Breeding a grazing alsike clover for northern Bulgaria: the 2017 Pavlikeni trial
Between 2014 and 2017 a Bulgarian breeder crossed alsike clover plants from nine mostly European accessions and tested their offspring against a wild local population. Its end product was a synthetic population intended for a grazing variety.
What the study did and found
The paper is “Breeding of alsike clover (Trifolium hybridum L.) for the conditions of Central Northern Bulgaria”. It appeared in Bulgarian with an English abstract in Rastenievadni nauki (Bulgarian Journal of Crop Science) in 2017 (publisher’s open-access page). Its author, Galina Naydenova of the Soybean Experimental Station in Pavlikeni, states that no alsike breeding had been done in Bulgaria before. Eleven elite plants from nine introduced accessions were polycrossed in 2014. Their half-sib families grew in nursery rows in 2015–2017 beside a wild population from the Omurtag area.
In the second season, families 194/1, 191/1, 194/2, 154/1 and 22/1 gave more dry matter than the local check in the spring regrowth. Yield came at a price: 154/1 and 191/1 had no plants left by the third season, while 150/1 kept 85% against the check’s 75%. Survivors of five families were then crossed into a synthetic breeding population.
Why it is cited
The paper’s value as a reference lies in its content: by its author’s account it is the first alsike breeding work in Bulgaria. It documents the parents, the families and the synthetic population from which the programme meant to develop a grazing variety.
This was a small nursery test at one site, with 2 m rows, two replicates and yields in kilograms per metre of row. The wild check regrew weakly in summer, which flatters the families, and survival was compared without a statistical test. The paper also has inconsistencies: correlation coefficients are labelled r², and one accession described as European is listed in its table as from the USA.
We found no later publication on the fate of the synthetic population. No alsike variety is on Bulgaria’s 2026 Official Variety List, and the EU common catalogue of January 2023 listed 14 alsike varieties, none from Bulgaria. A 2015 review of perennial forage legumes explains why such programmes move slowly: long selection cycles, low investment and severe inbreeding depression.
The topic today
Alsike is now named in Bulgaria’s farm-support rules as the first species listed for inter-row cover in an eco-scheme for permanent crops. Lucerne dominates the country’s green forage legumes, with 93% of their area in 2024. The IPCC projects lower forage production in southern Europe at 2–4°C of warming, which matters for a clover that does not tolerate drought.
For the current picture, see our explainer Can Alsike Clover Be Bred for Bulgaria’s Lowland Pastures?.