Knowledge Center Catalog

Diallel analysis of Septoria tritici blotch resistance in winter wheat

By: Contributor(s): Material type: TextTextPublication details: Mexico, DF (Mexico) CIMMYT : 1999ISBN:
  • 970-648-035-8
Subject(s): DDC classification:
  • 632.4 GIN
Summary: In the winter wheat area of the northern Great Plains, leaf spot complex has been problematic in the past decade. In years with high precipitation from late April to July, septoria tritici blotch (STB), caused by Septoria tritici, is most prevalent. As part of our effort to improve STB resistance, inheritance of STB resistance was investigated by an eight-parent full diallel scheme. Parents, F 1 , and reciprocal F 1 were planted on three different dates. Within each planting date, three to five seeds of each experimental unit were planted in the greenhouse. Materials were arranged in a randomized complete block design (RCBD) with three replicates. Plants at the second-leaf stage were inoculated with a bulk of six S. tritici isolates. Significant general combining ability (GCA), specific combining ability (SCA), and reciprocal effects were observed in the analysis of variance. The ratio of GCA sum of squares relative to SCA sum of squares suggested that GCA was more important than SCA. Additive effects played the major role in host response to STB, while non-additive effects were also detected. General combining ability effects of individual genotypes were in close agreement with parental performance. KS94U338, a genotype with resistance derived from Triticum tauschii, had the lowest STB score and the highest general combining ability. This result indicates that this genotype, possessing resistance distinct from other known sources, should prove useful in breeding efforts to improve STB resistance in wheat.
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In the winter wheat area of the northern Great Plains, leaf spot complex has been problematic in the past decade. In years with high precipitation from late April to July, septoria tritici blotch (STB), caused by Septoria tritici, is most prevalent. As part of our effort to improve STB resistance, inheritance of STB resistance was investigated by an eight-parent full diallel scheme. Parents, F 1 , and reciprocal F 1 were planted on three different dates. Within each planting date, three to five seeds of each experimental unit were planted in the greenhouse. Materials were arranged in a randomized complete block design (RCBD) with three replicates. Plants at the second-leaf stage were inoculated with a bulk of six S. tritici isolates. Significant general combining ability (GCA), specific combining ability (SCA), and reciprocal effects were observed in the analysis of variance. The ratio of GCA sum of squares relative to SCA sum of squares suggested that GCA was more important than SCA. Additive effects played the major role in host response to STB, while non-additive effects were also detected. General combining ability effects of individual genotypes were in close agreement with parental performance. KS94U338, a genotype with resistance derived from Triticum tauschii, had the lowest STB score and the highest general combining ability. This result indicates that this genotype, possessing resistance distinct from other known sources, should prove useful in breeding efforts to improve STB resistance in wheat.

Global Maize Program

English

9910|AGRIS 0001

INT3400

CIMMYT Publications Collection


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