GEORGIA

Research Project

Title: Breeding new species and varieties of walnut through hybridization of different species and varieties

Project objectives: To create through hybridisation new highly fertile early-maturing cultivars of walnut (Juglans regia), characterized with late bud break, yielding high-quality harvest and resistant to inappropriate environmental conditions.

Project summary and results: During the last 30 years we have studied the gene pool of walnut in Georgia and selected the best varieties and clones of Juglans regia species. Collection orchard has been planted. Meanwhile, different varieties of walnut (J. regia), as well as planting material of various species (J. nigra, J. Major, J. rupestris, J. hindsii, J. Sieboldiana) were imported from Bulgaria, Moldavia, the Russian Federation and Uzbekistan in order to grow saplings with the aim of their further hybridisation with J. regia.

Crossbreeding was performed within Juglans regia species (Aragvi) x (Ideal). Aragvi is a local variety, characterized with high-quality yield and intensive growth. It was crossbred with Ideal, a weakly growing walnut variety. Twenty hybrid plants obtained from this interbreeding are already three years old; they are planted at the experimental base of the Institute of Tbilisi. Here are also planted 6 hybrid specimens, obtained by interbreeding of varieties within J. regia species. One of them is characterized by late bud break, one by lateral fruiting and other by clustery fruiting.

This year we have transplanted here biennial sapling of 3 cultivars of J. regia species (15 plants each) for further observations.

We plan to interbreed different species to obtain new interspecific hybrids.

Related publications: Not specified

GERMANY

Research Project

Title: Breeding, selecting and preservation of walnut varieties (Juglans regia L.)

Project objectives: In 1920 walnut research was started at the research station in Geisenheim. E. Schneiders (†1972) explained the direction of his work with the visibility and validation of national origins and initiated examinations for their propagation. He developed grafting methods like patch budding and the winter bench grafting. From 1949 K. J. Maurer (†1976) continued this work with testing the rootstock qualification of different Juglans species (J. regia, J. nigra, J. cinerea, J. sieboldiana, J. microcarpa). He also proceeded the selection work with valuable clones, so that there was formed the 'Geisenheimer Walnut assortment' till 1975. Since that time the fundamental varieties, which were suggested for production in Germany, were G. 26, G. 120, G. 139 and G. 1247. From these and other cultivar clones a scion orchard exists in Geisenheim to deliver nurseries with a good quality of propagation material. H. Jacob did continue this work since 1980 on a reduced level. Beside the preservation of the 'Geisenheimer assortment' and the visibility of new varieties of foreign countries there was a bit of new breeding work initiated. The aspired targets are late leafing, disease tolerance, quality nuts and climatic robustness. Furthermore the Institute is looking for new methods of effective propagation.

Project summary and results: With the variety "Wunder von Monrepos" (syn. Geisenheim Wonder) it was succeeded to get a qualitative brilliant nut with the best yielding capacities and high hardiness against Blight and Anthracnosis. It is also suited for climatic unfavourable areas because of its late leafing and the predominantly apomictical fruit formation.

The clone Geisenheim 1-17 shows a lateral fruit formation and counts as an interesting clone for more breeding.

It was managed to develop an effective and fast propagation method for walnuts in sheltered conditions with a modified method of green grafting (green-segment-grafting).

Related publications:

ANONYM, 1960. Deutscher Nusskatalog. Arbeitsgemeinschaft Schalenobst, Geisenheim 1960.

MAURER K. J., 1968. Schalenobst Anbau. Verlag Eugen Ulmer, Stuttgart.

SCHNEIDERS E., 1948. Der neuzeitliche Walnussanbau. Verlag Eugen Ulmer, Stuttgart.

GREECE

Research Project

Title: Evaluation of thirteen walnut (J. regia L.) seedlings selections from central Greece

Project objectives: Evaluation of thirteen (13) walnut seedlings selections, into one collection with control varieties. The best selections will be used as parents in variety breeding programs.

Project summary and results: This material is the result of walnut seedlings prospections in central Greece region (Ftiotide, Eurytanie, Fokide), in the frame of one national project.

These prospections were carried out between 1986 and 1989 and the selection criteria were: fruit and kernel quality, tolerance to bacterial blight.

