New PCR-specific markers for pollen fertility restoration QRfp-4R in rye (Secale cereale L.) with Pampa sterilizing cytoplasm

Agnieszka Niedziela,Marzena Wojciechowska,Piotr Tomasz Bednarek

doi:10.1007/s13353-021-00646-z

Agnieszka Niedziela, Marzena Wojciechowska + Show 1 more

Open Access

https://doi.org/10.1007/s13353-021-00646-z

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Abstract

Pampa cytoplasmic male sterility phenomenon is used extensively in the rye hybrid breeding programs. It relies on sterilizing action of the cytoplasm resulting in non-viable pollen of female lines. The sterilizing effect is problematic for reversion, and efficient restores are needed. The most promising QTL is located on chromosome 4R, but other chromosomes may also code the trait. Advanced recombinant inbred lines formed bi-parental mapping population genotyped with DArTseq markers. Genetic mapping allowed the seven linkage groups to construct with numerous markers and represent all rye chromosomes. Single marker analysis and composite interval mapping were conducted to identify markers linked to the pollen fertility. Association mapping was used to detect additional markers associated with the trait. A highly significant QTL (QRfp-4R) that explained 42.3% of the phenotypic variation was mapped to the distal part of the long arm of the 4R chromosome. The markers localized in the QRfp-4R region achieve R2 association values up to 0.59. The homology of the 43 marker sequences to the loci responsible for fertility restoration in other species and transcription termination factor (mTERF) linked to Rf genes was established. Ten markers were successfully converted into PCR-specific conditions, and their segregation pattern was identical to that of unconverted DArTs.

Highlights

Cultivated rye (Secale cereale) is a cross-pollinated, diploid plant species known for its high tolerance to low winter temperatures and better withstanding adverse soil conditions than other cereals
Genetic mapping allowed the seven linkage groups to construct with numerous markers and represent all rye chromosomes
Chi-square adjustment tests revealed that the population deviated significantly from the expected 1:1 sterile-to-fertile segregation ratio (χ2 = 4090, p < 0.01 at α < 0.05) when contrasting sterile and fertile phenotypic classes were analyzed

Summary

Introduction

Cultivated rye (Secale cereale) is a cross-pollinated, diploid plant species known for its high tolerance to low winter temperatures and better withstanding adverse soil conditions than other cereals. The rye breeding programs focus on improving the high seed yield achieved via hybrid breeding based on heterosis. The exploitation of the heterosis effect results in a 20–25% higher grain yield than population breeding using the same agriculture Hybrids’ success depends on selecting inbred parental lines with the superior combining ability and exploiting the cytoplasmic male sterility (CMS) phenomenon. Cytoplasmic pollen sterility relies on the mitochondrial genome dysfunction that prevents the maturation of the male sex organs (stamens), resulting in defective pollen or its lack. The mating system in rye hybrid breeding requires three components, a maternal line carrying the CMS allele, a non-restorer germplasm for maintaining the CMS and a paternal line carrying restorer-of-fertility (Rf) nuclear genes which are able to reverse CMS effect

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