Physiological aspects of winter wheat selection for adaptability

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Physiological aspects of winter wheat selection for adaptability

Khomenko L.

Institute of Plant Physiology and Genetics of NAS of Ukraine

31/17 Vasylkivska Str., Kyiv, 03022, Ukraine

Goal

Ta assess the varieties of winter wheat collection on the basis of drought resistance in the initial stages of seed germination in the solution of sucrose, which corresponds to a pressure of 16 atm, and during grain filling by the coefficient of realization of ear productivity potential. To determine the concentration of the cell juice on the flag leaf of plants in the earing phase, and to establish the resistance of different winter wheat varieties to drought. Methods. Laboratory, field, statistical. Results. Varieties of winter wheat grown in collection nurseries were divided into 2 groups according to the level of productivity and direction of use. These included 19 varieties of selection of the Institute of Plant Physiology and Genetics (IPPG) of the National Academy of Sciences of Ukraine (Kyiv selection), and 14 varieties of southern regions of Ukraine (Southern selection). During the evaluation of varieties of the collection of IPPG it was found out that in the early stages of seed germination in the solution of sucrose, which corresponds to a pressure of 16 atm, the level of drought resistance of varieties of Southern selection was 7.4% higher than Kyiv. Over the past 3 years, the average concentration of cell juice in varieties of Kyiv selection was 2% lower than in the South ones. The strong relationship (n ± P95=0.74 ± 0.12) was found between the level of drought resistance of collection varieties in the early stages of seed germination in the solution of sucrose 16 atm from the concentrations of cell juice of the flag leaf in the phase of earing wheat. With a record abnormal heat and drought in the period of grain filling in 2019, the varieties of Kyiv selection realized their genetically determined productivity potential by a factor of 4.0 better than the varieties of the Southern selection. Varieties with the high coefficient of realization of ear productivity potential were selected: Favorytka - 4.6; Bohdana - 5.4; Kalancha - 5.8, and Darunok Podillia - 6.1. Conclusions. It is proved that in the early stages of germination of wheat seeds in the solution of sucrose, which corresponds to a pressure of 16 atm, the level of drought resistance of varieties has the strong relationship (n ± P95=0.74 ± 0.12) with the concentration of cell juice of the flag leaf in the earing phase of wheat. It was found out that with the record abnormal heat and drought in the period of grain filling in 2019, winter wheat varieties of Kyiv selection 2.5% better realized their genetically determined ear productivity potential. Highly drought resistant and highly productive varieties of IPPG are distinguished: Favorytka, Bohdana, Kalancha, and Darunok Podillia. grain seed sucrose

Key words: Triticum aestivum L., varieties, drought resistance, concentration of cell juice, productivity, ear.

Improving productivity of the crops, among which winter wheat (Triticum aestivum L.) is the main food crop, remains a strategic objective of Ukraine's agricultural sector [1]. Contemporary climate change, which has a significant impact on agricultural production, is making adjustments to the objectives.

Extreme temperatures of changing climatic conditions are one of the most common abiotic adverse factors. Increasing the air temperature causes droughts, which increases the evaporation of water from the soil surface and induces additional stress factors that can greatly affect the required mineral nutrition requirements [2] and, in general, productive crop processes [3].

Thus, in Ukraine in recent years there is a steady tendency to decrease the annual rainfall [4] and the presence of droughts during grain filling.

Drought causes a number of physiological, biochemical and molecular changes at the cellular level [5] and suppresses plant photosynthesis [6]. Environmental stress (especially drought) leads to the accumulation of soluble carbohydrates and free amino acids as well as antioxidant compounds. These low molecular weight compounds are dissolved in water and are a part of the cellular juice of plants. They are non-toxic and protect cellular components from damage and degradation [7]. The cellular juice of plants contains spare proteins. The chemical composition and amount of cellular juice substances may vary and depend on the type of cells, tissues, plant genotype, their physiological state, and the effects of environmental factors [8].

Therefore, in the current climate change, the most actual problems of breeding and production of grain of the agricultural plants include finding out the mechanisms of plant resistance to adverse environmental conditions and creation of new varieties with high productivity, with increased levels of adaptability and grain quality.

Purpoe of research is to evaluate winter wheat varieties on the basis of drought resistance in the initial stages of seed germination and during grain filling by the factor of realization of the ear productivity. To determine the concentration of cellular juice of the flag leaf of the plants in the germination phase and to establish a connection with the dry resistance of winter wheat varieties.

Materials and methods. The research was conducted in the fields of the experimental farm of IPPG, NAS of Ukraine, Glevakha town, Vasylkiv district, Kyiv region. The material was mild winter wheat varieties grown in the comparative trial collection nursery during 2015-2019.

The establishment of the experiment with wheat varieties was carried out according to the method of examination of plant varieties of the group of cereals for suitability for distribution in Ukraine [9]. The meteorological and actual average weather conditions were used according to the weather archive from the website "Pogoda i klimat" (http://www.pogodaiklimat.ru).

The concentration of cellular juice of winter wheat varieties was determined in the hatching phase with a selection of 3 pieces of flag leaf from the main stem of plants on the device RL 3 (Made in Poland).

The level of drought resistance of cultivar samples at the initial stages of seed germination was determined on sucrose solution, which corresponds to the pressure of 16 atm, according to the method of Kozhushko MM [10]. The evaluation of the resistance of winter wheat varieties to drought was determined in the field by the coefficient of realization of the potential productivity of the ear (the difference of the ear weight measured with the ear weight in the flowering phase) [10].

The experiments were repeated 3-4 times. Statistical processing of the results was performed according to the method of Dospekhov BA [11] using AtteStat software (http://attestatsoft.narod.ru).

The climatic conditions of the Kyiv region in June 2015-2019 were characterized by an increased temperature regime with a small monthly rainfall of 57% of the norm during these years (Fig. 1).

Fig.1. The climatic conditions in June 2015-2019 during grain filling of winter wheat in the research area: а - the average air temperature, °С; b - the rainfall number per month, mm