From this survey of 1986-1989, twenty-seven seedling trees were selected in central Greece. Thirteen among of them, which were the most interesting and cherry leaf roll virus-free, were planted into an experimental collection. Observation from this collection has shown that: seven seedlings had an early bud break (EK1, FK3, FOPAN2, FK1, FK2, FOPAN1, FM16), while six seedlings had a mid-early bud break (FK5, FM6, FM5, FM3, FM4, FOKA1). Seven selections had a protandrous blooming (EK1, FK1, FK3, FK5, FM3, FM4, FOPAN1), two selections were almost homogamous (FOKA1, FOPAN2) and four had a protogynous bloom date (FM5, FM6, FK2, FM16). Four trees (FM6, FM5, FK1, FK5) presented some lateral bearing. Seven trees (FM3, FM4, FM5, FM6, FK3, FOPAN1, FOKA1) bore very big nuts with an average fruit weight from 18g (FOKA1) to 25g (FM3) and a percentage of kernel from 42% (FK3) to 51% (FOKA1).

Related publications:

ROUSKAS D., KATRANIS N., ZAKINTHINOS G., ISAAKIDIS A., 1997. Walnuts seedlings selections in Greece. III International Walnut Congress, 13-16 June 1995, Alcobaca, (Portugal). Acta Hort. 442:109-116.

Research Project

Title: Evaluation of seventy Greek walnut (J. regia L.) seedling selections

Project objectives: Evaluation of seventy (70) walnut seedling selections into one collection with control varieties. The best selections will be used as parents in variety breeding programs.

Project summary and results: Seventy walnut (Juglans regia L.) selections of Greek seedling populations were collected, grafted on rootstock (Juglans regia L.) and planted in a national germplasm for adaptation and evaluation studies.

This material is the result of the prospections all over Greece, in the frame of the CAMAR CT 90-0023 project supported by the European Union.

These prospections were carried out between 1991 and 1995 and the selection criteria taken into account were: date of bud break, lateral bud fruitfulness, fruit and kernel quality and tolerance to bacterial blight.

Five years preliminary observations on bud break showed that: sixteen (16) selections are very early, twenty seven (27) early, twenty three (23) are middle early and the last four (4) moderately late. In the same period the observations on blooming date showed that: there are two (2) homogamous selections, twenty one (21) protogynous, thirty four (34) protandrous and thirteen (13) selections had no catkins appearance yet. Referring to lateral bearing trait, a percentage of 35 % of these selections show lateral fruitfulness. Sixteen selections of those presenting lateral fructification gave sizeable nuts (16,1 - 24.0 gr) and high kernel percentage of (47.1 - 55.0 %). The lateral bearing selections S1-A, S34-A, S1-B, S4-B and S14-B are more promising.

Related publications:

GERMAIN E., ALETA N., NINOT A., ROUSKAS D., ZAKINTHINOS G., GOMES-PEREIRA J., MONASTRA F., LIMONGELLI F. 1997. Prospections réalisées dans les populations de semis de noyer d'Espagne, de Grèce, d'Italie et du Portugal: caractérisation des populations et description en collections d'études des présélections issues de ces prospections. Options Méditerranéennes, série B, 16: 9-40

ROUSKAS D., ZAKYNTHINOS G., 1999. Preliminary evaluation of seventy walnut (Juglans regia L.) seedling selections in Greece. Fourth International Walnut Congress, 12-16 September 1999, Bordeaux (France). Acta Horticulturae, 544: 61-72

HUNGARY

Research Project

Title: Walnut breeding

Project objectives: Breeding of new walnut varieties characterized by earlier fruiting, higher yield, lateral bearing, better reliability in fruiting (late bud break), good adaptability to different ecological conditions and good fruit quality.

Project summary and results: In the first period three most valuable local varieties have been selected from six million of Hungarian walnut trees in the framework of a national local variety selection program. These 3 main varieties are registered on national variety list, and they are named as Alsószentiváni 117, Milotai 10 and Tiszacsécsei 83 according to their place of origin. From the years of 1960th six newer candidate walnut varieties have been produced by cross breeding where Californian, French and Mandshurian varieties were used as parents with homelocal varieties.

Related publications:

SZENTIVÁNYI P. 1958. Magyar diópopulációk tulajdonságainak információs elemzése és a fajták minõsítési módszere. Kert. Kut. Int. Évkönyve. III.: 3-45.

SZENTIVÁNYI P. 1990. Breeding early fruiting, high producing walnut cultivars, leafing after late spring frost. 1st Intern. Symp. on Walnut Production, Budapest (Hungary), sept 1989. Acta Hort. 284: 175-184.

