The influence of meteorological conditions of vegetation on the content of photosynthetic pigments in leaves of soft spring wheat

Under the conditions of the Kirov region the state of the pigment complex of leaves of soft spring wheat of 2 varieties and 9 promising lines was studied during “tillering - flowering” period to determine the influence of weather conditions in years contrasting in moisture availability and temperature indicators. During the study period of 2016-2017, the content of chlorophylls (Chl a, Chl b) and carotenoids (Car) in the majority of genotypes in one and the same phases of plant development statistically significantly varied (at p ≤ 0.05). The C-65, C-122 and C-129 lines were selected, the leaves of which contained more than the average of the experiment or an equal amount of pigments. It is shown that vegetation conditions had a greater impact on the quantitative content of pigments, and to a lesser extent on their ratio. An insignificant and medium (7.1 - 14.5%) inter-varietal variability in the content of Chl a in the reaction centers (RC) of photosystems, Chl b and Car in the leaves was noted. The average variability noted in the flowering phase allows to use the absolute values of the pigment content as an additional component in the selection of breeding lines. Under conditions of excessive moisture, paired correlations (at p ≤ 0.05) were found between plant height and Chl a and Chl b content in the tillering phase (r = -0.67 and -0.69, respectively), and also with Car content in the flowering phase (r = -0,65). The number of Chl a, Chl b and Car in the phase of entering the tube was statistically significantly correlated with productive bushiness (r = 0.67, 0.64 and 0.68, respectively), the number of grains of the main spike (r = 0.70, 0.63 and 0.68) and the mass of grain per plant (r = 0.69, 0.61 and 0.73). Under drought conditions, the content of Chl a and Chl b was significantly correlated with the length of the main spike (r = 0.71 and 0.65, respectively) and the mass of the main spike grain (r = 0.73 and 0.77). An assessment of genotype-environment interactions between the same parameters characterizing the pigment complex in different years showed that the growing season conditions strongly influenced the severity of most of them. Weak interaction genotype - year was manifested by the Car content in 1 g of dry matter in the flowering phase (rg = 0.61).