Variability in Albugo candida and its reaction to local rapeseed and mustard in Manipur

Abstract

The present investigation was undertaken to study the variability of fi ve Albugo candida isolates collected from rapeseed and mustard growing areas (Iroisemba, Heirok, Kakwa, Lilong and Andro). The morphological features viz., shape, size and sporangial germination of different isolates was slightly different among the collected samples of the pathogen. Size of sporangia in different isolates ranged from 11.68 to 18.45 μm. Sporangial germination varied from 60 to 80 per cent. Pustule size, shape and disease index also varied among the isolates. Small size pustules were observed in Heirok isolate (1-2.5 mm), while large size was observed in Lilong isolate (1-5 mm). Pin head, raised, circular, surrounded by pure white pustules were observed in Heirok and Andro; pin head, raised, depressed at center pustules were observed in Iroisemba and Lilong, whereas pinhead, raised, circular, scattered pustules were observed for Kakwa isolates. Artifi cial inoculation at cotyledon stage on different local genotypes viz., CAULC-1, CAULC-2, CAULC3, CAULC-4, CAULC-5, CAULCR-1, CAULCR2, CAULCR-3, CAULCR-5, CAULCR-6 and CAULCR-7 showed variation in disease incidence and it ranged from 5.49-19.06 per cent.