Mapping QTL for popping expansion volume in popcorn with simple sequence repeat markers

Area of Science:

• Plant genetics
• Quantitative genetics
• Crop breeding

Background:

• Popping expansion volume is a critical quality trait in popcorn (Zea mays L.).
• The genetic basis of popping expansion volume is not well understood.
• Popcorn x dent corn crosses present unique genetic complexities, such as the gametophyte factor Ga1(s).

Purpose of the Study:

• To map quantitative trait loci (QTLs) associated with popping expansion volume in a popcorn x dent corn cross.
• To compare the efficiency of phenotypic selection, marker-based selection, and marker-assisted selection for improving popping expansion volume.

Main Methods:

• Screened 259 simple sequence repeat (SSR) primer pairs for polymorphism between dent corn (H123) and popcorn (AG19) inbreds.
• Developed 160 S(1) families from a backcrossed population for analysis.
• Utilized popping tests to gather data on popping expansion volume and employed QTL mapping techniques.

Main Results:

• Identified four QTLs on chromosomes 1S, 3S, 5S, and 5L that collectively explain 45% of the phenotypic variation for popping expansion volume.
• Heritability (h²) for popping expansion volume was high at 0.73 on an S(1) family mean basis.
• Marker-assisted selection was predicted to be 106% as efficient as phenotypic selection, while marker-based selection was 92% as efficient.

Conclusions:

• Phenotypic selection is predicted to remain the most effective method for selection in popcorn x dent corn crosses.
• Despite advancements, the high heritability of popping expansion volume supports continued reliance on traditional selection methods.
• The identified QTLs provide valuable targets for future genetic studies and breeding efforts in popcorn improvement.