A Single Dominant Gene for Rust Resistance in Pearl Millet

Abstract

Pearl millet rust (Puccinia penniseti Zimm = P. substriata var. indica) can reduce yields in hybrid seed production fields, quality in forage, and occasionally grain yields. Results are reported on the inheritance of a source of rust resistance discovered in crosses which involved one Sf progeny, #2696-1-4, selected from a pearl millet (Pennisetum americanum (L.) Leeke) germplasm accession originating from Chad. F1, F2, BC1, BC2 plants and the parents of crosses between the resistant source and two different susceptible male sterile lines were evaluated under severe rust pressure at three locations in India. Progeny of 2696-1-4 and the F1 hybrids between 2696-1-4 and male sterile lines were all resistant, while the male sterile lines were severely rusted at each location. In general, F2 populations from susceptible ✕ resistant crosses showed a good fit to a 3 resistant: 1 susceptible ratio and the backcrosses involving susceptible male-sterile lines as recurrent parents showed a reasonably good fit to 1 resistant:! susceptible, indicating that rust resistance is conferred by a single dominant gene and susceptibility by its recessive allele. We propose the symbols Rpp1 and rpp1 for these genes