Current Trends in Natural Sciences Vol. 10, Issue 19, pp. 387-393, 2021 https://doi.org/10.47068/ctns.2021.v10i19.051 Current Trends in Natural Sciences (on-line) Current Trends in Natural Sciences (CD-Rom) ISSN: 2284-953X ISSN: 2284-9521 ISSN-L: 2284-9521 ISSN-L: 2284-9521 http://www.natsci.upit.ro *Corresponding author, E-mail address: septarleinar71@gmail.com 387 BIOMETRIC CHARACTERISTICS OF 'ORIZONT' APRICOT CULTIVAR UNDER STRESS HYDRIC CONDITIONS Leinar Septar 1,* , Cristina Moale 1 , Larisa Tilinca 1 , Ioan Stoli 1 1 Research Station for Fruit Growing (RSFG) Constanta, 25 Pepinierei Street, Valu lui Traian, Constanta, Romania Abstract Irrigation is a major activity in arid and semi-arid regions for many crops, including orchards. The deficit irrigation is an alternative in the context of global warming. The crop studied was apricot, 'Orizont' cultivar, 16 years old, grafted on the 'Constanta 14' rootstock. The planting distance was 4 m between the rows and 5 m between trees in the row. Fruit size and weight are important qualities and yield traits in apricot (Prunus armeniaca L.), but the factors that influence fruit size and weight remain to be explored. The fruit biometrical characteristics was influenced by the irrigation regime, with the irrigated treatment with 100% AHI (T1) showing significantly (P <5%) higher differences versus T2 and T3. As with fruit biometrical characteristics, the fruit weight determined on the fruits of the studied treatments had the same trend. In this study, we investigated the impact of stress hydric on fruit size and weight at 'Orizont' apricot cultivar in 2019-2020 period. Keywords: climatic conditions, longitudinal diameter of fruit, Prunus armeniaca L, weight of fruit. 1. INTRODUCTION At present and more so in the future, irrigated agriculture will take place under water scarcity. Insufficient water supply for irrigation will be the norm rather than the exception, and irrigation management will shift from emphasizing production per unit area towards maximizing the production per unit of water consumed, the water productivity (Fereres and Soriano, 2007). To cope with scarce supplies, deficit irrigation, defined as the application of water below full crop-water requirements (evapotranspiration), is an important tool to achieve the goal of reducing irrigation water use (Fereres and Soriano, 2007). The concept of regulated deficit irrigation (RDI) was first proposed by Chalmers et al. (1981) and Mitchell and Chalmers (1982) to control vegetative growth in peach orchards, and they found that savings in irrigation water could be realized without reducing yield. Nevertheless, experiments with RDI have been successful in many fruit tree and nut species such as apricot (Ruiz-Sánchez et al., 2000), almond (Goldhamer et al., 2000), pistachio (Goldhamer and Beede, 2004). If deficit irrigation (DI) is used, monitoring the soil or plant water status is even more critical for minimizing risk, given the uncertainties in determining the exact water requirements. In Romania, apricot is highly appreciated, but its favorability area is relatively restricted from the climate view point. It finds proper climate conditions in Dobrogea region, Romania, (winter temperatures not too low), more favorable than in other regions of the country.