Expression and inheritance of performance constituents and seed color in winter rye

Abstract

Purpose. To establish peculiarities of inheritance of major breeding traits in lines - parents of winter rye hybrids; to assess the effectiveness of creating starting material for heterotic winter rye breeding based on lines - donors of purple seed color and a set of valuable economic characteristics.

Material and methods. The experiments were conducted in the fields of Verkhniachka Experimental Breeding Station of the Institute of Bioenergy Crops and Sugar Beet (Verkhniachka EBS IBCSB) of NAAS of Ukraine (Umanskyi District of Cherkassy Region) in 2021-2022.  The following F₁ and F₂ simple hybrids were studied: l.471 x l.44 and l.471 x l.4351H.4-1-22. F₁ hybrids were sown manually in single-row sections of 1.5 m long by wide-row method (interrow distance = 25–30 cm) to a depth of 3–4 cm in 2020. The sowing design was as follows: female form – F₁ – male form, using the female and male forms as references. All fully ripened plants were harvested with roots. For structural analysis, 25 plants of the hybrids, female and male forms were taken; they were evaluated for the following morphological features: plant height (PH), the productive shoot number (PSN), and spike length (SL). We analyzed such performance constituents as the flower number per spike (FMS), kernel number per spike (KNP), kernel weight per spike (KWS), kernel weight per plant (KWP), and thousand kernel weight (TKW). During the growing period, the phases of plant growth and development were monitored. Correspondence of the observed ratio of phenotypic classes to the theoretical one in F₂ was assessed by the χ2 test.

Results and discussion. Various forms from a genetic collection, carriers of dominant and recessive alleles of one or several marker traits were used as the starting material to explore expression and inheritance of morphological traits. Hybrid combination No. 16/17–743/18 (line 471) with purple seeds, which had been created by selection and self-pollination (inbreeding), was crossed with donors of the dominant ‘short stem’ trait with wild-type (light) color of seeds, l.44 and l.4351H.4-1-22. In F₁ hybrids, the quantitative constituents of the plant performance, in particular the productive shoot number, flower number per spike, kernel number per spike, kernel weight per spike, and kernel weight per plant were higher than the parents’ mean values. High degree of dominance indicated that these traits were inherited by dominance and overdominance. In F₂ hybrids, dihybrid segregation into genotypes with different colors was observed: purple due to pigments in the caryopsis coat, intermediate and wild-type color of the aleurone layer, with greater number of wild-type plants. The purple color of the caryopsis in the parental lines, l.44 and l.4351H.4-1-22, turned out to be recessive relative to the wild-type color, but at the same time it was dominant in l.471 / l.44 relative to intermediate color, and in l.4351H.4-1-22, on the contrary, it was recessive in relation to intermediate color. Epistasis in l.471 / l.44 was seen in the following sequence: wild-type ˃ purple ˃ intermediate, while in l.471 / l.4351H.4-1-22 the sequence differed: wild-type ˃ intermediate ˃ purple.

Conclusions. Regardless of the genotypes of winter rye lines with colored and wild-type seeds included in crossings, the purple color of seeds showed a monogenic recessive inheritance.