Polyembryony, variation and introgression - for expanding the citrus area

Abstract

The review presents citrus as a special group of flora. It is also indicated that there are many varieties and forms of citrus crops (lemon-Citrus Limon Burm, tangerine Citrus Reticulata Bl., orange-Citrus Sinensis(L.) Osb., grapefruit-Citrus Paradisi Macf.) which is derived from the process of evolution (variation, heredity, selection), from adaptation to natural conditions and conscious selection.     

These very interesting plants, after being freed from the phytocenosis of the tropical forest, in the process of cultivation in the open ground, in completely different climatic conditions - in different regimes of moisture, soil and atmosphere, did not lose the properties characteristic of tropical plants, but as a result of natural interbreeding (which they have a noticeable tendency to) they received great biological plasticity, adaptation High resistance to low temperature, dry soil and air.

 The fact that citrus trees have gone far in terms of adapting to different thermal regimes is indicated by the data and the scale of their distribution.     

The practice of introduction to citrus crops has convinced everyone that the degree of adaptability of lemon, orange and mandarin is very high, and their promising varieties and forms can be seen in areas far from the place of origin (USA, Mediterranean coast, China, Japan, Indonesia, Europe);

In the historical process of the establishment of new forms of citrus fruits, it is striking that the way to further expansion of the area is explored not by the best forms in terms of culture, yield and productivity, but also less adapted ones too to any soil conditions, with relatively average data.

By making methodical selection, it is possible to highlight the role of citrus crops and expand the area;