Caracterização de genótipos brasileiros de trigo (Triticum aestivum L.) quanto a caracteres agronômicos e resistência tipo II à giberela

Abstract

Fusarium head blight (FHB), caused by fungi from the Fusarium spp. complex, is currently considered the most important disease for wheat crop in several parts of the world, due to the significant impact it causes to both yield and grain quality. Breeding has proven to be the most efficient approach to mitigate the problem. However, there are no cultivars available yet completely resistant to the pathogen, which justifies the search for sources of the trait, because genetic diversity is the raw material for plant breeding. The understanding regarding the association between the resistance and other traits is also useful to help planning selection strategies. In this context, the aim of this study was to characterize the variability present in two panels of Brazilian wheat cultivars for plant morphological and agronomic traits, and for type II resistance to FHB, and to characterize the disease damage in the quality of grains, as well as their association, in two wide panels of Brazilian wheat cultivars. The experiments were carried out at green house, during 2019 and 2020, and plant height, number of fertile tillers per plant, spike length, spike mass, number of spikelets per spike, number of grains per spike and grain mass per spike were assayed. Regarding plant disease and its impact on the spike and the quality of grains, Fusarium severity at the spike, number of grains per inoculated spike number of healthy grains per spike, number of wrinkled grains per spike, number of grains covered with a pink or white down per spike, grain mass per inoculated spike, healthy grains mass per spike, wrinkled grain mass per spike and grains covered with a pink or white down mass per spike were evaluated. Descriptive statistics, frequency distribution and Pearson correlation analyses were carried out. There is important genetic variability within the panels of Brazilian wheat cultivars for the agronomic traits assayed, as well for type II FHB resistance. There are promising genotypes to integrate breeding programs aiming the disease resistance. Several traits associate to each other, however few correlations, and with low magnitude, were found among agronomic and morphological traits with FHB resistance.