Advance of assortment of plums in the South of Russia

The history of forming of the majority of stone-fruit cultures are closely linked with the North Caucasus. Its widespread intra-specific diversity will allow creating new stone fruit plants with improved genotype.

On the basis of the Crimean experimental selection station and the North-Caucasus zonal scientific research Institute of horticulture and viticulture a collection of stone-fruit cultures is being preserved, maintained, and represented by a significant genetic and ecological and geographical diversity of species, varieties and hybrid forms. The gene pool of the station counts more than 5000, that of the Institute - 285 samples.

Directed use of genetic collection gives a great possibility to breed a new generation of cultivars and allocate varieties for both domestic and foreign selection, to have basic economic signs, to form a modern regional assortment of stone-fruit cultures. Increasing abiotic and biotic environment stresses indicate the need for a strategic transition to adaptive gardening, focused on the development of modern directions in the field of fundamental and applied research of high priority, new approaches to private breeding of stone-fruit cultures [2, 3, 4]. Fundamental breeding is an improvement of methods and techniques, identifying patterns of the inheritance of traits, selection of donors and sources of these characteristics, methods of synthesis of new original forms with high potential for resistance to complex stress factors combined with high productivity and quality of fruits. Practical breeding is an effective use of accelerated obtaining fundamentally new cultivars using DNA technologies and their implementation in industrial production to breed the most sustainable and productive agricultural lands of stone fruit trees, including plum in the South of Russia.

Materials and methods

Investigated varieties of plums, created in the Crimean experimental breeding station and NCSRIHV. Breeding work, cultivar trials conducted using relevant programs [5, 6].

Results

Plums have a special role among stone-fruit cultures. It is cultivated in all of fruit areas in the southern region, due to the adaptability and flexibility, high potential productivity and versatility of use of the fruit. However, despite this, plums, as well as less adaptive stone fruit, require improving the assortment and breeding of comprehensive sustainable and productive cultivars. One of the ways is to breed local cultivars.

High-priority methods to select plums (Prunus domestica L.) remain crossing on the hardiness and resistance to frost, as the repetitive extreme temperature (below minus 28 degrees C) in a dormant period lead to freezing or loss of its generative and vegetative organs, as it was in the winter of 2005/2006 biennium, when the temperature fell to - 34 °С in Kuban and to - 38 °С in Steppe zones of Krasnodar region. As a result, most cultivars of both domestic and foreign selection (Kabardinskaya rannaya, Predgornaya, Melitopolskaya, Stenley, Chachakskaya uluchshennaya, Turchanka and others) had no fruits.

Positive results frost and winter hardiness cultivars showed cultivars of local selection, which shown strong frost resistance and high reducing capacity. So, frost-resistant are new cultivars of plum bred by Crimean experimental breeding station, such as Debjut, Golubaja mechta, and breed by NCSRIHV - Podruga i Krasotka. They shown high resistance to extreme winter temperatures and a higher reducing ability of the various organs after exposure to frost, which reached to 4 points (see the Table below).

Table. Assessment of the most important economically useful signs varieties of plums

Defining resistance of new plum cultivars to biotic factors has revealed that they are less affected by Coryneum blight and blossom wilt, compared with others. So, in the period of study in the Krasnodar territory lesion of cultivars by Coryneum blight varied from 1 to 3 points, and in the years of strong spread of disease (2006 and 2008) reached 3,5...4,0 points, depending on the type and year.

Lesion within three points during the study period was observed in grades Krasnodarskaja, and Prikubanskaya, Osennyaya, Gertsog had that at the level of two points. The plum varieties breeding Crimean experimental breeding station time of Coryneum blight not exceed 1.5 points (Osennij suvenir).

Monitoring showed that the cultivars of plums are less affected by blossom wilt (not more than two points) than by Coryneum blight.

Comprehensive assessment of plum cultivars of local selection bred from targeted crosses in the conditions of the Foothill and Kuban areas of Krasnodar region, showed a sufficiently resistance of the following varietes to Coryneum blight and blossom wilt: Ballada, Debut, Lider, Golubaya mechta bred by Crimean experimental breeding station, Podruga, Milena and Krasotka – bred by NCSRIHV, lesion of which during epiphytotic years did not exceed 0,5...1,0 points.

As an element of productivity of stone fruit crops is their early appearance of fruit, we have identified the most early appeared cultivars in a new group that come into fruition on the third or fourth year after planting in the garden: Krasnodarskaya, Gertsog and Krasotka bred by NCSRIHV; Ballada, Debut, Golubaya mechta bred by Crimean experimental breeding station.

Cultivars of plums, including new local ones, fruit almost annually and form a high yield (20...25 t/hectare and more), depending on the intensity of cultivation technology. Exceptions are the years of thermal stresses in a dormant period (2006) and flowering (2009) as well as in epiphytotic periods, when the main part of the plum cultivars had no fruits.

Efficiency analysis of new plum cultivars confirmed that the yield determined their product potential, as well as the degree of resistance to stress factors of various types.

The period of 2005-2010 was changeable, when almost every year turned out to be extreme for the southern stone fruit crops. However, at these terms the assessment of the productivity of plum cultivars has shown their high productivity and the potential of a sustainable harvest in extreme conditions.

New cultivars bred by NCSRIHV gave, yield, varied from 15 to 18 t/ha: Podruga (17,0), .Prikubanskaya (18,0), krasnodarskaya (17,0); cultivars bred by Crimean experimental breeding station varied from 18 to 25 t/ha: Autumn souvenir (18,0), Ballads (22,0), Blue dream (25,0). They are also characterized by high quality of the fruit. Large-fruited cultivars with the weight of 45...50 g are bred by Crimean experimental breeding station, these are Osenniy suvenir (60,0), Lider (50,0), Ballada (45,0); bred by NCSRIHV: Osennjaya (45,0 g), Podruga (45,0 g), Gercog (50,0 g). High-taste cultivars (taste 4,6...4.8) are Ballada, Osenniy suvenir, Golubaya mechta (Crimean experimental breeding station); Osennaya Millena, Podruga, Gertsog and Krasotka (NCSRIHV).

Released assortment is especially lack of high-quality and productive plum cultivars of early and late ripening of domestic selection. Breeding these cultivars helps to improve the possibilities of realization of fruits during periods when they are most in demand. New cultivars of the highest interest are: Lider and Debut, bred by Crimean BSS, maturing before the main early cultivars of the Kabardinskaya rannaya exceed the yield of standard early cultivar Kubanskaya rannaya. Late cultivars are cultivars bred by Crimean Breeding Selection: Osenniy suvenir and Golubaya mechta, ripening in time, close to the late introduced Stenley cultivar.

Conclusions

Thus, in the conditions of southern gardening group of new plum cultivars are bred by breeders of our country: Debut, Lider, Golubaya mechta (CBSS) and Gertsog, Podruga and Krasotka (NCSRIHV), characterized by high winter hardiness, resistance to Coryneum blight and blossom wilt (1... 2 points), high on years of potential productivity (18...25 t/ha) and quality of fruits (4,5...4.8 points).

In recent years, the results of the breeding work in the State testing gave three plum cultivars bred by CBSS (Debut, Lider, Golubaya mechta); four bred by NCSRIHV {Krasnodarskaya, Podruga, Gertsog, Mechta}. Register of breeding achievements of the Russian Federation included two varieties breeding of CBSS — Ballada and Osenniy suvenir; Prikubanskaya cultivar bred by NCSRIHV, which serve as a good Supplement to region assortment of plums in Krasnodar region [1].