QTL Mapping of Tiller Number in Korean Japonica Rice Varieties

Area of Science:

• Plant genetics and breeding
• Agricultural science
• Molecular biology

Background:

• Tiller number is a crucial trait influencing rice yield.
• Understanding genetic control of tiller number is key for crop improvement.
• Korean japonica rice varieties are important for global agriculture.

Purpose of the Study:

• To identify quantitative trait loci (QTLs) controlling tiller number in Korean japonica rice.
• To analyze the genetic basis of tiller number variation in a recombinant inbred line population.
• To evaluate the stability and pleiotropic effects of identified QTLs.

Main Methods:

• Construction of a genetic map using KASP and CAPS markers.
• Analysis of 160 recombinant inbred lines (RILs) under greenhouse conditions.
• QTL mapping and validation in a backcross population under field conditions.
• Genotyping for a functional variant in the 5' UTR of OsTB1.

Main Results:

• A major QTL, qTN3, for tiller number was identified on chromosome 3.
• qTN3 demonstrated stability across different generations and environments.
• qTN3 showed co-location with QTLs for panicle number and culm diameter, suggesting pleiotropy.
• A 4 bp TGTG insertion/deletion in the 5' UTR of OsTB1 was associated with reduced tiller number.

Conclusions:

• The identified QTL, qTN3, provides a valuable genetic resource for improving tiller number in japonica rice.
• A high-resolution melting marker was developed for efficient marker-assisted selection.
• qTN3 can be utilized in breeding programs to develop high-yielding japonica rice varieties with optimal tiller numbers.