Identification of potato cyst nematode resistant genotypes using molecular markers

- We have evaluated potato breeding lines and varieties for PCN resistance genes.
- Nearly 60% of the breeding lines and varieties tested possessed H1 gene.
- No genotype was positive for the Gro1-4 and TG432 amplified in 24 genotypes.
- HC was amplified for 40 genotypes and 4 varieties and SPUD 1636 was amplified in 4 breeding lines and variety Kufri Swarna.
- The study will facilitate breeding of novel PCN resistant.

At present the resistant potato cultivars under cultivation do not possess enough resistance to wide range of potato cyst nematode (PCN) pathotypes (Ro1 to Ro5 of Globodera rostochiensis and Pa1 to Pa3 of Globodera pallida). Therefore, development of varieties having resistance against different PCN pathotypes is must however, large scale phenotypic evaluation for PCN is difficult and costly. Identification of resistance genes using DNA markers may be an alternative approach. In the present study, we have evaluated advanced generation breeding material along with five popular varieties grown in the Nilgiris (Kufri Jyoti, Kufri Giriraj, Kufri Girdhari, Kufri Swarna and Kufri Neelima) with known DNA markers for identification of PCN resistance genes (H1 gene against Ro1 and Ro4, Gro 1-4 and GroVI gene against Ro1, Grp1_QTL against Ro5, Pa2,3 and Gpa5 & Gpa6_QTL against Pa2,3). The results revealed that nearly 60% of the breeding lines and varieties tested possessed H1 gene whereas, no genotype was positive for the Gro1-4. The marker TG432 associated with QTL conferring resistance to G. pallida amplified in 24 genotypes. The SNP marker HC was amplified for 40 genotypes and four varieties. For G. pallida, marker SPUD 1636 associated with the QTL Gpa5 and Gpa6 was amplified in four breeding lines and variety Kufri Swarna. Hence, the result of the study will facilitate breeding of novel resistant varieties by efficient selection of ideal genotypes and pyramiding of resistant loci in a single genotype.