NATIVE SPECIES OF CLOVER AND TIMOTHY-GRASS IN MOUNTAIN PHYTOCENOSIS: APPLICATION IN SELECTION FOR THE CREATION OF ECONOMIC VALUABLE FORMS - Ecological Consequences of Increasing Crop Productivity - page 4

1.1 INTRODUCTION
The most important chain of the adaptive approach in selection is the elaboration of
principles and methods of phytocenotic selection, that is, the creation of competitive
cultivars capable of adapting in mixed crops in the meadow diversity of mountain
hayfields and pastures.
For the sustainable development of mountain phytocenosis biodiversity, it is nec-
essary to set up systems of environmentally differentiated cultivars of fodder crops
with tolerance to extreme and destabilizing environmental conditions. Environment-
evolutionary principles are becoming dominant in the selection strategy of fodder
crops in recent years. They are based on the theory of adaptive system of growing
plants and provide for the creation of geographically and environmentally differenti-
ated cultivars [1].
As it is known [2, 3], wild plants from natural ecosystems have such valuable traits
as longevity, frost hardiness, drought resistance, and high concentration of nutrient
elements.
The existing cultivars of meadow-pasture grasses, as practice shows, are unable to
form agrocenosis in specifi c mountain conditions, because they do not have enough
productive longevity. Recommended cultivars of red clover ( Trifolium pratense ) are
not effi cient in undersow due to low competitive capacity with native species of le-
gumes. They have low survival rate of shoots, and even those plants that have survived
do not live for long and soon drop out of the grass stand, which leads to the excessive
labor and capital costs [4, 5].
For mountain regions with complex environmental conditions, cultivars with re-
sistance to stress are needed. Such cultivars are lacking nowadays, because in Russia
the selection for potential productivity is traditionally preferred. A combination of
high productivity and environmental resistance is a hard task. Decrease of adaptation
level of modern cultivars is the result of limitation of their genetic base due to the use
of a small number of genotypes as well as long and intensive selection in the con-
stantly repeating environmental conditions.
For the long period of selection studies, we have defi ned that creation of most pro-
ductive cultivars in mountain environmental zone by well-known effective methods
which is unavailable for the cultivars of hayfi eld-pasture type, because created popu-
lations have a major drawback—the low adaptive capacity in conditions of vertical
zonal differentiation of mountain slopes. Besides, studied selection samples in one-
species crops had a minimal competitive capacity. All cultivars in selection are tested
in one-species crops. We suggest using mixed crops in the evaluation of competitive
capacity.
For the creation of competitive cultivars for mountains, phytocenosis selection
samples were evaluated in the mountains (600; 900; 1,200; and 2,000 m above sea
level), sowing selected plants in the mixture with grasses and motley grasses of the
wild fl ora.
Among gramineous plants, we have chosen timothy-grass ( Phleum pratense ), be-
cause it belongs to loose-bush plants, which have the node of bushing out on the small
depth (1-5 cm). The loose-bush gramineous plants ( P. pratense , Festuca pratensis ,
Dactylis glomerata , Arrhenatherum elatius ) have overground shoots coming out from