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Denardi F.,Epagri Cacador Experimental Station | Berton O.,Epagri Cacador Experimental Station | Stuker H.,Epagri Itajai Experimental Station
Acta Horticulturae | Year: 2010

Around the World many investigations have already been done to overcome the challenge of the long juvenile period of apple seedlings. To collaborate with apple breeders, a study has been done at Epagri/Caçador Experimental Station in order to investigate the correlation between some parameters of tree growth habit with juvenility phase on apple, expressed as flowering index - FI. After three and a half years from seed germination, a total of 1.287 pre-selections from eight apple progenies grafted on Marubakaido/M-9 inter-stem have been investigated. The following variables were evaluated: a) plant height - PH; b) length of the last annual growth of the leader - AGL; c) length of the internodes - IL; d) type of leader - TL. Only for TL a reasonable good correlation with FI was observed. There was significant negative correlation between length/thinness of the leader and intensity of blooming on all the eight apple progenies studied. The correlation values varied from R=0,27 for the progeny 'Imperatriz' × 'Fred Hough' to R=0,49 for 'Imperatriz' × M-46/94, 'Imperatriz' × 'Catarina' and 'Imperatriz' × 'Baronesa', with an average value of R=0,44. For all the other variables, the correlation was very poor, even not significant in most cases. For plant height, mentioned in the literature as a good parameter for selecting apple seedlings to shorten juvenile period, not only a very poor correlation with FI was observed, but even some negative correlation between both. The average for all progenies for this parameter was R=0,07 only, being not significant. For internodes length, even showing a negative correlation for all progenies as expected, the correlation values were highly variable. The highest negative correlation was observed for the progeny 'Imperatriz' × M-46/94 - R=-0,42 -and the poorest for the progeny M-72/90 × 'Gala' - R=-0,017. These results indicate that for apple progenies grafted on Marubakaido/M-9 inter-stem, the only criterion that offers a certain guarantee for pre-selections leading to a short juvenile period on apple seedlings seems to be the type of leader.

Petri J.L.,Epagri Cacador Experimental Station | Berenhauser-Leite G.,Epagri Cacador Experimental Station | Hawerroth F.J.,Epagri Cacador Experimental Station | Basso C.,Epagri Cacador Experimental Station
Acta Horticulturae | Year: 2011

The mild climate and extended growing season of Brazil results in more shoots growth on semi-dwarfing apple trees than in other apple growing areas of the world. We conducted several experiments from 2005 to 2007 with Prohexadione Ca to evaluate its potential to reduce shoot growth and pruning labor. When Prohexadione Ca was applied twice per season (20 and 50 days after full bloom) at 320 g ha -1, shoot length and shoot number of 'Gala' and 'Fuji' on M.7 rootstock was reduced significantly as well as the number of shoots removed by winter pruning. The reduction in shoot numbers was more pronounced than the reduction in shoot length. Yield after two years of application was also increased by applications of Prohexadione Ca. Prohexadione Ca also effectively reduced growth in a two-year old apple orchard when applied after bloom.

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