Silvia Cappellozza
Sericultural Specialized Section of Padua - Experiment Institute for Agricultural Zoology of Florence - Ministry of Agricultural and Forestry Policies - ITALY
E-mail: <[email protected]>
15 December 2002
It seems that Black mulberry (Morus nigra) was the first species to be imported to Italy from Persia (present-day Iran), while White mulberry (Morus alba) came from the Far East. The Black mulberry has always been cultivated for its fruit in Italy, not only for food but also for medicinal purposes by the Greeks and the Romans; on the other hand, there are no precise references to the dates of introduction and expansion of White mulberry. Probably M. alba was introduced to Italy with sericulture, and thus between the ninth and twelfth centuries. The first clear and unequivocal declaration of the presence of M. alba in Italy comes from Pescia where, in 1434 Francesco Bonvicino, upon his return from the Orient, demonstrated some plants that he had brought back (Bertelli Bergamaschi, 1994). The real development, in Italy and in Europe, of mulberry cultivation with M. alba was determined by its link with sericulture, which made the cultivation of mulberry not only relevant, but also generalized throughout Italy. Despite the close interdependency with the silkworm, the mulberry has never received much scientific interest in Italy. It has been written recently: “...it is regrettable that about a plant which has for such a long time determined the Italian agricultural landscape there is still not a systematic study which follows its evolution in time” (Zanier, 1998).
The mulberry currently cultivated for its leaves to feed the Bombyx mori, is mostly M. alba, with its various varieties and spontaneous hybrids. Some of these have been present in the territory for a long time, while others were more recently (in the 1930s to 1950s) imported from the Far East (Japan in particular). From specialized mulberry cultivation (formed basically by selected varieties) plants were disseminated throughout the various regions of Italy, but the only remnants of previous sericultural activity are high trunk plants isolated or aligned along fences and roads. These are either definitely “wild” plants, thus derived from spontaneous hybridisation, or selected M. alba varieties, reproduced by scion. However, it is almost impossible to obtain a certain classification of these old trees, at least with the traditional methods based on plant phenology, both because of the different behaviour of the mulberry tree depending on the climatic environment and cultivation system and because of the fact that local names add confusion to the already uncertain taxonomy. For this reason, in Italy there are two major sources of mulberry germplasm: the cultivars preserved in mulberry collections (identified germplasm) and the plants scattered all around the Italian countryside (non-identified germplasm).
In Italy there is basically only one mulberry collection, which belongs to the Sericultural Specialised Section of Padua (abbreviated as SSSP) - Experiment Institute for Agricultural Zoology (Padua) of the Italian Ministry for Agriculture and Forestry Policies. The Institute was founded in 1871 in the centre of the city of Padua and then moved to the suburbs of the city in 1922-23. A mulberry field was planted with local varieties in those years. Nevertheless, the main part of the current mulberry collection was transported later to the Institute, at the end of the 1950s. In fact, another Institute had been founded in the centre of Italy, in the city of Ascoli at the beginning of the 20th century. When it was transformed into an Experiment Institute for the study of Horticulture, the Director, Prof. Porzia Lorenza Lombardi became the director of the Padua Institute. This was the reason why she brought the Ascoli mulberry collection to Padua. From that moment the Padua Institute became the only source of mulberry germplasm of certain origin in Italy. Prof. Lombardi was the first director that thoroughly described the mulberry varieties of the Institute. In the SSSP annals (Lombardi, 1964) she divided mulberry varieties into four groups: 1) indigenous varieties trained to a high cut; 2) indigenous varieties with low stump or bushy 3) varieties trained to high cut and imported in1934 from China and Japan 4) varieties imported from Japan in 1955. The varieties mentioned in the Lombardi’s paper are more or less the same varieties we can currently find in the SSSP collection. The Lombardi’s direction is remarkable also because before her age the mulberry was not considered to play a key role in silk production and the studies on the plant were scarce. She was an innovator, in the sense that she carried out research on a specialized kind of moriculture, i.e. mulberry trees planted in distinct parcels and not as fences or along countryside roads and pathways. For this reason, resistance to diseases, early or delayed sprouting and productivity started to be taken into account much more; for the same reason, the different Italian cultivars were evaluated for their main characteristics and new exotic varieties were imported. At that time, however, the mulberry plant was exclusively regarded as the food source for the silkworm and germplasm maintenance was carried out only with the purpose of producing new improved varieties for sericultural activity. It was only at the beginning of the 1990s that the mulberry began to be considered as a distinct entity from the silkworm and the plant itself became important in terms of preservation of biodiversity and as an important element of the agricultural landscape. Nowadays, the perception of the mulberry as an important resource for different purposes has spread in all sericultural countries and it has begun to be considered as food for livestock, as a source of medicines and cosmetics, as a fruit tree, as a fibre and cellulose producer for industrial uses. For this reason the lower the importance of the silkworm in industrialised countries the more interesting the preservation of the mulberry accessions for different objectives. Nevertheless, since usually the same Institutes that preserve silkworm collections are in charge of mulberry germplasm maintenance, the decrease in funding, which has been recorded in recent years with regard to research activity in sericulture, has also affected mulberry germplasm preservation. Italy is not an exception to this rule. But the real paradox of this situation is that many research projects on alternative uses of the mulberry were recently presented to the Italian government and gained the attention of the Ministry for Agriculture and Forestry Policies. The mulberry is an interesting species since it is a rustic plant, which in Italy grows well on flat lands, on hills and on mountains, up to the limit of the chestnut tree. Although the best vegetative development is achieved in fertile lands with discrete water sources, the mulberry also grows well in calcaric soils with good water availability. The plant prefers a temperate climate to colder areas but it can be cultivated in hot regions next to the sea or to the mountains, which have a mitigating effect on the high temperatures. For these characteristics it is suitable for the reforestation of marginal zones, and can be planted on slopes which are subjected to water erosion and other meteorological factors and in soils poor in nutrients and water, since its roots can go rather deep into the soil. Furthermore, some cultivars are salt tolerant, resistant to the most common fungal diseases and to extreme water scarcity. These characteristics may be further reinforced through the use of the selection and of appropriate biotechnologies. It is clear that in all the plans for the genetic improvement of plants and animals the most important thing is the availability of a great number of mutants for different characteristics, in order to have a working base. Thus, the first step for scientists is to know what kinds of mutants are available all around the world. Furthermore, the same type of accession may show a different phenotype depending on different climatic and environmental conditions; for this reason, some characteristics may be evident under stress situations and not under optimal cultivation methods. These considerations are sufficient to reinforce the evidence that the collection of information and the exchange of this information all around the world, are the most important things to do before initiating a plan for the multi-purpose utilization of the mulberry.
