As mentioned above the Italian mulberry collection of germplasm is located in the SSSP experimental mulberry field. This mulberry field covers about two and a half hectares, but the collection takes up only a small part of this area (one parcel). The trees are old; some of them are more than twenty years old and, thus, in bad condition. Furthermore, many exemplars died after some years from their planting and they were replaced with younger plants; due to this reason the trees are not homogeneous in their height and appearance. Another problem is that a part of these plants were reproduced by graft and, for this reason, the scion belonged to the variety which was to be preserved and to be put into the collection, while the stock was generally from another variety or from the “wild” type of mulberry. Over the years, the scion sometimes died and the stock itself developed; other times the scion developed scarcely and some vigorous branches from the stock developed together, creating a mixed exemplar. Nevertheless, these plants, which are not in conformity with the original variety can only be identified by means of an accurate analysis of their phenotype by an expert. The plants of the same variety are placed together on the same row; generally for each variety four to fifteen trees are available; until a few years ago the only method to identify the plants was a strip of colour painted on the trunk; plants of the same variety were painted with the same colour (for example: all the Morettiana exemplars in red, all the Florio in green). Furthermore, a map of the parcel has always been available for the staff of the SSSP. In this map the shape of the parcel, the number of rows and the number of plants of the same variety per each row are reported; however, dead trees are not indicated. The plants, which are cultivated in the parcel, have generally a vase shape since this cultivation method was judged the most apt to obtain indications about the natural bearing of the different varieties. The parcel is not irrigated and pruning is generally carried out in springtime, during the silkworm rearing season. Organic fertilization (remnants of the silkworm beds) and urea distribution are always carried out; other fertilizers are administered in case of need. Mechanical control of weeds is carried out every year. The two ornamental varieties: Morus alba var. pendula and Morus kagayamae var. platanoide, and Morus nigra are not present in this parcel but are placed in other parts of the mulberry field. Some varieties of the collection, reproduced by cutting, have been used, over the years, to renew different portions of the mulberry field (utilized to feed silkworms). In this case they have been cultivated under the medium cut method (stump height from the soil = 60-100 cm); the different varieties are not clearly distinguishable on the spot, without the maps of every portion of the mulberry field, which were designed at the moment of planting and are currently available to the Institute staff.
The number of accessions in the collection is around 50 (including M. nigra) (see annex 1 for the complete list). The species represented are: M. alba (L.), M. nigra (L.), M. kagayamae (Koidz.), M. latifolia (Poir.), M. bombycis (K.).Varieties are both indigenous cultivars or imported ones, especially from Japan between the 1930s and 1950s. According to Lombardi’s paper, quoted above, the Chinese and Japanese cvs imported in 1934 reached Italy after a very long voyage by ship. Their condition was very bad; moreover three cvs were without labels, so they could not be identified. The names of other varieties were reported in the labels with many spelling mistakes (since their names were translated from Japanese and Chinese). In the new list of SSSP accessions, recently published in the proceedings of the FAO electronic conference “Mulberry for animal production” (Cappellozza, 2002), these names were corrected according to the spelling reported in Machii’s paper (Machii et al, 1999) for the same varieties preserved in Japan. However, doubts remain about the correct interpretation of some of the names.
Two seasonal workers take care of the mulberry field and of the collection. Furthermore, a technician is responsible for the cultivation, maintenance and reproduction of the collection and the supervision of the work is carried out by the SSSP director. (Currently Dr. Luciano Cappellozza)
Contact details: Dr. Luciano Cappellozza, Sezione Specializzata per la Bachicoltura di Padova, Via dei Colli, 28 - 35143 Padova - Italy. Telephone number: +39 049 620205; Fax number: +39 049 623119; e-mail: [email protected] <mailto:[email protected]>; [email protected].
Recently a finalized project “Vegetal Genetic Resources of the Institutes for Research and Experiments in Agriculture” has been financed by the Italian Ministry for Agricultural and Forestry Policies and coordinated by the Experiment Institute for Fruit-culture. This project has the aim of conserving, characterising, documenting vegetal bio-diversity, and promoting its possible uses. Fifteen Institutes are participating to the project and the SSSP is one of them. The project started in 2000 and it will last at least for three years. The objectives of the project (with regard to the SSSP) are: Conservation and possible enrichment of the current mulberry germplasm collection, Updating of the data and information on the accessions in the collection
Integration of the database on the existing collection with new descriptors, in order to participate in the “European Plant Genetic Resources Information Infrastructure” (EPGRIS) project to create a research engine specific for European vegetal genetic resources, promoted by the UE; 36 Countries will participate in this project, in addition to the IPGRI (International Plant Genetic Resources Institute).