SZENTIVÁNYI P. 1990. Effect of fertility auto-regulation on productivity of walnut. 1st Intern. Symp. on Walnut Production, Budapest (Hungary), sept 1989. Acta Hort. 284: 251.

IRAN

Research Project

Title: Collection, identification and genetic conservation of Persian walnut elite trees in Fars Province

Project objectives: This study was carried out to identify the elite trees of Persian walnut (Juglans regia L.) in Fars Province.

Project summary and results: The Persian walnut populations were evaluated during 1993 and 1994 and 101 elite trees were selected in different areas of Fars Province. Considerable genetic variability was found within the populations of Persian walnut trees grown from seeds. The most important characteristics of trees which were evaluated were the date of leaf bud break, lateral bud flowering, vigour, tree shape and nut qualities: including the morphology of nut, the average shell weight, the average kernel percentage, kernel quality and the average nut length and diameter. Some elite trees with high nut quality were identified and could be recommended for mass propagation. Correlation analysis showed that a positive and significant correlation existed between the average nut weight and the average nut length and diameter, the average shell weight and the average kernel weight. Kernel percentage showed a negative and significant correlation with the average shell weight and the average kernel weight. Its correlation with the average nut weight was negative and significant.

Related publications: Not specified

Research Project

Title: In vitro culture of Persian walnut (Juglans regia L.)

Project objectives: The aim of this research was to develop tissue culture technique for rapid and mass propagation of Juglans regia L.

Project summary and results: Excised embryos of mature seeds, nodal segments and shoot tips of seedlings were used as explants. Driver and Kuniyuki walnut (DKW) medium solidified with 2.2 gl-1 Phytagel was found optimum for shoot multiplication. Performance of explants was better on DKW medium than on MS and WPM, and media solidified with Phytagel was significantly better than with Difco Bacto agar. Shoot multiplication occurred on medium containing 1.0 mgl-1 BA and 0.01 mgl-1 IBA, although 0.6-0.8 mgl-1 BA were also successful, and utilisation of 0.4 mgl-1 BA and 0.01 mgl-1 IBA was best for shoot elongation. Application of different kinds of auxins (IAA, IBA and NAA at 0.01 or 0.1 mgl-1) with 1.0 mgl-1 BA did not show any significant difference for shoot multiplication, but the morphology of shoots on 0.01 mgl-1 IBA was the best. Sucrose was found to be better than fructose and glucose for walnut shoot multiplication and inclusion of 30 gl-1 sucrose was better than 40 gl-1. A four-week subculture interval was necessary for good quality of shoots, and explants, which were in culture for more than four weeks, developed chlorosis and deficiency symptoms. The growth of Persian walnuts under photoautotrophic conditions was unsucessful. The explant morphology was affected by the environment: leaf surface and petiole length increased, shoot elongation and number of leaves decreased, but the diameter of stems increased and changed to brown. Under photoautotropic conditions in hormone free medium growth was very slow and inclusion of BA and IBA or NAA was necessary. Inclusion of 1.0 mgl-1 GA3 improved the shoot elongation of explants. The rooting of explants under photoautothorphic condition was unsuccessful. Callus was induced from leaf discs and stem internodes on DKW medium supplemented with 2.4-D, IBA and NAA. No embryoenesis or shoot organogenesis was obtained in this study using leaf discs, or callus samples originating from leaf discs, on media containing different combinations of BA, TDZ, kinetin, 2.4-D, IBA, casein hydrolysate and glutamine, in dark or lighted conditions. However, root formation was observed in darkness on media containing low concentrations of 2.4-D. The best procedure for rooting consisted of two phases: in vitro root induction and ex vitro root development. For root induction the most efficient method was utilisation of DKW medium (half strength macronutrients) solidified with 2.4 gl-1 Phytagel, containing 30 gl-1 sucrose and 4.0 mgl-1 IBA in dark conditions. For root development, shoots were transferred from root induction medium, washed with tap water, planted in moistened Jiffy-7 pots, sprayed with 1.0 gl-1 Benomyl solution and placed in a propagator with 90-95% relative humidity in lighted conditions. Using this method about 83% of shoots rooted. After root development and acclimatation, pantlets were transferred to larger pots containing bedding compost with NPK fertilisers and transferred to a greenhouse. The survival rate was more than 90%.

