S.I. Gandev
Fruit-Growing Institute, 4004 Plovdiv, Bulgaria

SUMMARY Introduction – The high protein and oil content of walnut kernels makes them essential for human nutrition. Therefore, the walnut is classified as a strategic species included in the FAO list of priority plants. The aim of the present experiment was to study and compare the agrobiological characteristics of some introduced and local walnut cultivars under the climatic conditions of South Bulgaria, as well as to define the cultivars that are perspective for growing in our country. Materials and methods – The study was carried out on the Bulgarian walnut cultivars Sheynovo and Izvor 10, the US cvs. Serr and Hartley, the French cvs. Lara and Fernor and the Hungarian cv. Tiszacsecsi 83, grown under the ecological conditions of Plovdiv region, Central South Bulgaria. Results and discussion – The cultivars Fernor and Izvor 10 bore fruits on 80% of the lateral buds along the fruiting shoots. They are followed by 'Lara' (45%), 'Serr' (35%), 'Sheynovo' (25%), 'Tiszacsecsi 83' (15%) and 'Hartley' (10%). The mean fruit weight ranged from 10.63 g for 'Tiszacsecsi 83' to 13.62 g for 'Sheynovo'. The cumulative yield ha-1 for the period 2009–2014 was 17,605 kg ha-1 for 'Serr', 16,080 kg ha-1 for 'Fernor' and 15,301 kg ha-1 for 'Izvor 10', followed by 'Lara' and 'Hartley' (13,717 and 13,280 kg ha-1, resp.). The yields were low for 'Sheynovo' and for 'Tiszacsecsi 83' (9,211 and 4,917 kg ha-1, respectively). Conclusion – The Bulgarian 'Izvor 10' and the French 'Fernor' and 'Lara' can be recommended for commercial growing in South Bulgaria. Résumé Comportement de certains cultivars de noix locaux et étrangers dans les conditions climatiques du Sud de la Bulgarie. Introduction – La haute teneur en huile et en protéine de la noix du noyer la rend essentielle en nutrition humaine. Par conséquent, le noyer est classé comme espèce stratégique inscrite dans la liste FAO des plantes prioritaires. Le but de la présente étude est de comparer les caractéristiques agrobiologiques de certains cultivars de noyers locaux et introduits dans les conditions climatiques du Sud de la Bulgarie, ainsi que de définir les cultivars prometteurs pour la culture dans ce pays. Matériel et méthodes – L'étude a été réalisée avec les cultivars de noyers bulgares Sheynovo et Izvor 10, les cvs. américains Serr et Hartley, les cvs. français Lara et Fernor et le cv. hongrois Tiszacsecsi 83, tous cultivés dans les conditions écologiques de la région de Plovdiv, au centre-Sud de la Bulgarie. Résultats et discussion – Les cultivars Fernor et Izvor 10 portent des fruits sur 80% des bourgeons latéraux le long des pousses fructifères. Ils sont suivis par 'Lara' (45%), 'Serr' (35%), 'Sheynovo' (25%), 'Tiszacsecsi 83' (15%) et 'Hartley' (10%). Le poids moyen du fruit varie de 10,63 g pour 'Tiszacsecsi 83' à 13,62 g pour 'Sheynovo'. Le rendement cumulatif ha-1 pour la période 2009–2014 était de 17.605 kg ha-1 pour 'Serr', 16.080 kg ha-1 pour 'Fernor' et 15.301 kg ha-1 pour 'Izvor 10', suivi de 'Lara' et 'Hartley' (13.717 et 13.280 kg ha-1, respectivement). Les rendements étaient faibles pour 'Sheynovo' et pour 'Tiszacsecsi 83' (9.211 et 4.917 kg ha-1, respectivement). Conclusion – Le cv. bulgare Izvor 10 et les cvs. français Fernor et Lara peuvent être recommandés en culture commerciale dans le Sud de la Bulgarie. Keywords Juglans regia, fruit morphological characteristics, fruit tree production Mots clés Juglans regia, caractères morphologiques du fruit, production fruitière, qualité de la noix

Significance of this study What is already known on this subject? The agrobiological characteristics of walnut cultivars are different when they are grown under different climatic conditions. What are the new findings? One local and two introduced walnut cultivars were found suitable for the growing conditions of South Bulgaria. What is the expected impact on horticulture? Increasing fruit yield and quality of walnut is expected in the Republic of Bulgaria from new commercial walnut plantations made of these cultivars.

E-mail: s.gandev@abv.bg  

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Received: 15 July 2016 | Accepted: 28 September 2016 | Published: 27 January 2017 | Available online: 27 January 2017