In the framework of this project the status of the collection has been ameliorated. Multiplication of the varieties belonging to the collection by cutting and their replanting in an empty parcel of the mulberry field were carried out. A map of the parcel was drawn and, after one year, the parcel was checked in order to record the dead trees on the same map. The saplings were marked with plastic labels where the names of genus, species and variety are reported. The plants were trained according to the medium-cut shape, fertilised and irrigated to help them overcome their juvenile phase. A new survey on the plants belonging to the old historic collection of the Institute was carried out; uncertain and dead exemplars were marked on the map and new labels were put on the trees’ stumps, in addition to the coloured strip already painted on their barks in order to identify them (see chapter 2.1). Furthermore, two volumes and one CD on the 15 Institutes’ accessions were published (Sartori et al., 2001). The publication includes a part (vol. I, pages 633-638) regarding the mulberry collection of the SSSP.
This finalized research project, which is also funded by the Italian Ministry for Agriculture and Forestry Policies, is a complex one, and includes different branches of research on the silkworm and the mulberry (see later for more details). In the framework of this research the SSSP collaborates with and co-ordinates different research units. Since it appeared to be important to check mulberry behaviour in different climatic environments, studies were carried out both in the Northern part of Italy (Padua, Venetia), and in the Southern part (Crotone, Calabria). In Calabria, in fact, there is another mulberry collection, established from Padua’s germplasm bank, which has been mostly addressed to leaf production for silkworm rearing. It belongs to the Regional Agency for Research and Experiments in Agriculture of Calabria. This Agency has two sericultural model farms; the first is in the hilly zone (S. Marco Argentano), where mulberries are planted on the slopes, while the other is in a flat zone near the sea (Mirto-Crosia). Different mulberry varieties are planted in rows; original planting was first carried out around thirty years ago, but the trees have been continuously reproduced by cutting and renewed when necessary (see annex 2 for the complete list of accessions). Some confusion among different varieties arose also in this case, and on the occasion of the project a new survey of the varieties was carried out on the basis of their phenological aspect. However, for some varieties there is no certainty about their genetic origin. A partial duplication of the SSSP collection is planned for the coming year, with the following objectives:
1) Conserving the accessions in a different place in order to avoid accidental loss of vegetal biodiversity due to unexpected causes.
2) Studying the agronomical and morphological characteristics under different climatic conditions.
Person in charge of the of the collection: Dr. Antonio Morelli, A.R.S.S.A., C.S.D. Mirto Crosia, Contrada Pantano 87060 Mirto Crosia (CS) Italy. Tel. +39 0983 42235; fax: +39 0983 480832; E-mail address: [email protected]
Many Italian Provinces and Regions focussed on the very close links between agricultural land use and the responsibilities of governments and citizens for conservation and sustainable use of biological diversity. Aware that the loss of biological diversity on much of Italian farmland is largely a result of the continuing decline in traditional, extensive and mixed farming practices, of the intensification in agriculture and of the abandonment of farming in certain regions, they therefore consider urgent the action to preserve biological diversity. For this reason, Provinces where sericultural tradition has been very strong are very interested in recovering their old local mulberry varieties. A project of this kind has already been started in the town of Meldola (Forlì), where a particular strain of Bombyx mori was reared in the past and some Morus local varieties were developed. In the framework of this project, which is carried out under the supervision of the SSSP, some old exemplars of mulberry trees, scattered in the countryside were identified and their leaves were analysed both by means of chemical laboratory analyses, and by the more advanced techniques of DNA analyses; the aim of this work is to establish if the varieties are genetically similar to others, already conserved in the SSSP collection, or if they are different. Furthermore, through the chemical analyses of the leaf, their nutritive value for silkworm and livestock is subjected to evaluation. The work is currently in progress and the first results will be obtained within the end of this year (2002).
As previously mentioned, apart from the mulberry resources that are abandoned in the Italian farmland, the other resources are strictly controlled by the SSSP in the Northern part of Italy and by the Agency for the Research and Experiments in Agriculture in the Southern part of Italy (always under SSSP supervision).
The finalized project “New technologies to relaunch Italian mori-sericulture” has provided funding, which has been partially utilized to characterize, evaluate and study the mulberry accessions of the SSSP.
First of all, ten cultivars (cvs) were chosen, which were judged interesting for their production or leaf quality, and their morphology and phenology have been studied. Research of this kind has already been carried out in the past, but often with inadequate methodology; in addition, it appeared to be worthy of study how recent and dramatic climatic seasonal variations, which have been continuously recorded also in Northern Italy, affect mulberry phenology. As a result of this study a descriptor (limited to these ten cvs) was produced and the mulberry phenological phases have been related to the climatic conditions (on the basis of a three year-study). Moreover, a lot of photographic material, mostly on leaf morphology of the different cvs under microscope observation was produced and recorded on a CD. The study on the morphology of the abaxial surface of the leaf was particularly significant. Differences in the cvs were found with regard to trichome quantity and also to the quality of the wax deposits on the leaves. The cuticle morphology of the epidermic cells also permits the discrimination among the different cvs. Furthermore, hairs on reproductive structures, such as inflorescences, are a useful characteristics to differentiate varieties. On the other hand, observations that have been performed on the infructescence, bud, pollen and seed morphology showed that the characteristics related to these organs are very similar or even identical in all the cvs. Sex of the inflorescences and number of stoma/sqcm appear to be mostly influenced by environmental conditions.
