Walnut (Juglans regia L.) is one of the most important fruit species in the world because it is rich in nutrients and elements, and is a high-quality wood. There is an increasing interest by consumers in eating walnuts, especially in Middle Eastern countries. Walnuts have favorable amounts of fatty acids, nutrients, and minerals. Anatolia is one of the originating centers of many fruit species, including the walnut (Juglans regia L.), which is a result, in part, of its unique geographic location, which brings about different types of climatic and edaphic conditions. Encountering a walnut tree in almost any part of Anatolia is a common experience, and many Anatolians are interested in walnuts as a local nut crop. The existing genetic diversity of walnuts in this area is very important for walnut breeders. To date, numerous walnut breeding studies have been carried out throughout the world (Akça et al., 2016; Germain, 1990, 1995; Vahdati et al., 2019). The general objectives of walnut breeding programs in many countries are to provide late-leafing cultivars with a high yield and a resistance to biotic and abiotic stresses. However, there has been a limited number of studies on the cluster-bearing habit in walnuts (Germain et al., 1997; Rezaee et al., 2006; Sutyemez, 1998; Vahdati et al., 2014). For this reason, our study evaluates the tree characteristics of the walnut cultivar Maraş 12, which has been registered in Turkey. ‘Maraş 12’ is a new walnut cultivar with a high number of nuts per cluster. This cultivar was released in 2016 by Kahramanmaraş Sütçü İmam University, Faculty of Agriculture, Kahramanmaraş province, Turkey (Anonymous, 2019). This walnut cultivar has a high estimated yield, with a nut weight of 9 to 12 g and a kernel weight of 5 to 7 g.
Origin
‘Maraş 12’ was selected among a diverse range of genotypes in the Kahramanmaraş province of Turkey in 1994 (Sutyemez, 1998, 2016; Sütyemez et al., 2018). To compare the performance of ‘Maraş 12’ with ‘Chandler’, 10 replicates (i.e., scions) of both cultivars were grafted onto walnut rootstocks of the same age in 2001. The walnut breeding program was carried out at the University of Kahramanmaraş Sütçü İmam, Nut Application and Research Center (SEKAMER). The objective of this breeding program, which took from 1994 to 2018, was to obtain promising cultivars characterized by important tree habits, nut traits, and resistance to some diseases.
Description
The aim of our research was to provide information on the new walnut cultivar Maraş 12. Here we report phenological and pomological traits according to the walnut descriptor and International Union for the Protection of New Varieties of Plants (UPOV) (Anonymous, 1994, 2015). Data were collected for 4 years of observation (2015–18) on 10 ‘Maraş 12’ and 10 ‘Chandler’ trees.
Phenological evaluation.
‘Maraş 12’ is an early-season cultivar; its leafing date is about 3 weeks earlier than ‘Chandler’. In general evaluations, ‘Maraş 12’ tends to initiate the growth of leaves before other established cultivars in the season. In comparison with ‘Chandler’, ‘Maraş 12’ shows an earlier blooming of its male and female flowers. Both types of flowers bloom simultaneously (which indicates homogamy). Nonetheless, the aim of this article is to emphasize the cluster-bearing habit of ‘Maraş 12’ as its most important trait (Fig. 1). The clusters of the female flowers in ‘Maraş 12’ can be comprised of up to 21 flowers, leading to a high estimated yield.
A tree view of ‘Maraş 12’ at full-yield stage.
Citation: HortScience horts 54, 8; 10.21273/HORTSCI14226-19
A tree view of ‘Maraş 12’ at full-yield stage.
Citation: HortScience horts 54, 8; 10.21273/HORTSCI14226-19
A tree view of ‘Maraş 12’ at full-yield stage.
Citation: HortScience horts 54, 8; 10.21273/HORTSCI14226-19
The abundance of female flowers in ‘Maraş 12’ is heavy, and catkin abundance is intermediate. About 80% to 85% of the lateral buds turn out to be fruitful. ‘Maraş 12’ is generally harvested toward the second week of September in the Kahramanmaraş region. ‘Maraş 12’ fruits mature about 1 month earlier than ‘Chandler’. Its defoliation date is generally about 3 weeks earlier than that of ‘Chandler’ (Table 1).
Average phenological and pomological traits of ‘Maraş 12’ compared with the standard ‘Chandler’ cultivar during 4 consecutive years.
Pomological traits.