Related publications:

SAADAT Y.A., HENNERTY M.J., 1997. The effects of different media ans gelling agents on shoot multiplication of Persian walnut. Irish Botanists+AJI Meeting, University College Galway, Galway, Ireland.

SAADAT Y.A., HENNERTY M.J., 1998. The effects of different carbon sources and auxins on in vitro shoot multiplication of Persian walnut (Juglans regia L.). Irish Botanists+AJI Meeting, University College Dublin, Dublin, Ireland, p23.

SAADAT Y.A., HENNERTY M.J., 2001. The effects of different in vitro and ex vitro treatments on rooting performance of Persian walnut (Juglans regia L.). 4th Intern. Walnut Symposium, 12-16 September 1999, Bordeaux (France). Acta Hort., 544: 473-480.

Research Project

Title: In vitro propagation of Persian walnut (Juglans regia L.)

Project objectives:

1. Increasing shoot proliferation rate of Juglans regia in vitro

2. Rooting and acclimatization study of explants

3. Regeneration of walnut somatic tissues

Project summary and results: During six years many experiments have been conducted for disinfestations of explants, finding the best situation for excising the explants, time of excising the explants, optimising the proliferation medium for producing many vigorous shoots during a short time. For optimising the proliferation medium, nitrogen and carbon sources as well as gelling agent were investigated. But, rooting and acclimatization studies have remained to be done.

Related Publications:

VAHDATI K., KHALIGHI A, 1998. Effects of some growth regulators and complementary nitrogen compounds on in vitro shoot proliferation of Persian walnut. 25th Intl Horticulture Congress. 2-7 August. Brussels, Belgium.

VAHDATI K., KHALIGHI A, NADERI R; 1996. Effects of some plant growth regulators on in vitro shoot proliferation of Persian walnut. 1st Horticultural Science Congress of Iran. 14-17 September. Karaj, Iran. Iranian Journal of Agricultural Sciences, 29 (31): 599-606.

ZAMANI Z and VAHDATI K, 1998. Influence of carbohydrate form and nitrogen source on growth of Persian walnut shoots in vitro. 4th Intern. Walnut Symposium. 12-16 September, Bordeaux, (France). Acta Hort. 544: 537-541.

Research Project

Title: Persian walnut stooling in Iran

Project objectives:

1. Vegetative propagation of Persian walnut and producing own-root clones

2. Making a model for rooting of Juglans regia

Project summary and results: Influence of different concentrations of auxins as well as mounding and ringing treatments on rooting of walnut layers were investigated. Concentrations of 5000 and 7500 ppm of equally mixed IBA+IAA+NAA plus mounding with the mixture of perlite and sand (2:1) and wiring the base of the layers led to the most number and longest roots. The rooted layers lined-out to the second nursery successfully. Following this research work, another experiment was conducted on horizontal stooling of Juglans regia, which results have not been published yet.

Related publications:

VAHDATI K., KHALIGHI A, 1998. Persian walnut stooling in Iran. 4th Intern. Walnut Symposium. 12-16 Sept. Bordeaux, France. Acta Hort., 544: 531-535

Research Project

Title: Evaluation and identification of promising walnut genotypes in Kerman province

Project objectives: For identifying and introducing the promising walnut genotypes in Kerman province where is found one of the biggest populations of Persian walnut in Iran. The studied regions included Rabor, Baft, Bardsir, Zarand, Rayen, Sardoyeh, Deh-Bakri.

Project summary and results: From starting year of this project, 195, 113, 108 and 51 trees were identified in each year respectively and finally 51 genotypes were selected as promising genotypes. The identifying characteristics were tree shape, tree vigour, type of fruiting, time of bud break, time of pistil receptivity, time of pollen shed, dichogamy, frequency of catkins, nut maturity date yield, date of leaf-fall, blight susceptibility, winter hardiness, nut weight, nut shape, nut integrity, adhesion of shell to hull, shell thickness, kernel weight, adhesion of shell to kernel, kernel size, kernel colour and kernel percentage.

Among the studied genotypes, 37 % were lateral bearing (with more than 50 %), 25.5 % were homogamous and 52 % were high productive. 51% of these genotypes have oblate nut shape. Moderate positive correlation was found between time of bud break and type of fruiting (r=0.546). Kernel colour was influenced by yield and time of nut maturity. Because most of these genotypes were more than one 100 years old, they have to propagate vegetatively and they will have to be compared in a selection block in the future, too.

