Quantitative trait loci mapping for kernel row number using chromosome segment substitution lines in maize

Area of Science:

• Plant genetics
• Agricultural science
• Maize breeding

Background:

• Grain yield in maize is influenced by yield-related traits, such as kernel row number (KRN).
• Understanding the genetic basis of KRN is crucial for enhancing maize grain yield through genetic improvement.
• Kernel row number (KRN) is a key component directly impacting maize grain yield.

Purpose of the Study:

• To identify quantitative trait loci (QTL) associated with kernel row number (KRN) in maize.
• To evaluate the stability of KRN-associated QTL across different environmental conditions.
• To assess the potential of chromosome segment substitution lines (CSSLs) for improving maize breeding programs.

Main Methods:

• Construction of 130 chromosome segment substitution lines (CSSLs) using Nongxi531 (donor) and H21 (recipient) parents.
• Detection of quantitative trait loci (QTL) for KRN using stepwise regression and single-factor ANOVA across three environmental settings.
• Evaluation of phenotypic variation explained by individual QTL and identification of QTL expressed across multiple environments.

Main Results:

• Eleven quantitative trait loci (QTL) for kernel row number (KRN) were identified.
• Each QTL explained 9.87-19.44% of the phenotypic variation for KRN.
• Four QTL were consistently detected across more than two environments, indicating stable expression.
• The developed CSSLs possessed a higher number of favorable alleles for KRN compared to the recipient parent H21.

Conclusions:

• The identified QTL provide valuable genetic targets for marker-assisted selection to improve KRN in maize.
• The stable QTL are robust across different environments, facilitating their application in breeding programs.
• The CSSLs represent a valuable resource for developing improved H21 maize lines with enhanced KRN and grain yield.