Rl. Villareal et al., RESISTANCE TO KARNAL BUNT (TILLETIA-INDICA MITRA) IN SYNTHETIC HEXAPLOID WHEATS DERIVED FROM TRITICUM-TURGIDUM X T-TAUSCHII, Plant breeding, 112(1), 1994, pp. 63-69
Synthetic hexaploids (SH) developed at the International Maize and Whe
at Improvement Center (CIMMYT), involving four Triticum turgidum and n
ine T. tauschii parents, were evaluated for resistance to Karnal bunt
(KB) (Tilletia indica Mitra) during three crop seasons over three year
s at Ciudad Obregon, Sonora, Mexico. Ten tillers of each SH at boot st
age, taken at random, were injected with a suspension of sporidia in w
ater (10,000 spores/ml of water). At maturity the inoculated spikes we
re threshed individually and evaluated for the percentage KB-infected
grains. Based on the mean KB score of each entry for three seasons, 49
% of the SH were immune (0 % infection) to KB. Highly resistant expre
ssions characterized the SH which appeared to be influenced by the res
istance of their T. turgidum and/or T. tauschii parents. The overall m
ean infection of the SH wheats was 0.24 % compared to 56.14 % in the s
usceptible bread wheat check cultivat 'WL711'. Transfer of K.B resista
nce genes from SH wheats into bread wheat is currently underway at CIM
MYT.