Development of models and assessment of the world walnut variety fund by fruit quality

Walnut (Juglans regia L.) is a particularly significant plant for humans in terms of its useful properties and in the Russian Federation it can be attributed to the most valuable introducers for forestry and horticulture. It is grown in many countries of the world and the area of its cultivation is constantly expanding. Breeding species for food purposes requires a selection assessment of the quality of its fruits. For this, at different times, appropriate methods were developed and the existing gene pool of the culture was assessed. By now, new varieties and forms have been bred and brought, which also need to be evaluated for rational use for scientific and practical purposes. The descriptions of varieties and forms of walnut often contain insufficient information about all selected traits, which requires the development of new models to assess the variety fund using incomplete data. The purpose of the research is to develop the missing models of selection evaluation using incomplete data and evaluate the world walnut variety fund in terms of fruit quality, to identify varieties and forms of the highest quality category. The well-known methodology and new models have been used for the evaluation. When developing evaluation models for incomplete data, a database of 50 varieties evaluated for all indicators has been used. Using the method of excluding individual indicators, the corresponding multiple regression models have been calculated on its basis, taking into account a different combination of features. The licensed programs Stadia 8.0, Microsoft Excel have been used in the research. The proposed models provide an estimate with an average error of ± 0.48 – 3.72 points at R2 = 0.63 – 0.99. A promising walnut gene pool from 23 countries has been assessed, 69 representatives with fruits of the breeding category of the highest quality identified, and a list of them compiled. Of the 512 ancestors, 19.73% had the selection category of fruits of the highest quality, 62.88% of high-quality fruits, 16.80% of ordinary fruits, and 0.59% of varieties and forms of low-quality fruits.

1. The program of the North Caucasus Center for the selection of fruit, berry, flower and ornamental crops and grapes for the period up to 2030. Krasnodar, 2013. (In Russ.)

2. Sukhorukikh Yu.I. Selected works. V. 2. Walnut. Maikop: Quality, 2008. (In Russ.)

3. Ertürk U., Şisman T., Yerlikaya C. [et al.] Chemical composition and nutritive value of selected walnuts (Juglans Regia L.) from Turkey. Acta Hortic. 2014; 1050:231–234.

4. Ozcan A., Sutyemez M., Attar S.H. [et al.] Fatty acid composition, phenolic compound content and antioxidant activity of unique walnut genotypes with red seed coa. Journal of Food and Nutrition Research. 2020; 59(4): 352–360.

5. Ivanov A.L., Kulik K.N. Agroforestry. 5th ed. revised and add. Volgograd: VNIALMI, 2006. (In Russ.)

6. Panfilov A.V. [et al.] Features of growing walnuts in the conditions of the Right-bank zone of the Saratov region. Vavilov Readings – 2020. Saratov; 2020: 198-200. (In Russ.)

7. Ryadnova T.S., Slavsky V.A. Selection of walnut in the Belgorod region. Actual directions of scientific research of the XXI century: theory and practice. 2020; 3: 403-408. (In Russ.)

8. Starshinov D.S., Kornilova V.A. Study of the growing conditions of zoned walnuts in the city of Samara. Samara; 2020: 146–147. (In Russ.)

9. Sukhorukikh Yu.I. Recommendations for the assessment, description and zoning of the walnut. Maikop: MSTU, 1997. (In Russ.)

10. Ertürk U., Mert C., Soylu A. [et al.] Evaluation of some domestic and foreign walnut cultivars in the conditions of Bursa, Turkey. Acta Hortic. 1050, 123–129.

11. Iannamico L. Technologic problems to face when establishing walnut in new cold areas: the experience in the southern hemisphere. Actahortic. 2014; 1050: 395–398.

12. Leslie C.A., McGranahan G.H. The California walnut improvement program: scion breeding and rootstock development. Actahortic. 2014; 1050:81–88.

13. Sluite I.R.K., McKenzie L., Mitchell J.R. Walnut rootstock selection for calcareous soils in Southeastern Australia and the potential for expanding the walnut industry in the region. Acta Hortic. 2014; 1050:105–111.

14. https://orehovod.com/articles/55-rossiiskie-sorta-greckogo-oreha.html 2022 [updated 15 July 2015; cited 12 February 2022]. Available: https://orehovod.com.

15. https://kubansad.ru/content/sorta/orehoplodnye 2021 [updated 2021; cited 17 February 2022]. Available: https://kubansad.ru

16. https://sultansad.by/product/sazhency-greckogo-oreha-samohvalovicheskij-2 2022 [updated 2022; cited 19 February 2022]. Available: https://sultansad.by

17. https://krim-pitomnik.ru/oreh-greckiy-oreh-ot-kiktenko-n-f/702-kostyuzhanskiy [updated 2022; cited 21 February 2022]. Available: https://krim-pitomnik.ru

18. http://rasteniy10.ru/internet-magazin/product/oreh-greckij-vityaz-juglans-regia-l-cultivarhero-orehovye-juglandaceae-lindl [updated 2022; cited 1 March 2022]. Available: http://rasteniy10.ru

19. https://vivaizanzi.it/en/product-category/walnut/ 2022 [updated 2017; cited 9 March 2022]. Available: https://vivaizanzi.it

20. www.pepiniere-payre.fr 2022 [updated 2018; cited 13 March 2022]. Available: www. pepiniere-payre.fr

21. https://agrocorp.com.ua/ 2022 [updated 02/13/2021; cited 13 March 2022]. Available: https:// agrocorp.com.ua

22. https://www.coulie.com/catalogue-noyer/ 2020 [updated 2020; cited 15 March 2022]. Available: https://www.coulie.com

23. Sukhorukikh Yu.I., Lugovskoy A.P., Biganova S.G. The program and methodology of walnut breeding. Maykop: Kachestvo, 2007. (In Russ.)

24. Sukhorukikh Yu.I., Biganova S.G. Optimization of the evaluation of the quality of walnut fruits. Maykop: Kachestvo, 2003. (In Russ.)

25. Schepotiev F.L., Richter A.A., Pavlenko F.A. Walnut forest and horticultural crops. Moscow: Agropromizdat; 1985. (In Russ.)