Related publications: Not specified

Research Project

Title: Evaluation and identification of promising walnut genotypes in Chahar Mahal va Bakhtiari province, Iran.

Project objectives: For identifying and introducing the promising walnut genotypes in Chahar Mahal va Bakhtiari province where is one of the populations of Persian walnut in Iran. After identification, these genotypes will be compared in a selection block to release cultivars.

Project summary and results: Using information of walnut growers and suggestive characteristics in walnut descriptors, preliminary selection will be done. After labelling some of the best trees, the collection of the characteristics has been started and later promising genotypes will be transferred to the selection block. Because this project is in the first steps, there are no publishing results yet.

Related publications: Not specified

Research Project

Title: Pistillate flower abscission in walnut (Juglans regia) and effect of high pollen load on it

Project objectives: During 1996-97, occurrence and extent of pistillate flower abscission (PFA) of the Persian walnut (J. regia L.) and role of high pollen load on PFA were investigated at the walnut genotypes collection in Karaj. Also some observations were conducted in 1997 for PFA occurrence in walnut genotype collections of Mashhad, Shahrood and Urmieh.

Project summary and results: PFA occurred in a very high level at all orchards with considerably different levels among genotypes. The average PFA of the same genotypes significantly differed among sites and years. No relationship was found between the extent of PFA and nutritional conditions as indicated by standard midsummer sampling. Low positive correlation was found between PFA and pistillate flower density (r=0.43), flowering index (r=0.3), catkin density (r=0.3).

The pollen of Shinovo genotypes was applied to unbagged flowers of ten Persian walnut genotypes. The PFA extent on the high pollen load treated flowers was significantly higher than the open pollinated flowers while the control flowers dusted with talc powder had a low PFA. Mean of pollen grains count among open-pollinated flowers indicated that PFA-type flowers of G5 and G10 genotypes had received 190 and 177 pollen grains, respectively while the normal flowers of these genotypes had 110 and 87 pollen grains, respectively.

Related Publications:

MORADI H., 1998. Study of pistillate flower abcission in walnut (Juglans regia L.) and the effect of high pollen load on it. MSc thesis. Department of Horticulture. Faculty of Agriculture. University of Tehran. Karaj, Iran.

ITALY

Research Project

Title: Evaluation of the performance of Italian and foreign walnut cultivars and selections obtained by intraspecific hybridization

Project objectives: In Italy the assortment of walnut valuable cultivars is very limited although rich germplasm resources are present and are still to be evaluated.

In order to give varietal addresses for new plantations, a programme was started to evaluate the performance of Italian and foreign cultivars and to create new hybrid cultivars. The aim of this research was to find out cultivars with medium to late leafing period, high yield potential, good nut quality.

Project summary and results: The most common Italian and foreign cultivars (especially American and French) were trained in a collection field in Piemonte, northern Italy, and the main vegetative and productive traits were evaluated. In general the American cultivars (except Hartley, Chase D9) showed insufficient vigour, an early leafing out, a high yield potential and often a poor nut quality. The French varieties on the contrary, were very vigorous, with a high quality, but low yield.

The crossings were started in 1989 to try to obtain new selections combining medium-high vigour, lateral fruitfulness and high nut quality. Crosses were made between cvs Hartley and Chase D9 as female parents and cvs Pedro and Vina as male parents. About 100 seedlings were obtained so far. Their evaluation is in progress.

Related publications:

RADICATI L., ME G., SACERDOTE S., VALLANIA R., 1983. Prime valutazioni di cultivars di noci americane e francesi per le zone montane. Frutticoltura, 45(3-4): 19-23.

RADICATI L., VERGANO G., ZANNINI P., 1990. Vegetative and productive evaluation of 19 walnut cultivars in Piemonte (Italy). 1st Intern. Symposium on Walnut Production, Budapest (Hungary), 25-29 Sept, 1989. Acta Hort., 284: 145-155.

RADICATI L., VERGANO G., MARTINO I., 1993. Evaluation of fruit characters in different walnut cultivars. Intern. Walnut Meet., Tarragona (Spain), 21-25 Oct. 1991. Acta Hort., 311: 49-56.

