Bacterial streak of wheat is best controlled by resistant cultivars, but there are difficulties associated with screening for resistance under field conditions. Screening for resistance under controlled conditions could facilitate the development of resistant cultivars if there is a good relationship between disease reaction and disease severity. The objective of this study was to determine the relationships between bacterial streak reactions on primary leaves of seedlings or flag leaves of adult plants and bacterial streak severity on adult plants in the field. Fifty spring wheats and 24 winter wheats were evaluated. Except for spring wheat cultivar reactions on primary leaves, reactions (ranks) of greenhouse-grown cultivars were significantly and positively related (r ranged from 0.60 to 0.64 with P less than or equal to 0.0012) to ranks of cultivars evaluated for bacterial streak severity. However, selection for low percentages of water-soaking under controlled conditions would keep a few wheats that were susceptible in the field and discard several wheats that were resistant in the field. Because of these discrepancies we cannot recommend inoculation under controlled conditions as a reliable means of screening a random sample of wheats for bacterial streak resistance.
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E. A. Milus (1996) studied this question.