Scanning Electron Microscopy study of root tissue of muskmelon: Transferring Fusarium wilt resistance from snapmelon to muskmelon

The overall aim of this study was to investigate the level of Fusarium oxysporum f. sp. Melonis (F.o.m.) infection by studying the Scanning electron micrographs of transverse sections of parent inbred lines and developed F1 hybrid. The current study involved KP4HM-15 (Fusarium wilt resistant inbred line) in a crossing program with well adapted muskmelon cv. Punjab Sunehri (PS) to develop FW resistant hybrid possessing high yield and quality traits. Fom infects melon root and trails through the cortical and endodermal cells to reach xylem vessels by penetrating through pits. This is the first SEM appraisal of the whole tap root of field grown melon accessions, KP4HM-15, PS and PSxKP4HM-15 (MH-41) (F1 hybrid) aimed to discern the role of the root morphometric characters for imparting FW resistance. The trend for root epidermo-cortical thickness was KP4HM-15>PS>MH-41 while for the xylem diameter was MH-41> KP4HM-15>PS. The F1 hybrid exhibited FW resistance intermediate among the two parents i.e. absence or presence of less mycelia as compared to the susceptible parent (PS). However, the extent of infection was higher than the resistant parent KP4HM-15, which shows that partial resistance was transferred from KP4HM-15 to MH-41. This study accentuates the resistance gene mining and use of wild melon accessions to introgress FW resistance in commercial melon cultivars