QTL analysis for grain protein content using SSR markers and validation studies using NILs in bread wheat

Area of Science:

• Plant genetics
• Agricultural science
• Quantitative trait loci (QTL) analysis

Background:

• Grain protein content (GPC) is a crucial quality trait in bread wheat.
• Understanding the genetic basis of GPC is essential for improving wheat varieties.
• Previous QTL mapping for GPC in bread wheat has been limited.

Purpose of the Study:

• To conduct the first QTL interval mapping for GPC in bread wheat.
• To identify and validate QTLs associated with GPC using recombinant inbred lines (RILs).
• To recommend significant QTLs for marker-assisted selection (MAS) in breeding programs.

Main Methods:

• Utilized a mapping population of 100 RILs grown across five environments in Northern India.
• Employed single-marker analysis (SMA), simple interval mapping (SIM), and composite interval mapping (CIM) for QTL detection.
• Validated identified QTLs using ten near-isogenic lines (NILs) derived from three crosses.

Main Results:

• Identified thirteen QTLs for GPC across individual environments, with seven detected using threshold LOD scores.
• Four QTLs (QGpc.ccsu-2B.1, QGpc.ccsu-2D.1, QGpc.ccsu-3D.1, QGpc.ccsu-7A.1) were consistently identified across multiple environments or methods.
• An additional QTL (QGpc.ccsu-3D.2) identified using all environmental means was also deemed important.
• Validation in NILs confirmed associations between markers and seven identified QTLs.

Conclusions:

• Five significant QTLs for GPC have been identified and recommended for marker-assisted selection (MAS).
• The study provides valuable genetic resources for improving GPC in bread wheat.
• Further identification of markers linked to QTLs will enhance MAS efficiency for GPC enhancement.