 2008; Septiningsih et al. 2003)

Drought tolerance from O. glaberrima

A population of alien introgression lines using an accession of African rice O. glaberrima backcrossed to IR64 (BC2), and identified QTLs associated with drought-related traits.

(Bimpong et al. 2011)

Early-morning flowering (qEMF3)

NIL IR64 + qEMF3 with early morning flowering was developed using three backcrosses by marker assisted backcrossing and it flowered 1.5–2.0 h earlier in the day than IR64. In this case the donor was wild rice O. officinalis. This trait can confer tolerance to high temperature at anthesis.

(Hirabayashi et al. 2015)

Tolerance to P deficiency (Pup1)

Tolerance of P deficiency was introduced into IR64-Pup1, with the Pup1 gene for more efficient P uptake.

(Chin et al. 2011; Wissuwa et al. 2016)

Resistance to rice yellow mottle virus (RYMV)

Resistance to RYMV was introduced into IR64 background by marker assisted backcrossing.

(Ahmadi et al. 2001)