A second part of the research regarded the chemical characterization of the mulberry leaf of the different cvs, in different environmental conditions (North and South of Italy) and in different periods (from May to September). This analysis is an interesting premise to a correct use of the different cvs in various situations and during the complete vegetative period, both for silkworm rearing, and also with the objective of evaluating mulberry utilization for animal nutrition. Furthermore, chemical analysis of the leaf was combined with tests “in vivo” on silkworm larvae, by means of introduction of leaf samples in the artificial diet.
Cvs were also examined from an agronomical point of view, with the objectives of studying their adaptability to produce under rain-fed regimen or in irrigated conditions. This kind of study was also carried out with the use of chemical analyses, tests “in vivo” and quantitative assessment of leaf and wood production. Moreover, the incidence of fungal diseases in the different cvs, under irrigated or non-irrigated conditions was recorded.
The most representative cvs are also under examination for some aspects of their behaviour with respect to agamic propagation. In fact, some cvs are more suitable than others for micro-propagation and, in addition, their requirements are different, with regard to culture media, hormonal levels and ideal number of sub-cultures. Some cvs seems to be more inclined to develop mutations when kept for some times in sub-culture. Saplings derived from successive subcultures of various cvs were planted in the field and they have been observed to establish their variety conformity with mother plants. Some differences have already been recorded and samples have been collected which will undergo genetic analyses of their DNA (AFLP-based fingerprints).
However, the most innovative research foreseen in the project framework concerns the genetic characterization of all the cvs of the SSSP collection. This study deals with the use of AFLP-based fingerprints as a tool for estimating genetic variability within, as well as among the different mulberry species preserved in the SSSP collection. Results concerning genetic diversity and similarity statistics are reported and the information inferred on the origin and domestication of naturalized mulberry genotypes is discussed in the paper Botton et al., 2002. Another article has recently been submitted for publication.
With regard to the resource utilization, the SSSP has the institutional duty of distributing biological vegetal material to all Institutions or private companies, which need mulberry saplings of certified origin and free from diseases. The SSSP itself has facilities in order to multiply the mulberry plants by cutting, so it can produce limited amounts of plants. Nevertheless, generally it collaborates with private plant producers, if a remarkable number of saplings is required. Cuttings are established from mother plants and they are, thus, given to private nurseries for rooting and field acclimatization; alternatively, materials for micro-propagation can be prepared.
Apart from small-scale projects of sericulture, mulberry varieties are generally required by private plant producers for ornamental aims (private gardens, public gardens, fences along roads) or for fruit. In this case, however, it is remarkable that very few accessions among those preserved, have been selected for fruit production. Often there are requests for mulberry germplasm material from developing countries, which want to set up a sericultural activity or by countries already involved in sericultural production and that want to ameliorate their leaf production. For example, cuttings have been quite recently given to the INRA (Lyon), in order to establish a mulberry field in Le Pradél (France), in the framework of the project “Eurochrisàlide”.
As previously reported a great interest in the mulberry as a resource for multi-purpose utilization is gradually increasing. Recent crisis in livestock production due to bovine spongiform encephalopathy (BSE), which caused serious economic damage also in Italy, highlighted the need to search for natural and genuine proteic sources, alternative both to powdered animal skeletons and to the soybean, which mostly comes from transgenic crops. A finalized project entitled “Vegetal meals” is about to be approved by the Italian Ministry for Agriculture and Forestry Policies; the research will include studies on herbaceous and arboreous species that can be used to produce proteins for animal nutrition. Studies on mulberry cvs of the SSSP collection are foreseen, because the SSSP itself will be a research unit and it will collaborate with animal breeders to find out which cvs are more indicated for animal nutrition. In this context, the collection of new mulberry germplasm, its description, evaluation and exploitation represent a possibility to take into consideration.
Moreover, another research project was presented to Italian Regional Authorities. These Authorities, in fact, can finance specific research plans which are considered important for their own territories. The project concerns the multi-purpose utilization of mulberry for uses other than animal nutrition (already considered in the above-mentioned “Vegetal meals” finalized project). The proposed uses are: fruit, pharmaceutics and cosmetics, wood and fibres for industrial purposes, reforestation and landscaping, and silk. Regions that declared their interest for the project were Venetia, Lombardy, Tuscany, Calabria and Sicily to date, but others could be involved later on. Project approval is now in progress and the SSSP direction hopes it will be operative at the end of 2003. Also in this context, the SSSP mulberry collection could be exploited; moreover, other accessions could be found in the Regions mentioned above.
Currently no work is in progress concerning the evolution of new mulberry germplasm entities; in fact the breeding work and selection concerning arboreous plants is very long and demanding. Since no project has been financed in this regard, the SSSP has no available resources for this purpose. However, if the above-mentioned research projects are definitively approved and funded, this kind of research will also be carried out with the help of the University of Pisa.
