by M.Waseem Akram
Apricot is considered as a very delicious and an important fruit of the world. It is a member of the family “Rosaceae” and sub-family is “Prunoidea”. Its genus is “Prunus L” and sub-genus is “Prunophora”. Botanical name of this fruit tree is Prunus armeniaca and most of the apricots which are cultivated belong to this species. Some other closely related apricot species are P. brigantiaca vill., P. ansu Komar., P. mume Sieb., P. sibirica L., P. mandshurica and P. dasycarpa Ehrh. Apricots can be used in desserts, or in savory dishes. But one the most important thing about apricots is that the oil from apricot has a variety of admirable health benefits which is extracted from their pits, also called “kernels”. It is commonly thought to be drought tolerant because it can survive in the area with low humidity in the atmosphere. But it is badly affected by the low soil moisture conditions. Apricot is a very enviable and attractive fruit of the world but is highly limited to the areas of its adaptation for the purpose of cultivation. Chilling requirement is about, approximately from 700 to 1000 hours at or below 45oF for regular flowering and good fruit set in most of the apricot species. But there are more than a few varieties that require less hours of chilling.
Apricot tree is deciduous and is 3-10 m in height. Leaves are 5-9cm in length, 4–8 cm wide and have a curved base & a sharp tip. Fruit is rich in sugar content and has a sweet kernel which is edible with some bitterness. Fruit flesh is yellow in color and covers the stone which has a seed or “Kernel” inside. This kernel is used for the purpose of oil extraction. It blooms during the months of March and April before the emergence of leaves.
Origin and geographical distribution: According to Vavilove (1951) cultivated apricot species include three centers of origin:
1) The Chinese Center; mountainous regions of northeastern, central and western china.
2) The Central Asian Center; mountainous areas from Tien-Shan south, Hindu Kush, to Kashmir.
3) The Near Eastern Center; regions extending from north-eastern Iran to the Caucasus and central Turkey.
Vavilove suggested the Near Eastern center as a secondary center of Origin for cultivated apricot species. He emphasized on the value of mountainous regions for the demonstration of diversity in cultivated apricot plants. Different studies also indicate the some connections between some older cultivated species and wild species with mountains. Apricot reached Transcaucasian and towards West through Iran from Central Asia. These westward movements of apricot must have occurred as a result of Alexander’s move to these areas and economic, military or cultural exchanges. As a consequence of the Roman-Persian wars it is also introduced to Greece and Italy. It is also thought that it was brought about by Armenian trader to the Italy and Greece; due to which is named as “P. armeniaca”. From 1928 to 1938 Dr. Kostina and some other researchers started work to assemble the different types and species of apricot from all the geographical regions of the world. Collections of seven species and 600 cultivars and farm were made at the Central Asian Experimental Station, Tashkent and Nikitsky Botanical garden, Yalta. His conclusion was most of the cultivated forms belongs to the P. armeniaca and wild forms still present in the slopes of mountains and in forests of the western, central and eastern Tien-Shan in Tibet and in Tisinling Shan range up to the mountains of North Peaking. After extensive studies of the collections Kostina declare four main eco-geographical regions and 13 regional sub-groups for species P. armeniaca;
1. Central Asian: Fergana, upper Zervshan, Samarkand, Shahrisyabz, Horezm, kopet-dag.
2. Irano-Caucasian: Irano-Caucasian, Dagestan.
3. European: West, East and North European (zerdel or Ukaranian type).
4. Dzhungar-Zailij: Dzhungar-Zailij.
Central Asian Group is the oldest center of origin and is rich in genetic diversity. Kostin’s extensive studies support the Vavilov’s concept of origin. These eco-geographical regions will be very useful for the fruit breeders.
Apricot is cultivated in the countries; Turkey, Iran, Uzbekistan, Algeria, Italy, Pakistan, France, Morocco, Spain and Egypt.
Genetic and Cyto-Genetic: At the “INRA Fruit Research Station, Bordeaux” all-inclusive projects of apricot genetic improvement were started in 1969. A study programme was conducted on apricot and the aim of the study was to conclude the associations of genetics along with the different genotypes from various eco-geographical groups. Primers used were sixteen pairs of flanking microsatellite sequences assayed in the peach genome. Out of these sixteen primer pairs eleven were polymorphic in the cultivars that were studied and it allowed us to distinguish the every genotype from each other clearly. Several variability parameters were used for the study of genetic diversity in the population. Number of alleles that were detected was of 34 with a mean value of 3.1alleles/locus. The expected mean of heterozygosity was 0.46 and the observed mean for this was 32%. It is proven that SSR markers are an efficient tool for the purpose of the study of different genotypes and fingerprinting of different cultivars.
Breeding Objectives: There are number of objective for breeding apricot in the different areas of the world with ultimately results increased production of the world. Some major objectives of breeding are;
Ø Adaptation: apricot needs long chilling period but in most of the areas temperature fluctuates at the end of winter season which influence flowering and fruit development negatively. So this is an important area of research and breeding. Warm temperature in midwinter also affects the fruiting. So tree plants with lower chilling requirements are desirable for the cultivation and better production of apricot on a wider range of ecological areas of the world.
Ø Resistance: to different diseases is also required for good production and for the availability of fresh food over long ranges. Some other characters which are desirable along with resistance and wide adaptation are large fruit size, attractive color, free from stone, good taste of the flesh and very good quality and especially longer shelf life. Resistance to disease especially “apoplexy” (term mostly used in Europe) is very important objective for the breeders to achieve.
Ø Ripening season: in all apricot producing areas of the world both early and late ripening are enviable.
Ø Broadening genetic bases: this is required for use in future breeding programmes for the development of modern cultivars with great diversity as well as with good resistance to diseases and different stresses.
Ø Development of such apricot cultivars which produce fruits that can be shipped to longer distances as fresh, attractive and full of nutrients.
Reference – Agriculture Hunt – Apricot, Apricot Growing Guide, Fruit, Growing Guide, Apricot in Pakistan