COMBINING ABILITY ANALYSIS FOR HARVEST INDEX IN SPRING BARLEY CULTIVARS
Authors:   Samara Research Institute of Agriculture named after N.M. Tulaykov –  Branch of Samara Federal Research Center RAS, Dolzhenko D.O. 
Published: June 2022

Under the contrasting hydrothermal conditions of the Middle Volga forest-steppe in the system of diallel crosses (6×6) the combinative ability of three indices of barley yield index was studied: the ratio of the mass of grain per plant to plant weight, the ratio of the mass of grain from the main shoot to the mass of the shoot, the ratio of the mass of grain from the ear to the mass of the main spice. It was found that the manifestation of all the studied indicators was influenced by the conditions of the year of research and genotype. Hybrid populations on average had higher values of yield index compared to parental forms. All indices of the yield index were inherited mainly by the type of heterosis and positive dominance, while the ratio of the weight of grains per ear to the weight of the main ear, also by the type of intermediate inheritance. Effect indices and variants of general and specific combinational ability were calculated. It was found that both additive and non-additive effects were manifested in trait control, while the role of non-additive effects increased for the ratio of grain mass per plant to plant mass and the ratio of grain mass from the main ear to the ear mass in dry year, and for the ratio of grain mass per ear to the mass of the main ear - additive effects. Coefficient of heritability of plant grain weight to plant weight in broad sense (H2) was 0,70...0,82, in narrow sense (h2) - 0,47...0,51, ), ratio of grain weight of main spike to shoot weight - 0,79...0,88 and 0,44...0,57, ratio of grain weight of main spike to main spike weight - 0,88...0,95 and 0,51...0,66, respectively. It is concluded that these traits are characterized by an average degree of heritability, the selection for increasing the yield index can be successful, but the selection should begin in later generations, in any year under the conditions of moisture. The effects of the Ox correlated significantly with the expression of traits in the original parents (r = 0,75...0,89 for the parental varieties, 0,90...0,95 for the parental varieties and 0,92...0,98 for the parental varieties); therefore, selection of pairs for increasing all indicators can be conducted on the basis of their values in the parental varieties. On the basis of high values of the general combinative ability were identified valuable donors: Nutans 553 and Anna (all indexes of yield index), Margret (ratio of grain mass per plant to the mass of the plant in favorable conditions, the ratio of grain mass from the main shoot to the mass of the shoot). Also identified a number of hybrid combinations with high values of special combinative ability, from which it is possible to select promising breeding lines: Nutans 553/Margret (by all indices of yield index), Condor/Margret (ratio of grain mass per plant to plant weight and ratio of grain mass per ear to the mass of the main ear), Omskiyholozerny 1/Lun (ratio of grain mass per main shoot to the mass of shoot and ratio of grain mass per ear to the mass of the main ear), and their reciprocities. The selected varieties and hybrids are recommended for use in barley breeding programs for yield.