The necessity to increase genetic diversity in agriculture has been widely discussed during the last decades.

Heterogeneous populations is one of the ways to increase genetic diversity in varieties of self-pollinating cereals. The

aim of this research was to compare grain yield, its stability, foliar diseases severity and competitiveness against the

weeds of spring barley (Hordeum vulgare) populations and homogenous varieties. Field trials consisting of three types

of populations (simple, complex and composite cro (...)

The necessity to increase genetic diversity in agriculture has been widely discussed during the last decades.

Heterogeneous populations is one of the ways to increase genetic diversity in varieties of self-pollinating cereals. The

aim of this research was to compare grain yield, its stability, foliar diseases severity and competitiveness against the

weeds of spring barley (Hordeum vulgare) populations and homogenous varieties. Field trials consisting of three types

of populations (simple, complex and composite cross populations – CCP) containing different levels of diversity and

three check varieties were carried out during 2015-2018 under organic and conventional farming systems. No one of

the populations had a significantly higher average yield than any of the check varieties. CCP1 showed a tendency to be

more productive under organic growing conditions and can be characterized as widely adaptable to various growing

conditions with a significantly higher yield as the average overall environments. One of the complex populations

showed adaptability to favorable growing conditions and yield insignificantly higher than overall average. Other

studied populations can be characterized with wide adaptability and various yield levels. For most of the populations

under organic and conventional conditions, a significantly lower net blotch (caused by Pyrenophora teres) severity

was observed in comparison with the most susceptible variety; infection with powdery mildew (caused by Blumeria

graminis) lower than for check varieties was observed under organic growing conditions, whereas such trend was

not observed under conventional conditions. All populations had a significantly lower crop ground cover and slightly

lower competiveness against weeds than the variety with the best competitiveness.