EVALUATION OF POTATO GERMPLASM FORLATE BLIGHT AND POTATO CYST NEMATODERESISTANCE UNDER NORTH-WESTERNINDIAN HILLS

Abstract

Late blight disease caused by the fungus Phytophthora infestans is the main yield limiting factor amongst
the diseases of potato in India and across the globe. Potato Cyst Nematode/PCN (Globodera spp.) is another biotic factor
of economic importance and is a quarantine organism. Exploitation of genetic resistance is the most preferred management
strategy. In the present study, indigenous potato genotypes collected from different parts of the country along with checks
were evaluated for their resistance against late blight under natural epiphytotic field conditions and in laboratory under
artificially inoculated conditions including detached leaf and tuber slice assays and PCN through Root ball technique
during 2020-2023. The converted field scale values i.e. average AUDPC value ranged from 7 in highly resistant genotype
Rangpuria to 1596 in susceptible accession AGR/56. The field blight response was comparatively more correlated (r =0.63)
with susceptibility levels measured in the detached leaf assay compared to that with tuber slice assay (r =0.48). Genotypes
Kanpuria Safed, JG-1, Rangpuria and Desi Aloo showed resistance to late blight both under laboratory and field conditions.
For PCN, Garlentic, Jeevan Jyoti and JG-1 have combined resistance (0 female/root ball) over the years to both the species.
Majority of the studied genotypes have medium to high pollen viability with desirable tuber traits and yield advantage.
The identified resistant genotypes excel their usage as parental lines in breeding for biotic stress resistance specifically
for late blight and PCN.