STARTING MATERIAL FOR THE BREEDING OF EASILY PRODUCIBLE LENTIL VARIETIES

Based on results of multi-year studies of a lentil collection, starting material was selected and proposed for the creation of easily producible varieties by the following characteristics: high seed yield (11 macrosperma sources and 25 microsperma sources), suitability for mechanized harvesting (6 macrosperma and 18 microsperma sources); improved biochemical composition and high culinary properties of seeds (3 macrosperma and 10 microsperma sources).

of the studied traits included the whole range from positive dominance to depression and was determined by combination of crossing components. It was shown that the selection of idiotypes from hybrid populations should be carried out starting with F 3 and that the harvest index was advisable to use as a selection criterion. The results of studying the created lines in the breeding nurseries of the National University of Life and Environmental Sciences of Ukraine and the National Center for Plant Genetic Resources of Ukraine are summarized.
Bean is a valuable high-protein legume, which is quite common in the global agriculture. In 2016, its area was about 31 million hectares, and the gross harvest exceeded 50 million tons [1]. In many countries, it is the main source of protein (25-28% in seeds of the best varieties), and its amino acid composition is similar to animal proteins. The genus Phaseolus L. is quite polymorphic and includes up to 230 species [2]. In Ukraine, common bean (Phaseolus vulgaris L.) is the most widespread. Despite the fact that it is a traditional crop for Ukraine, its area and yields remain rather small: 40.3 thousand hectares and 1.77 t/ha, respectively, in 2019 [3]. The spread of beans in agriculture is hindered, first of all, by the insufficient number of consistently highyielding easily producible varieties. Although 21 grain bean varieties [4] have been included in the State Register of Plant Varieties Suitable for Dissemination in Ukraine as of 2021, seed production of the crop is unsatisfactory, and the purchase of high-quality seeds for a reasonable price is currently problematic. The significant increase in demand for beans, including for further export, which has been observed recently, attests to the need to boost the breeding effectiveness. Most of modern bean varieties have fairly high potential performances, but the fulfillment of the potential is limited by low homeostaticity and high susceptibility to unfavorable environmental conditions [5], insufficient resistance to pathogens [6], etc. Given considerable climatic changes, the work of international and domestic breeding centers is aimed at exploring the global gene pool of crops, expanding the genetic variability through hybridization, refining methods for selecting elite plants, especially in arid environments [6][7][8][9]. Knowledge of inheritance patterns of qualitative and major quantitative traits, features of morphogenesis in hybrid populations in a particular environment will allow for determination of the breeding value of starting material as well as for identification of hybrid combinations and lines with a desirable set of valuable economic traits [10][11][12].
Our purpose was to determine the inheritance nature and polymorphism of the performance and traits that determine it in common bean intervariety hybrids and F 1 -F 6 lines and to identify promising genotypes, lines and accessions for further practical breeding.
Material and methods. The field experiments were carried out at the Agronomic Experimental Station of the National University of Life and Environmental Sciences of Ukraine located in the transitional part of the Forest-Steppe in 2006-2016. The soil was typical chernozem; the humus content in the arable layer was 4.58%; pH -6.8-7.0; the groundwater depth -4 m. The climatic conditions correspond to a moderate humidity zone with a recent downward tendency in the precipitation amount and an upward tendency in the average daily temperature in some months. Three hybrid combinations were studied (Table 1). F 1 -F 6 derived via intraspecies crosses of common bean (Phaseolus vulgaris L.) varieties of different ecogeographical origin (Mavkafrom Ukraine, Belko -from Yugoslavia, Niger Waly -from Austria, CDC Camino and CDC Rosalee -from Canada) were previously distinguished by a set of economically important features. The study object was peculiarities of expression and inheritance of seed productivity and suitability for mechanized harvesting as well as of traits that determine them. The breeding was conducted according to the full breeding design. We conducted multiple individual selections, starting with F 2 . Families were sown separately in wide rows (45 cm wide-space sowing) within the 2 nd ten days of May. The seeding rate was 350,000 seeds/ha. The plot area was 1.35-5.4 m 2 . Check variety Pervomaiska was sown every 15 accessions. The farming techniques were conventional for the location. When laying out the field experiments, conducting phenological observa-tions, structural analysis of plants, statistical processing of experimental data, we adhered to Ukrainian Extended Harmonized Classifier of the genus Phaseolus L., VA Yepykhov"s, NA Samaryn"s, AM Drozd et al."s, BA Dospekhov"s methods, etc. [13][14][15].
