where N1–N9 are the numbers of panicles with score 1–9:
1 = lesions on several pedicels or secondary branches;
3 = lesions on a few primary branches or the middle part of
panicle axis; 5 = lesions partially around the base (node) or
the uppermost internodes or the lower part of the panicle
axis near the base; 7 = lesion completely around the
panicle base or uppermost internodes or panicle axis near
the base with more than 30% of filled grains; 9 = lesion
completely around the panicle base or uppermost internodes
or the panicle axis near the base with less than 30%
of filled grains