Inheritance of fodder and seed productivity characteristics by F1 winter triticale hybrids

Аннотация

Purpose and Objectives. To characterize the inheritance of fodder and seed productivity characteristics by F₁ winter triticale hybrids from reciprocal crossings. To select promising F₁ combinations that show strong heterosis in three or more performance traits.

Materials and Methods. The study was carried out at the Department of Fodder, Grain and Technical Crops Breeding of the Institute of Fodder and Agriculture of Podillia of NAAS in 2021 and 2022. The farming techniques were traditional for the forest-steppe. Parents and F₁ were sown in a hybrid nursery using a manual marker; the interrow distance was was 30 cm; the interplant distance in the rows was 10 cm. Nine winter triticale varieties of different eco-geographical origins served as the starting material for direct and reverse crossings: Bozhych, Buzhanske, and Pavlodarskyi originating from Ukraine; Tornado, Khleborob, Soyuz, Sergiy, and Sibirskiy from Russia; and NTH 1933 from China. The heterosis degree was determined according to Matzinger et al. [15] and S. Fonseca, F. Patterson.

Results and Discussion. Analysis of inheritance in F₁ hybrids showed that the productive tillering capacity was inherited by different types, with negative overdominance (55%) and heterosis (20%) prevailing. Due to intra-allelic interactions of genes functioning in a heterozygous state only, selection of genotypes in early hybrid generations may be ineffective. However, there is a high probability of identification of transgressions of increased tillering in later hybrid generations. A combination with positive dominance, Khleborob / NTH 1933 (hp = 0.6; Ht = 3.3%; Hbt = -2.5%), is worth of special attention for selection of genotypes that would have increased tillering capacity. Combinations with negative overdominance (depression) are of little value in breeding for enhanced tillering. Our data on winter triticale demonstrated that the spike length inheritance by F₁ hybrids had a wide spectrum: 10% of hybrid combinations showed positive overdominance (heterosis), 25% – positive dominance, 35% – intermediate inheritance, 15% – negative dominance, and 20% – negative overdominance (depression). This is attributed to different geographical and genetic origins of varieties selected for crossing. It should be noted that the Pavlodarskyi / Serhiy and Buzhanske / Pavlodarskyi hybrid combinations inherited spike length by depression. That is, it is possible to select winter triticale plants with relatively short spikes but with increased numbers of kernels among the distinguished hybrid combinations. Analysis in the Pavlodarskyi / Sergiy hybrid population proved that it was possible to select genotypes that would combine a relatively increased number of kernels per spike with an increased weight of kernels per spike. In the Sibirskiy / Pavlodarskyi, Tornado / Pavlodarskyi and Pavlodarskyi / Soyuz hybrid combinations with intermediate inheritance of the “kernel number per spike” trait, it was possible to select genotypes with small numbers of kernels, but kernels were heavier compared to those in the parental forms. The Bozhych / Pavlodarskyi and Sibirskiy / Pavlodarskyi hybrid combinations with positive dominance of the “kernel weight per plant” trait had intermediate inheritance of the “productive stem number” trait, the “spike length” trait and the “kernel number per spike” trait. Selection for increased weight of thousand kernels and, consequently, for increased weight of kernels per plant will be more effective in these combinations. It should be said that it is possible to generate genotypes with elongated spikes from these hybrid combinations. Negative dominance of the “productive stem number” trait, intermediate dominance of the “spike length” and “kernel number” traits, but little positive overdominance of the “kernel weight per spike” and the “kernel weight per plant” traits were intrinsic to the Pavlodarskyi / Soyuz hybrid combination. It is possible to identify genotypes with small numbers of productive stems and kernel numbers similar to those in a parent, but with an increased weight of thousand kernels.

Conclusions. Analysis of the variability of the fodder and seed productivity traits in F₁ winter triticale hybrids established that hybrid combinations differed significantly in terms of heterosis level and inheritance type. All possible variants of phenotypic dominance, from positive to negative overdominance, were identified. For such traits as the productive tillering, kernel weight per spike, kernel weight per plant, and dry matter weight per plant, depression was noted in most combinations (55–60%).