Рhenotypic manifestation of associative morphogenetic traits in single-cross sterile hybrids of winter rye (Secale Cereale L.).
Authors:   Verkhniachka Experimental Breeding Station, Mazur Z. O. , Kornieieva M. O. ,   Institute of Bioenergy Crops and Sugar Beet National Academy of Agrarian Sciences of Ukraine, Orlov S. D. ,   Institute of Bioenergy Crops and Sugar Beet National Academy of Agrarian Sciences of Ukraine
Published: February 2025

Topicality. The study of phenotypic parameters of quantitative morphological traits that associatively af-fect the productivity of winter rye plants allowed developing theoretical predictions on the effectiveness of their breeding improvement. Purpose. To determine the level of phenotypic manifestation, variability and type of phenotypic dominance of morphogenetic traits of winter rye in single-cross sterile hybrids as a maternal component and to select the best breeding samples. Material and Methods. Six cytoplasmic male-sterile (CMS) and six self-fertile sterility maintainer (SM) lines of short-stemmed winter rye determined by dominant gene hl (except for SM line 4) were studied. The study was carried out according to quantitative morphogenetic characteristics, using the methods of the State Testing of Plant Varieties for Suitability for Distribution in Ukraine. The level of phenotypic manifestation of traits of single-cross sterile hybrids in relation to the parental forms was estimated as a percentage of the pollen-sterile (CMS line) and unrelated sterility maintainer (CS), and by the assessment of the dominance of hp calculated according to the formula of G.M. Bale and R.E. Atkins. Results. The coefficient of variation in plant height was increased in 54.5 % of hybrid combinations in comparison with parental forms, in the vast majority of CMS lines and SMs this trait was classified as low-variable, 63.6 % of single-cross sterile hybrids inherited height by intermediate type and negative dominance and depression, resulting in short-stemmed plants and increased lodging resistance. The number of productive shoots is a medium- and highly variable trait (depending on the genotype), and depression was detected in 72.7 % of the combinations (hp ranged from -1.1 to -5.2). Spike length, as a trait, was characterised by low variability, and 45.4 % of the single-cross sterile hybrids inherited the trait by intermediate type and heterosis. According to the number of flowers in the spike of single-cross sterile hybrids, 36.3 % of combinations showed heterosis for this trait. Spike density was a relatively stable trait in terms of variation of phenotypic values, and 45.4 % of single-cross sterile hybrids inherited the trait by intermediate type and heterosis. According to the fertility trait, 54.5 % of hybrid combinations showed heterosis (the degree of phenotypic dominance hp was in the range of 1.0–17.0). Conclusions. It was found that the manifestation of heterosis and positive dominance in single-cross sterile hybrids in relation to parental forms expands the combinative variability of quantitative traits, which allows more efficient selection of the best pairs as components of crossing. In many cases, the inbred depression of the pollen-sterile form is eliminated, as a result of which an increase in the number of heterosis combinations in the final hybrids of winter rye is predicted.
Key words: winter rye, pollen-sterile lines, sterility maintainers, heterosis