The inheritance nature of traits in F 1 was determined by dominance degree: hp = (F 1 -MP):(P max -MP), where F 1 , MP, P max -average values of traits in F 1 hybrid , parents and the best parent, respectively [as Beil GM, Atkins RE described, 16]. The heterosis level in F 1 hybrids was calculated by the following formula: [(F 1 -P max ) x 100]: P max ; the transgression frequency in F 2-4 --by the following formula: Т f = (А:B) х 100, where Т f is the transgression frequency, А -the number of hybrid plants with significantly higher value of the trait compared to the best parent, and B -the number of analyzed hybrid plants. The Lewis stability coefficient was calculated by the formula given by AA Zhuchenko [17]: SF n = HE/LE, where HE and LE are the maximum and minimum values of a trait, respectively, n -the experiment duration.
Results and discussion. As to the performance, F 1 hybrid plants of any of the cross combinations did not exceed the best varieties Mavka and Belko ( Table 1). As to the inheritance peculiarities of the performance constituents, they were determined by cross components and included the whole range from superdominance (hp = 1.1-9.4) to depression (hp = -1.5). Our results confirmed the information on the dominance of unrestricted stem growth in F 1 (hp = 1.75-9.40); the heterosis level was 16.5-31.0%. We demonstrated (Tables 1, 2) that intervariety hybridization of common bean expanded the species polymorphism, including due to the emergence of probably transgressive forms in F 2 , indicating the inheritance of major quantitative traits by polymery. The transgression frequency and their degree were determined by cross components. Thus, in the F 2 Mavka/CDC Camino hybrid population, the percentage of plants with significantly higher performance compared to the parents was 2.1; in the F 2 Mavka/Niger Waly --1.3%. No such plants were found in the F 2 Belko/CDC Rosalee population. However, the shares of plants, which were probably transgressive for the lowest pod attachment height and the "the lowest pod beak -soil surface" distance were the highest (37.9% and 37.9% vs. 9.3% and 12.0%, respectively) in this combination. In general, as the results show, the incidence of transgressive forms was also low for the traits determining the seed weight per plant. Their detection in F 2 was significantly complicated by high modification variability and heterosis, which is often observed in the second generation. The share of performance-positive transgressions in F 3 related to the number of probably transgressive forms in F 2 was 50.0% in the Mavka/CDC Camino combination and 12.0% in the Belko/CDC Rosalee combination; they were not detected in the Mavka/Niger Waly hybrid population. In F 4 , the percentage of plants that surpassed both parents in terms of performance in the Mavka/CDC Camino combination increased to 66.1%. The results of structural analysis of plants of 32 F 5 breeding lines selected by several economically important traits from 141 sown accessions indicate significant differences between them (Table 3).
By stem growth type, they are determinant plants, 40.4-70.6 cm tall (the average stem length in Mavka was 59.5±1.5 cm), with a curly top, high attachment of the lowest pod (28.0 and 15.8±0.6 cm, respectively), a compressed bush and slight branching. Among the traits determining the suitability of plants for mechanized harvesting, the greatest variability was observed for "the lowest pod beak -soil surface" distance (4.4-18.7 and 7.2±0.7 cm, respectively), as the coefficient of variation was 48.0% (range 23.3-73.7%). The average performance of plants of the selected lines varied 3.5 to 13.8 g (in Mavka it was 6.3±0.6 g) with a coefficient of variation of 21.0-74.7%. There were significant differences in the performance constituents between the lines, in particular in the numbers of productive nodes, pods and seeds per plant. It should be noted that, because of high modification variability of the traits, it is difficult to combine a high performance of plants with a high attachment of the lowest pod, compact bush and determinant type of the stem growth. The identification of genotypes by indirect (quantitative) traits and breeding indices is noteworthy [18,19].
