Association of agronomical, morphological and anatomical traits with compensatory effect of stem reserve mobilization in common wheat genotypes under drought stress

Enhanced dry matter remobilization from vegetative tissues under terminal drought contributes to wheat grain yield. Two-year field study was conducted with aim to determine the range of compensatory effect (CE) based on stem dry matter remobilization in defoliated (10 days after anthesis) and intact plants of 61 wheat (Triticum aestivum L) genotypes included three groups: 17 standard genotypes, 27 F4: 5 families and 17 parent genotypes (only second season) used to make F4: 5 families. Agronomical, morphological and anatomical traits which influence the CE were analysed. Over two seasons CE was affected by environmental conditions. On average across standards and F4: 5 families CE was higher in the first season when mean stress intensity index of 0.145 (quantified as mild stress) was lower than 0.278 (quantified as moderate stress) obtained for the second season. Genotypes with higher number of spikelets and grains per spike, as well later flowering showed be yield loss compensation. Stem biomass and peduncle anatomical traits which determine potential for accumulation and remobilization of dry matter, such as stem wall thickness, photosynthetically not active parenchyma and number of large vascular bundles, showed positive correlation with CE. Although compensation of yield loss might be improved through breeding process (our F4: 5 families had slightly higher mean CE than their parents under moderate stress), it does not mitigate the effect of post-anthesis drought in great extent (up to 38.4%).