Evaluation of Yield, Reaction to Diseases, and Grain Physical Attributes of Some Introduced Rice Hybrids in Ghana

Table 2

Descriptive key for recording leaf blast disease severity.

Score	Description of symptoms
0	No lesions observed
1	Small brown specks of pinhead size or long brown specks without sporulating centre
2	Small roundish to slightly elongated, necrotic grey spots, about 1-2 mm in diameter with a distinct brown margin
3	Lesion type is the same as in scale 2, but a significant number of lesions are on the upper leaves
4	Typical susceptible blast lesions, 3 mm or longer, infecting less than 4% of the leaf area
5	Typical blast lesions infecting 4–10% of the leaf area
6	Typical blast lesions infecting 11–25% of the leaf area
7	Typical blast lesions infecting 26–50% of the leaf area
8	Typical blast lesions infecting 51–75% of the leaf area and many leaves are dead
9	More than 75% leaf area affected