Effect of Prebloom Pruning on 13C and 15N Distribution during Early Spring in Sweet Cherry

Abstract

<jats:p>In sweet cherry, highly advanced dwarf combinations using ‘Gisela’ rootstocks promote higher productivity than do more vigorous combinations but require maintaining the leaf area to fruit area (LA:F) ratio. An experiment using double isotopic enrichment with <jats:sup>13</jats:sup>C and <jats:sup>15</jats:sup>N was carried out in 5-year-old ‘Bing’/‘GI 6’ trees in a commercial orchard located in Santa Cruz, Chile (34°39′S; 71°19′W), and characterized by a Mediterranean climate. Forty whole sweet cherry trees (TR<jats:sub>1</jats:sub>) trained as central axes were pruned in winter [July 20, 60 days before full bloom (DBFB)] and another 40 trees were left without pruning (TR<jats:sub>2</jats:sub>). A single <jats:sup>13</jats:sup>CO<jats:sub>2</jats:sub> pulse and <jats:sup>15</jats:sup>N-urea application to the mature leaves of individual 4-year-old branches on trees of both TRs was carried out during stage III (SIII). Winter pruning reduced yield by 44%, improved fruit quality [i.e., size, weight, and soluble solids content (SSC)] and induced the growth of extension shoots (ES) (i.e., number, length, and LA). For both TRs, fruits were stronger sinks for <jats:sup>13</jats:sup>C-photoassimilates and <jats:sup>15</jats:sup>N than were ES. ES of pruned trees had higher sink strength than ES of unpruned trees. Pruned trees developed more ES that were longer and that had higher LA compared with the ES of unpruned trees.</jats:p>

Pruning terms and techniques affect vigour and flower formation of Ukrainian sweet cherry trees

“…Our study observed a reduction of shoot length on the trees pruned less severely, which was also documented in other studies (Usenik et al, 2008;Villasante et al, 2012), and may be explained by bet ter nitrogen use efficiency by extension shoots on pruned branches (Ayala et al, 2018). 'Krupnoplidna' trees also had decreased values of this indicator when pruned in late summer compared to dormancy.…”

“…The results of this study are consistent with other trials on sweet cherry that report a yield increase when trees were unpruned or lightly pruned (Villasante et al, 2012;Claverie and Lauri, 2005). However, it should be noted that when trees enter full bearing, low pruning severity has a negative effect on fruit size and thus marketability of the yield (Gonkiewicz, 2011;von Bennewitz et al, 2011;Ayala et al, 2018), so more aggressive pruning may be need ed to manage crop load and maintain fruit quality.…”