Research Project

Title: Investigations on interspecific hybridizations in the Juglans genus

Project objectives: Interspecific hybrids in the Juglans genus are known to exist both in natural environments or obtained by controlled crossing.

Some of these hybrids proved to be interesting as rootstocks because they show valuable characters.

The aim of this research is to find out the compatibility or incompatibility relationships through histological examination of pollinated flowers.

Project summary and results: Starting from 1990 the following interspecific hybridisations were carried out:

J. nigra x J. regia
J. regia x J. nigra
J. regia x J. cinerea
J. regia x J. sieboldiana

After artificial pollination, female flowers were collected daily for 10 days and fixed in FAA. The observations were made either on tissue ground and stained with aniline-blue or on tissue embedded in paraffin, sectioned and stained according to Pinney and Polito (1983) and Latorse (1985).

These methods allow the observation of pollen tubes grown on stigma surface, in the style and in the ovary tissue.

The observations are in progress.

Related publications:

RADICATI L., ME G., VALLANIA R., VERGANO G., 1990. Microsporogenesis, pollen germinability and viability in walnut cultivars with different blooming times: methods and preliminary results. Adv. Hort. Sci., 4: 139-143.

VERGANO G., 1992. Sperimentazione su alcuni aspetti della biologia del polline nel genere Juglans. These of Doctorate: 60 pp.

Research Project

Title: Improving rooting and disease resistance in walnut through tissue culture techniques

Project objectives:

- Improving of in vitro rooting ability of walnut through application of physical and chemical factors.

- Improving of in vitro rooting ability through application of localised infection with Agrobacterium rhizogenes.

- Characterisation of root formation process through histological, ultrastructural and molecular analyses.

- Improving of rooting ability by regeneration from transformed somatic embryos for A. rhizogenes rolB gene.

- Improving of adventitious shoot regeneration ability and characterisation of the morphogenesis.

- Improving of diseases resistance by regeneration of adventitious shoots carrying gene sequences with reported antifungal or antibacterial activity

Project summary and results: Exogenously applied auxins combined with dark treatment have been shown to accelerate the rooting process in this species. As an alternative or complementary strategy, localised infection with the soil bacterium Agrobacterium rhizogenes Conn., which has the potential to induce root formation at the site of infection, has also been shown to stimulate rhizogenesis in recalcitrant walnut genotypes. Exogenously applied IBA accelerates and increases root formation induced by bacteria while IAA reduces the rooting performance and both auxins induce the preferential production of non-transformed roots. The rooting process was histologically, ultrastructurally and molecularly characterised.

Somatic embryos were successfully transformed with the rolB gene, cloning of the regenerant is still in progress.

A protocol for adventitious shoot regeneration was established and it is now being used for gene transferring experiments. The adventitious regeneration process was histologically and hystochemically characterised.

Related publications:

BELISARIO A., ZOINA A., PEZZA L., CABONI E., DAMIANO C., CORAZZA L. 1997. Preliminary investigations on population dynamycs of Xanthomonas campestris pv. juglandis and other Xanthomonas in English (Persian) walnut in vitro plants. 10th Congress of the Mediterranean Phytopathological Union. Montpellier - Le Corum (France). June 1-5, 1997: 359-362.

BELISARIO A., ZOINA A., PEZZA L., CABONI E., CORAZZA L., 1998. Dinamica di popolazioni di Xanthomonidi di Noce coltivato in vitro. Atti IV Giornate scientifiche S.O.I. San Remo 1-3 aprile 1998: 299-300

CABONI E., DAMIANO C., FALASCA G., LAURI P., 1995. Rooting improvement in walnut and almond in vitro through localized infection with Agrobacterium rhizogenes. Journal of Experimental and Clinical Cancer Research, 14: 149-150.

CABONI E., LAURI P. 1995 - Effetto di fattori chimici, fisici e trasformazione localizzata sulla radicazione in vitro di noce. Italus Hortus 4 (2): 49-53.

CABONI E., LAURI P., TONELLI M.G., FALASCA G. and DAMIANO C. 1996 - Root induction by Agrobacterium rhizogenes in walnut. Plant Science, 118: 203-208.

CABONI E., TONELLI M.G., LAURI P., DAMIANO C., 1995. Factors affecting Agrobacterium tumefaciens mediated transformation of somatic embryos of walnut (Juglans regia L.). Atti della riunione annuale della SBI, Gruppo differenziamento e colture di tessuti. Bertinoro (Fo), 3-5 Luglio: 30.

