Leaf and Dwarf Disease Incidence and Severity in Sweet Corn Hybrids, Along with Their Implications for Ear Yield
The production of sweet corn encounters considerable challenges stemming from biotic stressors, especially foliar diseases and viral infections, which diminish productivity even with expanded cultivation areas. This study was performed to evaluate the influence of prevalent leaf and dwarf mosaic virus diseases on the ear yield of 17 sweet corn hybrids. The study was conducted at the coastal area of Bengkulu University's experimental station (15 m asl). The experiment was set up on a randomized complete block design with three replications to allocate 15 experimental hybrids and 2 commercial varieties on the plots, each with a population density of 48 plants. Data were collected for leaf disease incidence, severity, and progress, dwarf disease symptoms, ear length and diameter, ear weight (unhusked and husked), kernel row number, kernel number per row, and ear yield. Leaf spots, eyespot with halos, corn leaf blight, and corn rust were the prominent leaf diseases found on the plant population as measured at three months after planting (MAP), with the level of incidence ranging from 23.29% to 32.17%, and the level of severity ranging from 15.17% to 21.67%. No significant differences were observed among the hybrids for the level of disease incidence and severity, and all hybrids exhibited moderate resistance to the leaf diseases under consideration. However, the evaluation of disease progress using the area under the disease progress curve (AUDPC) formula indicated that Caps3 × Caps17B was the most susceptible hybrid, while Caps2 × Caps22 was the most resistant hybrid. Dwarf disease, as indicated by variegata symptoms, was not found in all hybrids, notably in Caps3 × Caps17A, Caps15 × Caps22, Caps17A × Caps22, and Caps17B × Caps23. The remaining hybrids showed the symptoms, with incidence varying between 1.0% and 3.0% of the plant populations. The observations made on the characteristics of crop productivity showed that significant variations among the hybrids existed for ear yield and its contributing traits.