This result was obtained from an F2 population segregating for Tomato yellow leaf curl disease (TYLCD). The population was genotyped with a SNP marker linked to the resistant loci.
A population of 82 F2 lines were genotyped with Ty-3 SNP marker and the ratio 1:2:2 turned up. What does it mean??
Did you check the phenotype of those 85 lines? If they co-segregate with the trait, genotypic ratio you observed might be the reason of selection bias from the pool. In that case, as @Asif suggested, you should increase the sample size.
Probably it is because of sampling error due to inadequate population size.
Michael Teye Barnor Sampling error is the most probable explanation. But, if your segregation ratio 1:2:2 will be repeatably obtained in independent F2 populations, it will mean that one SSR allele is linked to reduced viability of gametes (survival rate =0.5). By the way, you have not said which type of allele had a minor proportion - Resistant or Susceptible-linked.
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