Plant and Soil Science

Increase of adaptive response of the source breeding material of alfalfa to the growing conditions is important and allows us to fulfil the potential of feed and seed productivity of varieties of the intensive type. The aim of research was to evaluate environmental adaptability of hybrid (F3) populations of alfalfa by feed and seed productivity against a background of high soil acidity in different years of grass stand use. Researches were carried out in 2012-2016 on the fields of the Institute of Feeds and Agriculture of Podillia of NAAS. As the research material there were used 42 hybrid populations F3 created according to the complete diallel scheme involving alfalfa samples (Syniukha (UJ0700134, Ukraine), Regina (UJ0700031, Ukraine); Yaroslavna (UJ0700225, Ukraine), Vika (Denmark); Mega (UJ0700365, Sweden); Grilys (Sweden) and variable Zhydrune (UJ0700699, Lithuania). Research methods: field (phenological observations and taking records), laboratory (accounting of seed productivity), mathematical and statistical (objective assessment of obtained experimental data). By feed productivity a coefficient of environmental plasticity (bi) that exceeded one unit was found in 20 hybrid populations, but only 12 of them were at the level of the standard variety (+/- 5% or 0.06 kg/m²): Vika / Mega, Mega / Syniukha, Regina / Vika, Yaroslavna / Regina, Zhydrune / Yaroslavna, Mega / Zhydrune, Grilys / Vika, Syniukha / Regina, Vika / Yaroslavna, Syniukha / Grilys, or significantly exceeded its by dry matter yield (+9-15% or 0.1 -0.17 kg/m²): Mega / Grilys, Zhydrune / Regina. These samples will respond best to improved growing conditions and can be used for breeding varieties of the intensive type of use by this trait. When breeding for increasing the duration of productive longevity it is appropriate to select hybrid populations that in the fourth year of use had, compared to others, rather high dry matter yield – 1.41-1.53 kg/m2 that significantly exceeds this indicator in Syniukha variety by 0,16-0,34 kg/m². They are Zhydrune / Syniukha, Mega / Regina, Vika / Regina and Grilys / Zhydrune. By seed productivity, regression coefficient bi oriented to the samples with the greatest response to the growing conditions (bi>1) was found in 15 combinations. 7 of them were at the level of the standard variety Syniukha by seed yield: Mega / Yaroslavna, Mega / Zhydrune, Grilys / Mega, Zhydrune / Vika, Regina / Zhydrune, Grilys / Regina, Syniukha / Zhydrune and one substantially exceeded it by 20% (+ 7.9 g/m²) – Syniukha / Mega. The value of variance of stability (Si2 ), which ranged within rather wide margins (from 2 to 3062) indicates that the empirical values differ from the theoretical ones, that could be observed even in the standard variety under Si2 = 10. There were identified hybrid populations having a positive reaction to improved growing conditions and productive longevity by the level of feed and seed productivity during four years of use – Syniukha / Zhydrune, Mega / Grilys, Mega / Zhydrune, Vika / Mega. The value of coefficient of environmental plasticity (bi) for feed productivity ranged within 1.71-2.44 and seed productivity – 1.34-1.6, variances of stability (Si2 ) – 0.01-0.08 and 2-554 respectively.

alfalfa, plasticity, stability, environmental adaptability, soil acidity, productive longevity