Pokkah boeng resistance in popular rabi sorghum cultivars and effects of the disease on leaf chlorophyll

Field experiments were conducted with nineteen sorghum (Sorghum bicolor L. Moench) cultivars that included fifteen rabi varieties, two kharif varieties and two rabi parental lines for evaluation of pokkah boeng (c.o. Fusarium subglutinans) resistance. Stem injection method of artificial inoculation was used to develop the disease under field conditions during two successive rabi seasons of 2015 and 2016. Leaf chlorophyll was measured by SPAD-502 chlorophyll meter to compare changes in chlorophyll content in inoculated plants over the control. Disease severity index ranged from 9.5–27.0% in 2015 and 10.4–32.5% in 2016. The cultivars widely varied in pokkah boeng resistance. CSV 19SS was identified as the most resistant among the test cultivars CSV 18R, DSV4, E 36-1 and CSV 8R as moderately resistant and SLR 30, RS 585 and M35-1 as susceptible cultivars. The disease had adverse effects on leaf chlorophyll content at vegetative stage particularly in susceptible cultivar (~ 21% reduction). This is the first information on the status of pokkah boeng resistance in popular rabi sorghum cultivars, which will help selection of varieties for cultivation.