Effect of stem gall disease on long-term germplasm preservation and quality seed production of coriander

Abstract

To know the health status of crops germplasm received from various sources, seed health testing (SHT) is a routine process for long-term conservation of healthy seeds in the National Genebank at ICAR-National Bureau of Plant Genetic Resources, New Delhi. In this process, 1328 accessions of coriander were received in the Plant Quarantine Division for SHT through Germplsm Conservation Division. In the present study, SHT revealed that most of the samples of coriander in which the seeds are deformed suffer from stem gall (seed gall) disease caused by Protomycesmacrosporus. Infection of P. macrosporus greatly affects the size and quality of seeds. As a result, infected seeds become excessively larger (from 6.46x5.01 to 12.76x3.94 mm) as compared to normal seeds and the germination capacity of the seeds is also lost. Deformity in size and measurement of infected seeds compared to healthy seeds indicates susceptibility to stem gall disease. Our observation revealed that the chlamydospores present in the infected seeds survive for a long period (~ 2 years) and if such infected seeds are conserved for long term in the National Genebank, it is possible that along with the seeds, dormant chlamydospores also survive. While on the one hand such diseased seed can prove to be the carrier in spreading the pathogen from one place to another, on the other hand, market demand will be affected which will result in lower prices for the farmers cultivating coriander.