Inheritance of spike productivity elements in F1 winter bread wheat hybrids
Authors: Chernobai Yu.O. , Riabchun V.K. 
Published: May 2023

Purpose and Objectives. Our purpose was to study the inheritance of the spike productivity elements by F1 hybrids from tester crosses of winter bread wheat varieties of different geographical origins.

Materials and Methods. Twenty hybrid combinations from tester crosses were studied. Field studies were conducted in 2017–2019. The experiments were laid out in accordance with the requirements of breeding field experiments. F1 hybrids and their parents were sown with a hand planter within the optimal timeframe. The row length was 1 meter; the distance between the rows was 20 cm; the depth was 4–6 cm; the predecessor was black fallow. 20 kernels per row were sown. Data were statistically processed, as B.A. Dospekhov recommended. The phenotypic dominance degree for breeding traits in the hybrid combinations was calculated by B. Griffing’s formula. The obtained data were grouped in accordance with G.M. Beil. and R.E. Atkins’s classification.

Results and Discussion. In 2018, in 50% of the hybrids, the ‘spike length’ trait was inherited by overdominance; in 2019 and 2020, this type of inheritance prevailed, accounting for 95% and 70%, respectively. Positive dominance of this train in 2018 was observed in five combinations (25%). In 2019 and 2020, this type of inheritance was observed in one combination (5%) and in two combinations (10%), respectively. Intermediate inheritance was observed in four combinations (20%) in 2018 and in three combinations (15%) in 2020. Negative dominance was recorded in the of Vodohrai Bilotserkivskyi / Arktis combination (hct = -0.9) in 2018 and in the Korovaina / Kanada combination (hct = -0.8) in 2020.

In 2018 and 2020, the ‘spikelet number per spike’ trait was inherited by overdominance in 85% of the combinations; in 2019, this type of inheritance was observed in 100% of the combinations. In 2018, two combinations, namely Korovaina / Kanada (hct = 1.0) and Vodohrai Bilotserkivskyi / Kanada (hct = 0.7), inherited this trait by positive dominance, and the Ladyzhynka / Kanada combination (hct = 0.1) - by intermediate inheritance. In 2020, one combination inherited the ‘spikelet number per spike’ trait by positive dominance (Vodohrai Bilotserkivskyi / Viglanka (hct = 0.8)); one combination - by negative dominance (Ladyzhynka / Donera (hct = -1.0)) and one combination – by intermediate inheritance (Korovaina / Kanada (hct = -0.3)).

The ‘kernel number per spike’ trait was inherited by overdominance in 70%, 95% and 55% of the combinations in 2018, 2019 and 2020, respectively. In 2018, positive dominance was observed in 20% (4 combinations) of the combinations; in 2020, this type of inheritance was observed in 10% (2) of the combinations (hct = 0.8). Intermediate inheritance of this trait was observed in two combinations (10%) in 2018, in the Korovaina / Kanada combination (hct = 0.4) in 2019 and in seven combinations in 2020. Negative dominance was not observed in any of the study years.

The “kernel weight per spike’ trait was inherited by overdominance in 75%, 100% and 95% in 2018, 2019 and 2020, respectively. In 2018, this trait was inherited by positive dominance in two combinations, namely in Korovaina / Donera (hct = 0.9) and Vodohrai Bilotserkivskyi / Donera (hct = 0.8); intermediate inheritance was observed in three combinations (Ladyzhynka / Donera (hct = 0.3), Ladyzhynka / Kanada (hct = 0.5), and Khvala / Donera (hct = 0.1) ). In 2020, positive dominance was observed in one combination (Khvala / Donera (hct =1.0)).

The ‘thousand kernel weight’ trait was inherited similarly in 2018 and 2020: the prevailing type of inheritance was overdominance - 70% (14 combinations). Positive dominance was observed in 15% (3 combinations) and intermediate inheritance – also in 15% (3) of the combinations. In 2019, the prevailing type of inheritance was also overdominance, accounting for 75% (15 combinations); positive dominance was observed in 10% (2 combinations; Dyvo / Kanada (hct = 0.8) and Khvala / Viglanka ( hcт = 0.6)) and intermediate inheritance was also observed in 10% (Korovaina / Donera (hct = 0.3), Khvala / Donera (hct = 0.4)). In addition, in that year, the ‘thousand kernel weight’ trait in the Khvala / Kanada combination (hct = -1.1) was inherited by negative overdominance (depression) (hct < -1).

Conclusions. Across the study years, overdominance was the prevailing type of inheritance in F1 hybrids for all the studied traits, specifically for the spike length (50%, 95% and 75% in 2018, 2019 and 2020, respectively), the spikelet number per spike (85% in 2018 and 2020 and 100% in 2019), the kernel number per spike (70% in 2018, 95% in 2019 and 55% in 2020), the kernel weight per spike (75% in 2018, 100% in 2019 and 95% in 2020) and the thousand kernel weight (70% in 2018 and 2020, 75% in 2019). On average across the study years, two hybrid combinations with overdominance inheritance of all the investigated traits were identified: Korovaina / Viglanka and Dyvo / Viglanka. Viglanka showed the highest combining ability.