The shape of the nuts is medium-size ovate. The shell of most nuts is weak, very smooth in texture, and very light in color. The kernel is very easy to remove. The kernels of ‘Maraş 12’ are light brown (Fig. 2). By conducting measurements on 800 nuts during a period of 4 years, it was observed that each nut can weigh 9 to 12 g, each kernel can weigh 5 to 7 g, and kernel percentage is 55% to 65% (Table 1).
A view of ‘Maraş 12’ nuts from different angles.
Citation: HortScience horts 54, 8; 10.21273/HORTSCI14226-19
A view of ‘Maraş 12’ nuts from different angles.
Citation: HortScience horts 54, 8; 10.21273/HORTSCI14226-19
A view of ‘Maraş 12’ nuts from different angles.
Citation: HortScience horts 54, 8; 10.21273/HORTSCI14226-19
‘Maraş 12’ was registered and patented as a new walnut cultivar within the framework of walnut breeding regulations at the University of Kahramanmaraş, Sütçü İmam, Turkey. This cultivar is important because the fruitfulness of its cluster-bearing habit that, for this particular type, is comparable to other walnut cultivars. ‘Maraş 12’ can also be appreciated for its high fruit yield, which results in part from the existence of more than 21 flowers per cluster; good fruit quality; and early harvest and defoliation dates. These qualities are measurably distinct from other commercially grown cultivars in the world. ‘Maraş 12’ is recommended for regions where early spring frost is not a high risk of damage to flowers and fruit set.
Availability
Scions of ‘Maraş 12’ are available to walnut growers for grafting and, by appointment, can be collected from the Faculty of Agriculture, Kahramanmaraş Sütçü İmam University, Kahramanmaraş, Turkey.
Literature Cited
Akça, Y., Sütyemez, M., Yilmaz, S. & Karadag, H. 2016 The new walnut variety breeding program in Turkey, p. 461–466. In: Book of Proceedings, VII International Scientific Agriculture Symposium “Agrosym 2016”. Jahorina, Bosnia and Herzegovina
Anonymous 1994 Walnut descriptors for walnut (Juglans spp.). International Plant Genetic Resources Institute, Rome, Italy
Anonymous 2015. Walnut guidelines for the conduct of tests for distinctness, uniformity and stability. International Union for the Protection of New Varieties of Plants, Geneva, Switzerland.
Anonymous 2019 Meyve ve Asma Çeşit Listesi (Fruit Vine), Tescilli çeşitler listesi (Registered varieties). Republic of Turkey Ministry of Agriculture and Forestry Variety Registration and Seed Certification Center. 7 May 2019. <https://www.tarimorman.gov.tr/BUGEM/TTSM/Sayfalar/Detay.aspx?SayfaId=87>
Germain, E. 1990 Inheritance of late leafing and lateral bud fruitfulness in walnut (Juglans regia L.), phenotypic correlations among some traits of the trees Acta Hort. 284 125 134
Germain, E. 1995 Genetic improvement of the Persian walnut (Juglans regia L.), p. 21–32. In: III International Walnut Congress 442
Germain, E., Delort, F. & Kanivets, V. 1997 Precocious maturing walnut populations originating from central Asia: Their behavior in France Acta Hort. 442 83 90
Rezaee, R., Grigoorian, W., Vahdati, K. & Valizadeh, M. 2006 Evaluation of morphological traits associated with the vigor of Persian walnut seedlings Iranian J. Hort. Sci. Technol. 7 3 1437 1438
Sutyemez, M. 1998 Researches on walnut selection in Kahramanmaraş region and fertilization biology of selected genotypes. Cukurova University, Institute of Science, PhD Diss
Sütyemez, M. 2016 New walnut cultivars: Maraş 18, Sutyemez 1, and Kaman 1 HortScience 51 1301 1303
Sütyemez, M., Özcan, A. & Bükücü, Ş.B. 2018 Walnut cultivars through cross-breeding: ‘Diriliş’ and ‘15 Temmuz’ J. Amer. Pomol. Soc. 72 3 1437 1438
Vahdati, K., Arab, M.M., Sarikhani Khorami, S., Sadat Hosseini, M., Leslie, C.A. & Brown, P.J. 2019 Advances in walnut (Juglans regia L.) breeding strategies. In: J.M. Al-Khayri, S.M. Jain, and D.V. Johnson (eds.). Advances in plant breeding strategies, Vol 4. Nut 139 and beverage crops. Springer, Switzerland
Vahdati, K., Hassani, D. & Rezaee, R. 2014 Behavior of some early mature and dwarf Persian walnut trees in Iran Acta Hort. 1050 189 196