The breeding indices (number of pods per productive node, number of seeds per pod, 1000-seed weight, harvest index) are more stable compared to the performance and its constituents (Table 3).    Under arid conditions, the harvest index, which reflects the share of seeds in the total mass of the plant, was low (0.32-0.72). The highest index was recorded in lines 128/12 and 89/12: 0.72 and 0.65, respectively. A previous study [18] demonstrated that there was there a medium to close relationship (r = 0.65-0.78) between the harvest index and performance, with much higher stability of the trait, in groups of indeterminate and determinant varieties of common bean. In the performance assemblage (performance, harvest index, Mexican index, attraction index, ratio of the number of productive nodes per plant to the total number of nodes, ratio of seed weight per plant to the internode length), it is an indicative trait at the level of intervariety pheno-typic correlation coefficients (r) of ≥0.5. Therefore, it is advisable to use this trait as a criterion for selecting more productive genotypes in the early stages of breeding.
The average yield from 28 Mavka/CDC Camino breeding lines studied in breeding nursery in years 1 and 2 was 92.8-181.1 g/m 2 . 57.1% of the accessions surpassed check variety Pervomaiska (121.8 g/m 2 ) by 15.4-71.0%. The yield stability coefficient varied 32.6% to 97.1%, indicating a weak response of some of them to changes in environmental factors. In 64.3% of the lines, the yield stability was higher than 70%, and 11 accessions had better values (81.4-97.1%) than the check variety (76.5%), including accessions giving very high yields (higher than the yield from Pervomaiska).
The created breeding material differed significantly in the growing and interphase periods, seed coat color, resistance to lodging and the most common diseases (bacterial blight, bacterial wilt, anthracnose). The selected lines of common bean were further studied in the breeding nurseries according to the full breeding design. Four lines (90/12, 156/12, 159/12, 162/12) were transferred to the National Center for Plant Genetic Resources of Ukraine as sources of economically valuable traits. Certificates of registration of gene pool accessions in Ukraine were issued for lines 162/12 and 156/12. In 2016, bush-shaped plants 162/12 with nutating tops produced a yield of 0.242 kg/m 2 for a 74-day growing period, the performance was 10.5 g; 1000-seed weight --238 g, number of seeds per pod --5.0, resistance to the most harmful diseases -5-7 points. In line 156/12, these indicators were 76 days, 190.0 g/m 2 , 9.8 g, 266 g, and 5-7 points, respectively.
Conclusions. The presented results demonstrate the prospects of intraspecies hybridization as a method to create new starting material for grain common bean breeding. It was found that the inheritance nature of major quantitative traits in simple F 1 hybrids was determined by a cross combination of genotypes and included the whole range from positive to negative superdominance. Early generation hybrid populations were highly polymorphic in the manifestation of the performance, suitability for mechanized harvesting and the signs that determine them. The selection of transgressive forms should be carried out starting from the third generation. It is advisable to use the harvest index as a criterion for selecting more productive genotypes. The breeding lines (28) based on the transgressive forms, which were detected in F 2, were studied in the breeding nurseries according to the full breeding design. Four lines (90/12, 156/12, 159/12,162/12) were transferred to the National Center for Genetic Resources of Ukraine as sources of valuable economic traits.  Purpose. To study the inheritance nature and polymorphism of the performance as well as the traits determining it in intervariety hybrids of common bean (Phaseolus vulgaris L.) and to identify promising genotypes and lines for further practical breeding. Material and methods. The intraspecies F 1 -F 6 hybrid common bean (Phaseolus vulgaris L.) combinations derived from crosses of varieties of different eco-geographical origin