Apple trees, eight-year-old ‘Gala’/M.9 and four-year-old ‘Golden Delicious’/M.9 have been thinned with 6-
benzyladenine (BA) 50 ppm, 100 ppm and 200 ppm, with 1-naphthaleneacetic acid (NAA) 5 ppm, 10 ppm
and 20 ppm, and with the tank mix combinations of BA 50 ppm + NAA 5 ppm or BA 20 ppm + NAA 5 ppm,
all at 9-10 mm fruitlet diameter. All applied concentrations of BA and NAA thinned both cultivars
significantly and no significant difference was found between BA or NAA thinning action. No concentration
response on thinning was observed with neither BA nor NAA application. All BA or NAA separate treatments
caused yield of fruit to shift to bigger size class. The only concentration response effect was found on
evaluation of mean fruit weight data on ‘Golden Delicious’. The higher concentration of BA was used, the
higher was the weight of ‘Golden Delicious’ fruit. On the opposite, the higher concentration of NAA was used,
the lower was the weight of ‘Golden Delicious’ fruit (not significantly). When BA and NAA were sprayed on
‘Gala’ or ‘Golden Delicious’ as a tank mix combination, similar effect on thinning or fruit growth occurred
comparing to BA or NAA when sprayed alone. Return bloom was enhanced on all thinned ‘Gala’ trees while
flower formation of ‘Golden Delicious’ was better in the case of BA 200 ppm, NAA 5 ppm, NAA 20 ppm or
tank mix spraying of BA 20 ppm + NAA 5 ppm.Sedem let stare jablane sorte Gala/M.9 in štiri leta stare jablane sorte Zlati delišes/M.9 smo redčili s 6-
benziladeninom (BA) v koncentraciji 50 ppm, 100 ppm in 200 ppm, nadalje z 1-naftilocetno kislino (NAA) v
koncentraciji 5 ppm, 10 ppm in 20 ppm, ter s kombinacijo obeh sredstev, to je z mešanico BA 50 ppm + NAA
5 ppm, ter BA 20 ppm + NAA 5 ppm. Sredstva za redčenje smo nanesli v času poprečnega premera plodičev
9-10 mm. BA in NAA sta redčili obe preskušani sorti značilno in s približno isto stopnjo trebljenja plodičev.
Trebljenje plodičev po nanosu različnih koncentracij BA oziroma NAA ni bilo odvisno od uporabljenih
koncentracij. Pridelek plodov večjega velikostnega razreda se je pri obeh sortah povečal pri vseh nanosih BA
ali NAA. Pri sorti Zlati delišes smo opazili učinek koncentracij uporabljenega sredstva na poprečno težo
plodov. Po nanosu večje koncentracije BA je bila tudi poprečna teža plodov sorte Zlati delišes večja. Obratno
pa je nanos večje koncentracije NAA povzročil manjšo poprečno težo plodov (statistično neznačilno) sorte
Zlati delišes. V primeru škropljenja mešanice BA + NAA, sta obe obravnavani sorti reagirali z enako
intenziteto trebljenja plodičev, kot v primeru samostojnega nanosa enega od obeh sredstev. Povratno cvetenje
je bilo značilno boljše pri vseh redčenih drevesih sorte Gala, pri sorti Zlati delišes pa se je nastavek cvetja
izboljšal le po nanosih BA 200 ppm, NAA 5 ppm, NAA 20 ppm in pri mešanici BA 20 ppm + NAA 5 ppm
