No abstract

The study was performed at the Experimental Station of Agriculture - Khan Krum in the period 2018-2019. The experimental plantation was established in 2001, the early Bigareau Burlat, middle early Bing and the late Germersdorfer and Van were tested. The planting material was produced on a mahaleb rootstock. The distance of planting was 6 meters interrow spacing and 5 meters intrarow spacing. The experiment was based on three replications each of them reported on a separate tree. When analyzing the frost percentage of flowers, 400 blossoms were taken from three levels of the crown of each tree, the same number of fruits were taken to determine the cracking percentage. Percentage of damaged blossoms, yield kg/ha and percentage of fruit cracking as a result of fallen rains during harvest were established. The purpose of the study is to investigate the influence of abiotic factors on the yield and quality of four sweet cherry cultivars. In this regard, the frost percentage in the range of values was 67,3 - 100%. Bigareau Burlat yield was not obtained, and it was relatively low from Germersdorf and Bing (20,1 - 24,6 kg/ha) at Van 84,6 kg/ha. The number of cracked fruits due to fallen rains during harvest was relatively high in Van and Bing (39,8 - 47,4%), while in the Germersdorf cultivar it was lower - 21,2%.

Abstract. During the period 2015-2017, scientific expeditions were conducted in the region of the town Shumen, located in the north-eastern part of Bulgaria, mainly around the village Madara where the concentration of natural forms derived from seedlings is the greatest. The purpose is to discover and research old local forms of the so called “vineyard peach” and to preserve them for possible future inclusion in breeding programmes to create new cultivars using more extended genepool. As a result, three forms of “vineyard peach” were selected from the local populations. The fruits of the three local forms are small and with primitive taste qualities but fit for human consumption. Two of the forms have white fruit flesh and one is with green. Two of the peach forms have vigorous growth, but one of the forms with white fruit flesh is of weak vigour. The three forms are spontaneous natural products obtained through long-term seed propagation. The trees are old but vital and without visual damage by diseases and pests, regularly bear fruits and have good annual growth despite competition from weeds, bushes and trees.

The study was conducted during the period 2017 – 2018 at the Agricultural Experimental Station – Khan Krum, Shumen region. The experimental orchard was established in the spring of 2011. The following nectarine cultivars were studied: Fantasia, Golden Grand, Morsiani 51, Cassiopeia and Fairlane grafted on a seedling rootstock (Elberta) and clonal GF 677, as well as the frost – resistant dessert-type cultivar Redhaven. In the period 2017 – 2018, negative temperatures were reported, at the end of March and at the beginning of April (-3.6°C and -5.0 °C respectively)which coincided with the full blooming phenological phase; as a result of which the blossoms froze (76 – 100%). A relatively low percentage of frozen blossoms was observed in cultivars grafted on rootstock GF 677. In 2017, the blossom damage was relatively low and yields were obtained, unlike in 2018. Negative spring temperatures had a negative impact on productivity if blossom damage percentage exceeded 80%.

Abstract:The aim of the present study was to establish the growth characteristics of the red-leaf peach hybrid No. 9-205, grown in a nursery, targeting its submission in future for recognition as a new vegetative rootstock for peach and nectarine cultivars. The traditional seedling rootstock 'Elberta' and the vegetative one GF-677 were included in the study. Hybrid No. 9-205 was selected from a population obtained at the FruitGrowing Institute in Plovdiv by open pollination of Rutgers Red Leaf seedling rootstock for peach, used in the past. It is characterized by high drought resistance and good resistance to diseases and pests. It is easily propagated under in vitro conditions and shows weaker growth compared to GF-677 rootstock. 18 cultivar/rootstock combinations were studied, including two cultivars of each peach type: for fresh consumption, for processing and of the nectarine type. 'Laskava' cultivar for fresh consumption, the processing cultivar 'Spasena' and the cultivar 'Gergana', which is of the nectarine type, are newly established in result of the implementation of the breeding programme at the Fruit-Growing Institute -Plovdiv. They were officially recognized in the period 2009-2012. The percentage of survival and of grafted bud shooting is high enough and meets the requirements of the production practices in nurseries. The planting material of the vegetative rootstock No. 9-205 is uniform in plant height and stem width and it fully complies with the quality standards.