Effect of 6-benzyladenine and gibberellic acid application on productivity and fruit quality of plum cultivar ‘Čačanska Rodna’

Plum production in Serbia is mainly extensive, followed by low and unstable yields per unit of area and small fruits with poor quality. In order to improve production and increase fruit quality, the influence of 6-benzyladenine (BA) and gibberellic acid (GA3) on fruit yield, size and storability was examined. The experiment was carried out 2016‡2017 on cultivar ‘^a~anska Rodna’ grafted on the generative rootstock Prunus cerasifera Ehrh. with the Prunus spinosa L. as an interstock and vegetative rootstock ‘Wavit’. When the fruit diameter reached 10 mm in average, the following treatments were applied: 50 mg l-1 BA, 100 mg l-1 BA, 200 mg l-1 GA3 and the untreated control. Fruits were analysed at harvest, after cold-storage at 1 ± 1°C for 28 days (2016) and 20 days (2017) and after three days of shelf-life [28 + 3 (2016) and 20 + 3 (2017)].

BA treatments significantly increase yield and fruit size, while the effect of GA3 was inconsistent. The highest yield and number of fruits per tree were achieved with the 50 mg l-1 BA in both rootstocks. Yield was increased by 118% at the ‘Wavit’ rootstock and by 66% at Prunus cerasifera/Prunus spinosa rootstock, compared to the control. The exception was 2017 for the ‘Wavit’ rootstock when the highest yield was achieved in plum trees treated with 100 mg l-1 BA. The colour expressed through chromaticity (C* ‡ hroma) varied between years, rootstock and treatments. During fruit storage, the value of bioyield point decreased significantly. In 2016 storage of plum fruits reduced bioyeld point for almost 50%, while in 2017 reduction was around 30%.