TITLE:
Decline in a Tilletia indica Teliospore Population in a Naturally Infested Arizona (USA) Wheat Field
AUTHORS:
Gary L. Peterson, Kathleen L. Kosta
KEYWORDS:
Karnal Bunt, Soil Survival, Teliospore Recovery
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.8 No.11,
October
12,
2017
ABSTRACT: Following a 2004-outbreak of Karnal bunt in an
Arizona wheat field where infection had not been detected in recent years, the
population and viability of Tilletia
indica teliospores in surface and subsurface layers of soil were monitored over
a four-year period. The field was seeded with two parallel 1.8 m × 190 m strips of wheat, 11 m apart and the remainder planted in non-host
barley. Thirty-eight 1.22 m2 wheat plots were harvested and seed
examined for infection. Several times throughout each season soil samples were
taken from each of 25 points throughout the field. Teliospores extracted from
subsamples of each soil sample were examined to estimate the number of
teliospores per gram soil and germination percentage. The average (SD) infection
observed for each of the four consecutive seasons was 7.05 (4.6), 2.89 (5.5), 0, and 0.004% (0). The average number of
teliospores recovered per gram of soil during the first sampling was 36 and 39 for
the 0.5 cm deep (surface) and 5.5 cm deep (subsurface), respectively, with an
average teliospore germination of 29%. By the last season, the average numbers of teliospores recovered were 5 and 2.5 per gram of
soil, respectively, with an average germination of 1.0%.