Novel sources of resistance against foliar diseases identified among the newly derived tropical inbreds of field corn

Abstract

The investigation was carried out at ICARIARI, Regional Research Centre, Dharwad, with the objectives to screen newly developed inbred lines against turcicum leaf blight (TLB), curvularia leaf spot (CLS) and maydis leaf blight (MLB) and common rust (CR) to identify new sources of resistance during Kharif 2020 and 2021. The grain yield, and flowering traits were recorded on 45 newly developed inbred lines. The results revealed that none of the inbred is immune to any of the four foliar diseases. However, highly resistant lines are identified against TLB (5 lines viz., PDM 4641, PDIM 638, PDIM 639, PDIM 697, PDIM 635), CLS (5 lines viz., PDIM 697, LM-14, C-79, CDM-1105, TC-6), MLB (6 lines viz., C-79, CDM-1105, PDM-10, C-83, PDM-134, C-2765) and CR (7 lines viz., C-79, CM 202, PDIM 635, PDIM 805, PDIM 697, PML-50, C-67). Among these, PDIM 635 and PDIM 697 displayed resistance against all the four diseases studied, while PDIM 638 and PDIM 639 exhibited resistance against TLB, CLS, and MLB, and C 79 and C 67 showed resistance against CLS, MLB, and CR. Further, there are a few more inbreds that displayed resistance against two of the four diseases studied. The distribution of inbred lines with respect to disease scores showed similar trends for foliar diseases implying the possible linkage of resistance genes against different foliar diseases or multiple disease resistance. Further, the analyses of genetic parameters revealed high PCV, GCV, heritability, and GAM of the traits studied. Based on the results it was suggested to select inbreds for hybrid breeding in the short run and to improve foliar disease resistance through population improvement approaches such as recurrent selection methods.