Screening and identification of new foliar blast resistant sources in pearl millet (Pennisetum glaucum L. R. Br.)
National Academy of Agricultural Sciences, New Delhi, (2019)Abstract
Foliar blast, aka leaf spot, caused by Magnaporthe grisea, is an emerging threat to pearl millet growing areas affecting both forage and grain production of pearl millet hybrids, varieties and parental lines. Towards identification of new diverse sources of blast resistance, pearl millet germplasm collection comprising of 300 accessions originating from 25 countries were evaluated against the Delhi isolate of pathogen (PMg_Dl) under natural epiphytotic conditions. Blast severity was recorded at 30 and 60 DAS using a 0–9 progressive scale. Based on disease rating, the plants having score of ≤3 were rated as resistant and those with score of ≥4 as susceptible. In field screening during 2017 and 2018, 206 accessions were found foliar blast resistant and out of these, 34 accessions were completely free from blast symptoms. The resistant accessions showed varied disease responses when infected with single isolates, suggesting the presence of diverse resistance genes/alleles in these accessions. The accessions, IP 11423, IP 11353, IP 3122, IP 7910 and IP 7941 showed HR towards infection (score ≤1) whereas IP 4020, ICML 22, ICMB 89111-P2, ICMB 843 and LGD 1-B-10 were found highly susceptible (score ≥8). Highly resistant and susceptible accessions were chosen for the development of biparental mapping population for identification of new foliar blast resistance gene(s). Collection of accessions with broad genetic spectrum and isolate specific blast resistance will provide an opportunity for isolation of unknown blast resistance genes and/or their allelic variants that can be deployed in future pearl millet breeding programs.