QTLs associated with root traits increase yield in upland rice when transferred through marker-assisted selection

Area of Science:

• Agricultural Science
• Plant Breeding
• Genetics

Background:

• Upland rice cultivation faces challenges in drought-prone environments, limiting yields.
• Root system architecture is a critical factor for improving rice resilience and productivity in water-scarce conditions.

Purpose of the Study:

• To enhance upland rice yields by improving root morphology through quantitative trait loci (QTL) introgression.
• To evaluate the effectiveness of marker-assisted backcross breeding (MABC) for transferring beneficial root traits into an elite upland rice cultivar.

Main Methods:

• Marker-assisted backcross breeding (MABC) was employed to introgress four root trait QTLs into a recurrent upland rice parent.
• Introgressed lines and the recurrent parent were field-tested for six years by farmers in Eastern India.
• Controlled experiments assessed root morphology differences between introgressed lines and the recurrent parent.

Main Results:

• The introgressed QTLs significantly increased rice yield by 1 t ha(-1) under favorable upland conditions.
• Lines with introgressed QTLs exhibited significantly longer roots (14 cm longer at 2 weeks after sowing) compared to the recurrent parent.
• QTL effects on yield were less detectable in highly variable, low-yielding environments due to soil-water heterogeneity.

Conclusions:

• Marker-assisted backcross breeding (MABC) is an effective strategy for improving farmer yields of upland rice by introgressing multiple root QTLs.
• The introgression of root trait QTLs directly contributes to both improved root systems and increased crop yields.
• This research led to the development and release of a novel upland rice cultivar, Birsa Vikas Dhan 111, in India.