PERFORMANCE INHERITANCE AND COMBINING ABILITY OF SPRING BARLEY ACCESSIONS

In 2019–2020 at the Plant Production Institute named after V.Ya. Yuriev of NAAS, features of the inheritance and combining ability for the plant performance plant traits were elucidated in 22 cultivars and three lines of spring barley. Based on this, gene interaction types and effects were determined depending on the cross combination and cultivation year, and a possibility of obtainment of transgressive segregants was proven. Depending on the year conditions, different types of gene interactions for the performance were observed in F1: from positive to negative dominance. Parents Khors and Troian showed a high general combining ability (GCA); Troian also had a high specific combining ability (SCA).

Purpose and objectives. To establish the gene interaction types in the performance inheritance, to evaluate the combining abilities and effects of genes for this trait in spring barley accessions.
Plants were crossed forcibly, from spikelet to spikelet, in 2018 and 2019. F 1 seeds and parents were sown with a cassette breeding planter SKS-6A. Grain pea was the forecrop. The plot area was 0.20 m 2 . The interrow distance was 0.20 m; the inter-plot tracks were of 0.50 m. Crossings were performed in two replications. Plants were harvested manually, with roots.
For structural analysis, 20 typical plants were chosen from each F 1 hybrid population, and the performance inheritance was determined by dominance degree (h p ) [26]. The obtained data were grouped and gene interaction types were determined as per G.M. Beil and R.E. Atkins's classification [27]. Using two-factor analysis of variance in STATISTICA 10, we found significant differences between the GCA and SCA variances for the performance and evaluated the combining ability effects.
Results and discussion. In the study years, the weather was various, allowing for comprehensive assessments of the experimental material. Thus, in 2019 during the growing period, barley made good use of precipitation in April and May, but in June and July there was a drought accompanied with high temperatures. The average daily temperature exceeded the multi-year average by 1.5-4.6°С, reaching the peak of 33.2-35.2°С in June. Such weather conditions were unfavorable for the development of barley plants and led to the formation of short spikes and a small number of lateral stems, while shrivelled grain was formed because summer droughts.
On the contrary, in 2020, the growing period had an excessively wet and cool spring. The temperature in April-May was lower than the multi-year average by 0.8-2.6°С, and the precipitation amount in May was 64 mm (147% of the multi-year average). Such weather conditions were favorable for the growth and development of barley, as they boosted its tillering and were boon to long spikes. Drought began and temperature elevated (0.8-1.7°C above the multiyear average) in June. Only during the second 10 days of July, there was a lot of precipitation (67 mm more than the multi-year average, or 368%), but this precipitation was torrential, often accompanied by hail, so it were ineffective. Thus, 2019 was unfavorable for the growth and development of barley, and 2020 can be considered as quite favorable.
Having analyzed F 1 plants in 2019, we defined the gene interaction type for the performance as positive overdominance (heterosis) in all hybrid combinations (the dominance degree h p = 1.58-191.50) (Table 1). Therefore, selections of only recessive homozygotes will be effective, while selections of dominant genotypes will not be effective.
In 2020, overdominance was also seen in most F 1 hybrid combinations, in particular for parents Ahrarii, NSGJ-1 and Scrabble, the dominancedegree was 2. was in the hybrid combinations Ahrarii/Scrabble (h p = 0.10), Herkules/Scrabble (h r = -0.24) and Merlin/Ahrarii (h p = 0.09), where additive effects of genes were manifested, so the trait value upon selections will be similar to the genotypic one, and this traitoriented selections will be effective.
In 2019-2020, the general (GCA) and specific (SCA) combining abilities for the plant performance of female and male components of crossings were determined. Two-factor analysis of variance of the F 1 experimental data demonstrated significance of the effects both of all variants (genotypes), including female and male components and F 1 , and of separate F 1 and cross components (totally and individually of female and male forms), as well as of the "F 1 -cross components" and "female-male components" interactions on the trait variability.
Through this lens, we evaluated the GCA effects of the female components and testers and the SCA effects as a result of their interaction ( Table 2).
As to the GCA effects, the studied accessions can be grouped as follows: with high, low or intermediate GCA. In 2019, the GCA was significantly high in female components Amil, Khors, Troian and Talisman Myronivskyi; in 2020, in Avhur, Khors, Troian, Reserv, Datcha, Margret and line 15-1246. For the two years, the GCA was high in cultivars Khors and Troian, i.e. they had much more genetic factors (or gene effects) that determine a high level of the trait. The GCA was high in male components Scrabble in 2019 and NSGJ-1 in 2020. That is, none of the parents had a consistently high GCA in the two years.
In  Hybrids between accessions with a high GCA and accessions with a lower or intermediate GCA may be promising in breeding due appearance of positive transgressions in the offspring.
The specific combining ability (SCA) effects were assessed in 2019 (Table 3).
In 2019, the SCA effects were significantly strong in female cultivars Troian, Datcha, Gladys, Grace, Gatunok, Modern, and Herkules and in testers Ahrarii and Scrabble, some hybrid combinations with which were better or worse than the mean values of both cross components. In the combinations Troian/Scrabble, Datcha/Ahrarii, Gladys/Scrabble, Grace/NSGJ-1, Grade/NSGJ-1, Modern/Ahrarii, and Herkules/Ahrarii, the SCA values were significantly high and heterosis was manifested. Hence, it is possible to select transgressive plants in F 2 from these populations.

