Optimal parameters of model broad bean cultivar for the central part of the Danube plain, Bulgaria

In order to increase the productive potential of crop plants, a selection of economically valuable traits is needed, the combination of which in the breeding process will lead to the development of the desired genotype. The purpose of the present study was to establish the impact of main quantitative traits on broad bean productivity (in organic production conditions) and to select parental components with increased adaptability and stability. The experimental activity was carried out in the Institute of Forage Crops (Pleven, Bulgaria), during the period 2016-2018, with source collection of 17 accessions of broad bean. A linear equation of regression was used to determine the effect of quantitative traits on seed productivity. The optimal parameters of model broad bean plant with high seed weight was characterized by the following traits: plant height - 69 cm to 90 cm, 1st pod height - 22 cm to 36 cm, pod number per plant - 9 to 14, seed number - 22 to 35, pod length - 7 to 11 cm, pod width - 15 to 19 mm, and 100 seeds weight - from 80 g to 120 g. The obtained results showed that the traits of seed number (R = 0.72) per plant, pod number (R = 0.48), 100-seed weight (R = 0.28) and 1st pod height (R = 0.25) had the greatest and statistically significant impact on the seed productivity. Accessions FbH 14, FbH 16, BGE 032012, FbH 15, and Fb 2486 were distinguished as highly adaptable regarding seed productivity, and Fb 1903 and BGE 041470 were determined as low adaptive. Accessions Fb 1896, Fb 2486, BGE 032012 and BGE 043776 combined good adaptability with low variability and were suitable as parental components for use in the combinative breeding.