104(2)_str20

 

ISSN 1392-3196 / e-ISSN 2335-8947
Zemdirbyste-Agriculture, vol. 104, No. 2 (2017), p. 157–164
DOI  10.13080/z-a.2017.104.020

Response of bi-parental spring barley populations to cultivation in organic and conventional farming systems

Ieva MEŽAKA, Indra LOČMELE, Dainis RUŅĢIS, Linda LEGZDIŅA

Abstract

The organic farming sector is increasing in importance and requires varieties with stable yield and adapted to organic growing conditions. Heterogeneous populations of self-pollinating crops can potentially offer an advantage over currently used homogeneous varieties. The aim of the study was to compare yield, grain quality traits and genetic diversity in two bi-parental spring barley (Hordeum vulgare L.) populations over the course of six to eight generations. Populations were made by simple crosses, divided as subpopulations in F4 generation and then cultivated in parallel at two organic and two conventional sites for consecutive five generations. After that all subpopulations were compared in joint field trial at one organic and one conventional site to determine if they had divergent grain yield and quality properties. The genetic diversity of two subpopulations from each cross was studied in the seventh cultivation season using nine SSR (simple sequence repeat) markers.

Mixed-effect modelling showed that cultivation environment was significant for grain yield and not significant for grain quality traits. Cultivation of subpopulations derived from the two crosses over six generations concurrently under conventional and organic conditions did not significantly change genetic diversity or allelic composition as assessed by SSR markers – each pair of subpopulations from the same cross were similar in both environments with one population showing a small drift. Similar proportion of alleles contributed by each parent was observed thus indicating that none of the parental varieties was preferred by selection.

Key words: bi-parental populations, genetic adaptation, Hordeum vulgare, natural selection, SSR markers.

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