Are Nonwoven Synthetic Pollination Bags a Better Choice for Sorghum Breeding?

This work investigated the effects of seven pollination bag treatments on three varieties of sorghum
for: grain loss to birds; total weight of five panicles (g); total grain weight of five panicles (g); average
grain weight per panicle (g); germination per cent; and occurrence of grain mold during 2016.
Varieties were: 1167048 hybrid (brown seeded); BR007B (red seeded); and P9401 (white seeded).
The bag treatments were: 1. No bagging; 2. Kraft paper; 3. Kraft paper + plastic bag screen; 4 Used
duraweb® SG1; 5. Used duraweb® SG2; 6. New duraweb® SG1; 7. New duraweld® SG2. High bird
pressure resulted in 100% seed loss on uncovered panicles and 75% under Kraft paper pollination
bags. Birds preferred white seeded P9401, which led to no seed recovery under Kraft paper bags.
There was virtually no bird damage with all other pollination bags. For panicle and grain yields the
varieties performed in the order 1167048>BR007B>P9401. Unprotected panicles and paper bag
treatments had the lowest yields. Panicles covered with the new synthetic bags exhibited 195 to
652% higher yields compared to Kraft paper bags. Varieties x bag type interactions were not
important as they contributed 4 to 6% to the total sum of squares for yield traits. Germination test
under normal and stress conditions showed no significant adverse effect of bag treatments on seed
health. Reused bags performed as well as new bags for all of these traits. Varieties differed
significantly for the occurrence of five grain mold pathogens, with highest occurrence of Alternaria, up
to 40%, on 1167048 hybrid. Of the five pathogens, bag types differed significantly for Phoma with the
highest occurrence of 9% on re-used duraweb®SG2 bags. Thus bags require disinfecting and
cleaning before re-use. It is concluded that nonwoven synthetic bags are a better choice than the
Kraft paper pollination bags for increasing the grain yield and virtually eliminating the bird damage in
sorghum.