Agriculture Reference
In-Depth Information
14.1 INTRODUCTION
About 75 percent of apple trees are grown in commercial orchards of Ukraine, and 40
percent are grown in home orchards. Past decades witness a positive tendency in apple
fruits production in compliance with a national program of horticulture development
in Ukraine approved in 2008; it is planned to increase apple orchards to 144.8 thou-
sand ha for the period up to the year of 2025 [1].
The genus
Malus
was fi rst summarized in pre-Linnaean literature by Tournefort
(1700) [2, 3]. In «Species plantarum...», Linneaus (1753) described this genus as spe-
cies of the genus
Pyrus
[4] and was later adopted by Miller (1754) as genus separate
[5]. Since then genus
Malus
Mill. Was classifi ed as a member of the family Rosaceae,
subfamily Maloideae [6].
Results of investigations done by the scientists of different countries, including
molecular genetic studies as to genus
Malus
and their closest congeners, served as a
basis for a revised classifi cation system for genus and its taxonomic position within
the Rosaceae Juss. Family [3]. Actually, the apple tree belongs to the genus
Malus
subtribe Pyrinae, tribe Pyreae, subfamily Spiraeoideae (formerly Maloideae), family
Rosaceae [7]. The present
Malus
taxonomy includes 35 accepted species names, and
13 names of infraspecifi c rank [8, 9].
Most of the wild apple species were found in the mountains of central and inner
Asia, western and southwestern China, Far East, and Siberia. Just at that spot, south-
western China and inner and central Asia are situated as the largest center of diversity
of the genus
Malus
in general [2, 10].
A wide use of grafting as the main method of growing planting materials of an
apple-tree cultivars causes the necessity to study the structural processes in callus-
es, which defi ne the joining during the process of grafting. Until now, only general
principles of the processes due to insuffi cient studying of anatomic aspect of grafting
methods are given in current horticultural literature. While studying grafted young
apple trees, special attention is paid to the place of joining rootstock and scion, which
plays a crucial role in the general movement of substances, such as ions, water, and
growth-regulating hormones, in xylem [11-13].
Fruit of an apple develops from a lower fruit-set; its pulp is formed of beyond-
carpel part of the fruit. There is an opinion, Esau [11], that beyond-carpel tissue has
appendicular origin (fl ower tube or hypanthium). Some botanists consider additional
tissue to be part of receptacle; they call the external juicy part of the fruit a skin. To
identify fruit structure and fl avor properties of fresh cut produce, we studied apple
fruits grown in the Forest Steppe Zone of Ukraine [14].
14.2 MATERIALS AND METHODOLOGY
Young trees of
Malus
domestica Borkh., of different age and grafting method, grown
in the nursery of the department of horticulture at Uman National University of Hor-
ticulture, were chosen for studying. In some variants, leading elements of the xylem
were painted with a dye using our own method.
Anatomical structure was studied according to the methodology worked out by
A.O. Hrytsaienko [14-16] and our observations made with the help of updated meth-
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