Evaluation of Field Screening Techniques for Resistance to Sorghum Grain Molds. R. Bandyopadhyay, Plant Pathologist, Cereals Program, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru P.O., Andhra Pradesh 502 324, India. L. K. Mughogho, Principal Plant Pathologist, Cereals Program, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru P.O., Andhra Pradesh 502 324, India. Plant Dis. 72:500-503. Accepted for publication 8 December 1987. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/PD-72-0500.

Three methods of promoting grain mold development (overhead sprinkler irrigation on rain-free days, inoculation of panicles with mold-causing fungi, and bagging of panicles) for field screening of sorghum lines for resistance to grain molds were evaluated for two seasons (1982 and 1983) using genotypes susceptible and resistant to grain mold. Threshed grain mold ratings (TGMRs) of these genotypes in overhead sprinkled plots were not significantly different from ratings in unsprinkled plots when rainfall was abundant and frequent from flowering through grain maturity to harvest. In a season of low and infrequent rainfall, however, TGMRs were higher in sprinkled plots. Grain germination was significantly lower in sprinkled than in unsprinkled plots in the season of frequent rainfall. There were no significant differences in TGMRs between inoculated and/or bagged treatments and noninoculated and nonbagged treatment for susceptible genotypes in years of either frequent or infrequent rainfall. Inoculation and bagging increased moldiness in resistant genotypes but not to the threshold level of susceptibility. Screening nursery results (1983–1985) showed that mold resistance screening without inoculation and bagging of panicles appears feasible if overhead sprinkler irrigation is used from flowering to harvest.