Agrobiological selection of spring barley varieties by adaptive features

Abstract

Scientifically grounded selection of varieties in specific growing conditions allows significant reducing the risks of shortfall in yields. Therefore, the agrobiological selection of spring barley varieties by adaptive characteristics determined the relevance of the study.

The study purpose was to define the criteria for selection of breeding material that is promising in terms of adaptive and yielding parameters upon creating drought-resistant spring barley varieties.

Material and methods. The study was carried out using B.A. Dospekhov's field experimentation methods and the method of the state variety trials of agricultural crops.

Results and discussion. It was established that in the agroclimatic conditions of the east-northern steppe of Ukraine the use of universal barley varieties allows solving the problem of stabilizing the yield of this crop.

Determination of the cenotic structure of crops according to the plant performance objectively characterizes varieties in terms of agroecological fitness and adaptive potential by maintenance of the ontogenetic homeostasis of plants in arid conditions of cultivation. If the stress factor of "reservoirs of productive moisture in soil" affects, the objectivity of selection of drought-resistant varieties only by direct traits of the spike performance (length, weight, grain number) is minimized. The use of specific signal or background features of an increased, genetically determined level of performance in assessments of varieties provides a rise in the efficiency and predictability of the selection of potentially highly productive varieties in years with unfavorable growing conditions.

Comparative analysis of parameters for two ranks of the plant performance allows evaluating varieties by their agroecological plasticity, which is largely attributed to the fact that upon transition of plants to a higher level of individual performance competition between productive shoots in distribution of plastic substances is poorly manifested. As a result of the optimal synchrony of their development, spikes of more similar length and weight are formed.

Among the spring barley varieties under investigation, according to the degree of increase in the plant performance parameters of the 2^nd rank, variety Donetskiy 14 was objectively distinguished as a variety with high agroecological plasticity.

In the study, the correlations between individual quantitative characteristics, the plant performance and yield structure parameters and the performance of the varieties under dry growing conditions were determined. The peculiarities of correlations between the yields of varieties and expression of quantitative traits of the performance show that in over 70% of cases a gain in the yield under dry conditions is provided by the ability of a variety to form a more denser productive stands per unit area, which is closely related to the adaptive potential of this variety in terms of maintenance of the ontogenetic homeostasis of plants. Selection of varieties only by phenogenetic expression of direct features of the spike performance (length, weight, grain number) does not fully correspond to the variety model with high ecological plasticity and requires account for a feasible gain in the variety yield under more favorable growing conditions.

Conclusions. The estimated indices of "specific weight of the main and conditional spikes”, "spike uniformity" in plants of the 2^nd – 3^rd ranks of performance, the EORO (efficiency of organogenesis of reproductive organs) are sufficiently effective criteria for selecting environmentally-plastic semi-intensive barley varieties with optimal yields, which would be tolerant to soil and air droughts.