Canonical Correlation Analysis and Grouping of Bread Wheat Genotypes Based on Morphophenological Traits and Fusarium Head Blight Tolerance Indexes

Fusarium head blight disease is one of the most important and destructive diseases of wheat in hot and humid climates, which, in addition to reducing yield, causes the accumulation of mycotoxins in the grain, which is dangerous for humans and animals. Passive resistance against Fusarium includes many morphological and phenological traits such as plant height, flowering time, heading time, number of spikes and spike density, which help to escape the disease or create a kind of resistance to Fusarium head rot disease. The purpose of this study was to compare the studied genotypes with respect to Fusarium head blight disease and to estimate the simple and canonical correlation between morphological traits and disease resistance traits.

In order to evaluate 92 improved and native genotypes of Iranian bread wheat against Fusarium head blight in two crop years (2019-2022), experiments were conducted in the form of a randomized complete block design in the farm of Gorgan University of Agricultural Sciences and Natural Resources. Morphological traits measured included plant height (PH), spike length (SL), and number of seeds per spike (TSS), and agronomic traits measured included heading time (DTH) and flowering time (DTF). Disease traits were: disease incidence (INC), disease severity (SEV), Fusarium damaged kernels (FDK), FHBdx index and ISK.

For all disease-related traits and morphophenological traits, a significant difference (p<0.001) was observed between genotypes. According to the result of correlation analysis, there was a positive and significant correlation (p<0.001) between DTH, DTF and PH traits with traits related to Fusarium head blight of wheat. The analysis of canonical correlation between the variables of disease-related traits and morphophenological traits showed a significant canonical correlation (0.687), which explains 81% of the total variance. According to the results of cluster analysis based on morphophenological traits and traits related to FHB disease, the investigated genotypes were classified into five separate group, the genotypes of the first group had a lower average among the other groups and the average of all genotypes in terms of all traits related to FHB disease and at the same time, compared to other groups, they were earlier.

Rizhav, Chamran, Darya, Arta, Neishabur and Gonbad cultivars showed the highest resistance to Fusarium disease in the study and can still be used as parental cultivars to improve new wheat cultivars resistant to Fusarium Head Blight disease. Also, among the landrace, three genotypes, Larg Karaj, Parand Saveh, and Malayer, showed acceptable resistance, which indicates that some landrace cultivars are also relatively resistant to Fusarium head blight disease, and it may be possible if they have complementary gene loci of specific genes. Resistance to this disease can probably be used for breeding purposes and programs for resistance to Fusarium disease, which needs further investigation in future studies.