Multivariate approach for identifying wheat Triticum aestivum L. tolerant to heat and drought stress.

Breeding wheat for production in the Brazilian Cerrado region should aim at developing productive genotypes adapted to heat and drought conditions; therefore, this study evaluated the tolerance of wheat cultivars to heat/thermal and drought stress. To meet this objective, 30 wheat cultivars were cultivated in 3 greenhouse environments, namely control, drought, and heat, applying stress from the booting stage to the end of anthesis. The following parameters were evaluated: cycle, plant height, spike number per plant, spike length, spike weight, spikelet number per spike, percentage of fertile spikelets, number of grains per spike, and grain weight per spike. Principal component analysis and cluster analysis were performed by the Ward and “K-means” methods. Principal component analysis showed that the correlations between the productivity traits and the principal components were more affected by drought than by the control and heat environments. The cluster analyses formed five clusters for the control and heat environments and seven clusters for the drought environment. Grain productivity was highlighted in the heat environment for ‘BRS 210’, ‘BR18 Terena’, ‘IPR Catuara TM’, ‘CD 154’, ‘BR 220’, ‘MGS Aliança’, ‘IAC 350’, ‘IAC Tucunaré’, ‘BR 24’, ‘IAC 5 Maringá’, ‘UFVT1 Pioneiro’, and ‘CD 151 4’ with a positive relationship in principal component analysis. Considering spikelet number per spike in the drought environment, cultivars ‘BRS 208’, ‘IAC 350’, ‘Supera’, ‘BRS 210’, ‘IPR 85’, ‘IPR Catuara TM’, ‘Anahuac 73’, ‘BR 24’, ‘IAC 5 Maringá’, and ‘UFVT1 Pioneiro’ were highlighted. In the drought environment, most of the productivity-related traits exhibited components with negative relationships among cultivars and the evaluated traits, confirming their response to the induced stress.