Effects of Timing and Intensity of Summer Pruning on Vegetative Traits of Two Southern Highbush Blueberry Cultivars

Abstract

<jats:p>Pruning is a recommended practice for blueberry (<jats:italic>Vaccinium</jats:italic> spp.) production and is usually done in the summer in warm subtropical climates with long growing seasons. Summer pruning promotes healthy vegetative growth during the remainder of the growing season; however, research-based recommendations for summer pruning strategies are lacking. The objective of this study was to determine effects of summer pruning timing and intensity on vegetative growth in ‘Jewel’ and ‘Emerald’ southern highbush blueberry (<jats:italic>V. corymbosum-</jats:italic>interspecific hybrid), two cultivars of the primary species grown in subtropical areas. To determine effects of pruning time, 30% of the canopy was removed in June or July. To determine pruning intensity effects, either 30% or 60% of the canopy was removed in June, both followed by shoot tipping in July. Both timing and intensity treatments were compared with a non-pruned control. Lack of pruning in the first year had no negative effects on growth; however, lack of pruning for two or more seasons decreased regrowth volume and shoot length of both cultivars. By the third season, canopy regrowth volume in both cultivars decreased in the non-pruned control compared with the 30% and 60% pruning treatments and compared with the June pruning treatment. Disease infection in ‘Jewel’ was also increased in the non-pruned control compared with these pruning treatments. Summer pruning, regardless of timing or intensity, generally increased vigor of vegetative growth for both cultivars and decreased incidence of leaf disease in ‘Jewel’.</jats:p>

Effects of Timing and Intensity of Summer Pruning on Reproductive Traits of Two Southern Highbush Blueberry Cultivars

“…Wint. )]-in response to the pruning treatment (Kovaleski et al, 2015a). Ojiambo et al (2006) found that leaf spots and defoliation decreased inflorescence bud formation and yield in rabbiteye and SHB, as did for SHB.…”

“…Ojiambo et al (2006) found that leaf spots and defoliation decreased inflorescence bud formation and yield in rabbiteye and SHB, as did for SHB. However, other factors are also involved in inflorescence bud initiation, as the 60% pruning treatment in 'Jewel' had similar levels of leaf disease and defoliation as the 30% pruning treatment (Kovaleski et al, 2015a), but inflorescence bud number per plant was not different from the nonpruned control. This may be an effect of the decreased canopy volume in the heavy pruned plants compared with moderate and nonpruned plants (Kovaleski et al, 2015a).…”

“…SHB (V. corymbosum interspecific hybrid) is the major species of blueberry grown in Florida and other mild winter areas. High temperatures and a long-growing season characterize the climate where SHB are typically grown, and summer pruning after fruit harvest stimulates healthy vegetative growth through the end of the growing season by removing older foliage that would otherwise serve as source of inoculum for leaf diseases (Kovaleski et al, 2015a;Patten et al, 1991;. This is important as the fall foliage supports inflorescence bud development and increases carbohydrate reserve accumulation to support early fruit development the following growing season (Lyrene, 1992;Darnell, 2001, 2002;.…”

Fisiologia de mirtileiros de baixa exigência em frio, cultivados em região subtropical

“…Seu porte arbustivo é vigoroso, podendo chegar a 1,0 m de altura e na Flórida, onde tem sido cultivada, floresce em meados de fevereiro e produz em meados de abril a maio. Seus frutos tendem a ser menores que os de 'Emerald', podendo chegar a até 2,5 gramas, com qualidade suficiente para aceitação no mercado (KOVALESKI et al, 2015;LYRENE, 2001b).…”

“…A produção do mirtileiro pode variar de acordo com a cultivar, idade das plantas, região na qual estão implantadas e pelos tratos culturais adotados KOVALESKI et al, 2015). Na Flórida, mirtileiros do subgrupo Southern Highbush cultivados em campo, no espaçamento de 0,90 x 2,7 metros, obtiveram produção entre 3,78 a 6,22 kg planta -1 , dependendo do tipo e época da poda realizada (KOVALESKI et al, 2015).…”