TY  - PRO
AU  - Xiuling Zhang
AU  - Duveiller,E.|Dubin,H.J.|Reeves,J.|McNab,A.
AU  - Haley,S.D.
AU  - Jin,Y.
ED  - Centro Internacional de Mejoramiento de Maiz y Trigo (CIMMYT), Mexico DF (Mexico)
TI  - Repeatability of tan spot resistance evaluation in wheat
SN  - 970-648-001-3
U1  - 633.1194 
PY  - 1998///
CY  - Mexico, DF (Mexico)
PB  - CIMMYT|UCL|BADC
KW  - Disease resistance
KW  - AGROVOC
KW  - Inoculation methods
KW  - Plant diseases
KW  - Plant production
KW  - Spots
KW  - Triticum
KW  - CIMMYT
N2  - Tan spot is an increasingly important problem for winter wheat production in the northern Great Plains of the USA. Reduced-tillage (or no- tillage) planting into spring wheat stubble, widely credited with contributing to increased winter survival, is largely responsible for the disease increase. The objective of our study was to assess the inherent repeatability of our greenhouse seedling screening procedures as a complement to field screening for improvement of tan spot resistance. Thirty-seven wheat genotypes (released cultivars and experimental lines, both spring and winter growth habit), representing a range of resistance reactions, were tested with a tan spot isolate at four different time periods ("sets"). For each set, materials were planted in a randomized completed block design with two replications. Set inoculations, repeated at three-day intervals, were performed at the two-leaf stage (when the second leaf was fully expanded) with a conidial suspension of about 7,000 spores ml-1. The repeatability of tan spot resistance evaluation obtained by the partitioning of variance components was very high (90.5%), suggesting a high degree of consistency between different evaluation periods. It was concluded that our current greenhouse screening procedure is very reliable and consistently identifies germplasm with a high degree of resistance at the seedling stage. More research is needed, however, to verify the association between tan spot resistance reactions in juvenile and adult plants
ER  -