Evaluation of German Plum Selections in Latvia

The aim of the study was to determine the suitability of growing plum cultivars and hybrids of German origin in Latvian conditions. In the trial the plum cultivars and hybrids were planted at the Latvia State Institute of Fruit Growing (now, Institute of Horticulture) in spring 2008. Six W. Hartmann genotypes (cultivars ‘Tipala’, ‘Tegera’ and ‘Haganta’, and hybrids H-5102, H-3753, and H-3690) from Hohenheim University were included in the study. Prunus cerasifera was used as rootstock. The parameters evaluated were: beginning of flowering, ripening time, average yield (kg per tree), cumulative yield (kg), and average fruit weight from 2012 to 2016, and content of soluble solids from 2014 to 2016. In addition, self-fertility was evaluated in 2015 and 2016 for three cultivars and one hybrid. The winter of 2010/2011 was unfavourable, as plum orchards and most plum cultivars in Latvia suffered winter damage, but cultivars and hybrids in the trial were without damages. Significant damages were not observed in further years. Average flowering time in the four-year period for all cultivars and hybrids was the 1ˢᵗ or 2ⁿᵈ decade of May, harvest time was from the 1ˢᵗ decade of August to the 3ʳᵈ decade of September. The earliest was hybrid H-3690, and the latest was cv.’Haganta’. The most productive was hybrid H-3690, which gave 42 kg in the 3ʳᵈ year of yield and had the most rapid rise in yields. ‘Haganta’ had the biggest fruits (50 to 60 g) and highest content of soluble solids (17-18 Brix%). Self-fertility level was 40% for ‘Tegera’, 17.4% for ‘Haganta’, 14.5% for H-3690 and 0% for ‘Tipala’. Evaluation of all analysed parameters showed that ‘Tegera’ could be recommended for Latvian growers thanks to good winter hardiness in the research period. ‘Haganta’ is recommended only for warmer regions in Latvia. Hybrid H-3690 will potentially be useful for Latvian growers.