Growth and yield performance of late-season plum cultivars in the Belgrade area

Abstract

Characteristics of growth and cropping (trunk cross-sectional area, yield per tree, yield efficiency, biennial bearing index, and fruit weight) were studied in 25 late-season plum cultivars in the Belgrade area during the eight-year period (2012-2019). The cultivar 'Stanley' was used as a control for comparison. The period of study was divided into initial bearing (age of trees: four and five years) and full bearing (age of trees: between six and eleven years). Significant differences in yield among cultivars were found in both initial and full bearing periods. The average yield per tree in the period of initial bearing ranged from 1.6 kg in 'Pozna Plava' to 10.9 kg in 'Topper', and from 12.3 kg in 'Pozna Plava' to 26.1 kg in 'Mildora' in the period of full bearing. Compared with the control cultivar, significantly lower yields in the full bearing period were obtained in eight cultivars, while higher vigour, expressed as trunk cross-sectional area (TCSA), was found in ten cultivars. Cumulative yield efficiency varied between 0.46 kg/cm2 in 'Požegača' and 1.90 kg/cm2 in 'Topper'. Biennial bearing index was the lowest (0.06) in 'Nada', and the highest (0.90) in 'Tophit'. Fruit weight ranged from 17.9 g in 'Požegača' to 57.0 g in 'Empress'. Compared with the control, fruit weight was significantly higher in seven cultivars, and significantly lower in nine cultivars. On the basis of high yields and large fruit size, the cultivars 'Bluefre', 'Empress', 'Jojo', 'Nada', 'President' and 'Tophit' can be recommended for growing in the Belgrade region.

Karakteristike rasta i rodnosti (površina poprečnog preseka debla, prinos po stablu, koeficijent rodnosti, indeks alternativne rodnosti i masa ploda) proučavane su kod 25 sorti šljive poznog vremena zrenja na području Beograda u periodu od osam godina (2012-2019). Kao standard za poređenje je uzeta sorta Stenli. Period ispitivanja je podeljen na početnu rodnost (starost stabala četiri i pet godina) i punu rodnost (starost stabala 6-11 godina). Utvrđene su značajne razlike u prinosu između proučavanih sorti, kako u periodu početne, tako i u periodu pune rodnosti. Prosečan prinos po stablu u periodu početne rodnosti je varirao od 1,6 kg (Pozna plava) do 10,9 kg po stablu (Toper), a u periodu pune rodnosti od 12,3 kg (Pozna plava) do 26,1 kg (Mildora). U poređenju sa standard sortom, statistički značajno niži prinos u periodu pune rodnosti imalo je osam sorti, dok je veću bujnost, izraženu preko površine poprečnog preseka debla, imalo deset sorti. Masa ploda je bila u rasponu od 17,9 g (Požegača) do 57,0 g (Empres). U odnosu na kontrolu, sedam sorti je imalo značajno veću, a devet sorti značajno manju masu ploda. Na osnovu visoke rodnosti i velike krupnoće ploda, za gajenje u beogradskom području se mogu preporučiti sorte Blufri, Empres, Jojo, Nada, Prezident i Tophit.