FALASCA G., REVERBERI M., LAURI P., CABONI E., DE STRADIS A., ALTAMURA M.M. 2000 - How Agrobacterium rhizogenes triggers de novo root formation in a recalcitrant woody plant: an integrated histological, ultrastructural and molecular analysis. The New Phytologist, 145 (1): 77-93.

MOLDOVA

Research Project

Title: Creation of the walnut (Juglans regia L.) assortment in the Republic of Moldova

Project objectives: During the last 35 years a series of studies were carried out on more than 200 valuable biotypes revealed into the local seminal populations and 25 varieties of world selection. In spite of the good environmental adaptation of five selected and homologated varieties, production potential and resistance to diseases does not correspond to requirements of nut production intensification. The creation of new promising varieties was developed both by selection of biotypes with desired characters out of local seminal populations (including more than 2,0 mln genotypes) and through breeding programs using the best donors of late leafing, lateral fruitfulness, resistance and tolerance, to diseases, high nut quality. The local varieties with excellent nut quality and high resistance to diseases were used as female parents in dialell hybridizations with Californian varieties with lateral fruitfulness.

Cyto- and histochemical investigations of reproductive system of Juglans regia L. were carried out in this program.

Project summary and results: For the first time there was created and homologated a walnut assortment for the Republic of Moldova, including 5 aborigenal varieties: Chisinau, Schinoasa, Costiujeni, Corjeuti and Calarasi. 15 valuable biotypes, discovered in seminal populations have been studied in order to determine the potential production, 16 perspective varieties are tested in the microculture (orchard A) competition. The test of nut quality of 750 hybrids, preselected in the nursery among over 1000 hybrids, obtained from diallel crosses of homologated varieties is being done in the selection orchard. Cytoembriological studies of walnut reproductive system revealed different degrees of compatibility of all dichogamous types (49 crosses), manifestation of autofertility and apomixis. Pollinators were selected for the conditions of Republic of Moldova.

Related publications:

PINTEA M.A. 1990. Cross and auto pollination of perspective varieties and selections of walnut. In: Sortoizucenia in selectia plodovih cultur, Chisinau: 4-10 (in Russian)

PINTEA M., 1998 Walnut (Juglans regia L.) reproductive system, Chisinau: 210 p. (in Romanian)

TURCAN I.P., 1979. Walnut. Chisinau, 154 p., (in Russian)

TURCAN I., PINTEA M. 1989, Cytoembriologival peculiarities of homologated and perspective walnut varieties In: Fiziologo biohimiceskie issledovania plodovih cultur, Chisinau: 47-54, (in Russian)

TURCAN I.P., MELNICIUC L.A. 1990 Short Review of English walnut varieties investigation in Moldova, Acta Horticulturae, 284: 187 - 189

TURCAN I. 1994. Creation of the walnut assortment and production technologies based on cultivar. Chisinau: 52 p. (in Romanian)

MOROCCO

Research Project

Title: Prospects in local walnut populations in the south of Morocco

Project objectives: Locating in the population and building up a germplasm collection, at the Aïn Taoujdat field station of INRA, of walnut type showing the following remarkable characters: lateral fruiting, soft shell, good pomological characteristics, resistance to bacterial disease, drought tolerance.

Project summary and results: Introduction into the field station of 8 tree types located and chosen for their pomological charateristics and their high and regular production. Two types have been selected for the following characters: high and regular production, large nut, drought tolerance (relative to other trees into the population).

Related publications:

LAGHEZALI M., AMAHRACH M., 1992. Charactérisation morphologique d'une population de noyer issue de semis. Rapport technique INRA, 1998

PORTUGAL

Research Project

Title: Behaviour of some walnut-tree (Juglans regia) varieties in Região Agrária da Beira Litoral

Project objectives: To study the behaviour of some walnut-tree varieties in order to select the most interesting variety for the region, on the basis of the following aspects: shape, vigour, production of catkins, bursting and blooming date, harvest time, yield, tolerance to walnut blight; nut quality.

Project summary and results: A collection of 10 to 15 trees of 20 walnut cultivars had been planted in 1991. Annually the following registers are made in five trees of each variety: weekly phenological evolution since bursting to harvest; yield, susceptibility to bacterial blight and nut quality. "Lara" seems to be the best variety for this region.

Related publications: Not specified