Resequencing Elucidates the Genetic Mechanism Underlying Elite Early-Maturing Potato Parent Kexin23

The maturity was earlier than that of the female parent Aula and comparable to that of the male parent Kexin4, indicating stable transmission of early-maturity genetic segments. Genetic structure analysis based on 465,000 SNP variants demonstrated that the parental contributions of Aula and Kexin4 to Kexin25 exceeded that to Kexin23, reflecting an asymmetric genetic contribution to Kexin23. A total of 5,147 Kexin23-specific variants were identified, which was significantly more than that in its sister line Kexin25 with 70 located in coding regions. Among these, the key gene C88_C12H1G014800 (encoding a zinc-finger protein) contained a premature termination mutation that suppressed expression, potentially associated with early maturity or high pollen viability. SNP analysis indicated that loci derived from Kexin23 in its offspring were enriched on chromosome Chr1-3 (with high Aula contribution) and chromosomes Chr2-1 and Chr4-2 (with high Kexin4 contribution). Contribution analysis revealed that Kexin23 transmitted an average of 55.75% of its genetic material to its offspring, with 44.02% derived from specific variants. These findings provide the first molecular-level insights into the formation mechanism of an elite potato parent, offering a theoretical basis for targeted improvement of early maturity and effective utilization of elite parents.