Conclusions.
The study found that the gene interaction types in the spring barley performance inheritance depended on cross combinations and growing conditions. In unfavorable 2019, F 1 only showed positive overdominance (heterosis), while in favorable 2020, positive overdominance, positive dominance and intermediate inheritance were observed. In 2019-2020, the high GCA was seen in female cultivars Khors and Troian, i.e. these varieties had more genetic factors (or gene effects) that positively determine the trait level. In 2019, the strong SCA effects were noticed in female components Troian, Datcha, Gladys, Grace, Gatunok, Modern, and Herkules and male forms Agrarii and Scrabble. The hybrid combinations with the maximum probability of producing transgressive segregants have been selected. Purpose and objectives. To establish the gene interaction types in the performance inheritance, to evaluate the combining abilities and effects of genes for this trait in spring barley accessions. Materials and methods. We investigated 75 F 1 spring barley hybrid combinations derived from crossing 25 female forms with three male ones (chaffy and naked). Crossing was conducted in accordance with topcross design. F 1 seeds and parents were sown with a cassette breeding planter SKS-6A. Grain pea was the forecrop. The plot area was 0.20 m 2 . The interrow distance was 0.20 m; the inter-plot tracks were of 0.50 m. Crossings were performed in two replications. Plants were harvested manually, with roots. For structural analysis, 20 typical plants were chosen from each F 1 hybrid population, and the performance inheritance was determined by dominance degree (h p ). The obtained data were grouped and gene interaction types were determined as per G.M. Beil and R.E. Atkins's classification. Using two-factor analysis of variance in STATISTICA 10, we found significant differences between the GCA and SCA variances for the performance and evaluated the combining ability effects. Results and discussion. In 2019-2020, the features of 22 spring barley cultivars and three lines were described in terms of the gene interaction types in the performance inheritance and combining ability. On this basis, the prospects of biotype selections were evaluated. In the arid conditions of 2019, F 1 only showed positive over dominance, while in favorable 2020 the inheritance types varied from positive to negative overdominance. In the two years, the general combining ability was high in female cultivars Khors and Troian. The male components did not show consistently high GCA for the both years. Hybrids between accessions with a high GCA and accessions with a lower or intermediate GCA may be promising in breeding due appearance of positive transgressions in the offspring. In 2019, the SCA effects were significantly strong in female forms Troian, Datcha, Gladys, Grace, Gatunok, Modern, and Herkules and in male forms Ahrarii and Scrabble. Conclusions. The study found that the gene interaction types in the spring barley performance inheritance depended on cross combinations and growing conditions. In unfavorable 2019, F 1 only showed positive overdominance (heterosis), while in favorable 2020, positive overdominance, positive dominance and intermediate inheritance were observed. In 2019-2020, the high GCA was seen in female cultivars Khors and Troian. The strong SCA effects were noticed in female components Troian, Datcha, Gladys, Grace, Gatunok, Modern, and Herkules and male forms Agrarii and Scrabble. The hybrid combinations with the maximum probability of producing transgressive segregants have been selected.
Key words: spring barley, performance, inheritance, dominance degree, gene interaction type, general and specific combining abilities (GCA and SCA).