Peach flower bud development. Peach flower bud development

Thinning is indispensable practice in peach cultivation aiming to reduce fruit number per plant, promoting sink-source balance and reducing competition among fruit, which results in bigger fruit and the improvement of other fruit-quality parameters. Inhibition of floral induction by GAs has been largely demonstrated and commercial products based on GAs have been used to this aim. We tested a product GA4/7 based in different moments after full bloom in peach to reduce the number of flowers in the following season. Return to bloom and transcriptome analysis were performed to identify the best moment for the treatment, increasing the product efficacy and understanding the product action at genetic level. Overall design: The main field trial has been carried out in 2019 on the flat-nectarine cultivar Platinet 1 (Prunus persica var. platycarpa). This cultivar is harvested approximately 22 days before the reference cv RedHaven. The experiment was conducted at Vivai Zanzi’s farm in Ferrara, Italy (44°46’56.355”, 11°39’55.419”). A suitable number of homogeneous trees with a suitable fruit load, all protected by anti-hail nets, were selected and marked among 40 trees in total in order to build a single block experiment with 5 trees per block. Blocks were separated by two untreated trees to avoid drift effects. The experimental formulation FAL900 (10 g/L GA7) was sprayed at 100 ppm by using a shoulder sprayer until run-off, at 45 (T1), 51 (T2), 58 (T3), 65 (T4), and 79 (T5) days after full bloom (DAFB). Before spraying, a suitable number of shoots were collected in three biological replicates and the buds from the top and the bottom halves of the shoot excised separately, frozen in liquid nitrogen and stored at -80°C for following analyses.

疏果是桃树栽培中不可或缺的作业，其核心目标为降低单株挂果量，促进库源平衡（sink-source balance），减轻果实间的资源竞争，最终实现果实膨大并改善其余果实品质性状。
赤霉素（GAs）抑制成花诱导的效应已得到广泛证实，基于赤霉素的商用制剂也已被应用于该调控需求。
本研究以GA4/7制剂为试材，在桃树盛花后不同时段施药，以期降低翌年的开花总量。
我们通过返花观测与转录组（transcriptome）分析，筛选最佳施药时段，以提升制剂的施用效果，并解析该制剂在遗传层面的作用机制。
整体试验设计：本项主要田间试验于2019年在扁油桃品种‘Platinet 1’（Prunus persica var. platycarpa）上开展。该品种的采收期较对照品种‘RedHaven’早约22天。试验地点位于意大利费拉拉的Vivai Zanzi农场，地理坐标为44°46′56.355″，11°39′55.419″。从总计40棵桃树中挑选长势一致、负载量适宜的个体，所有植株均覆盖防雹网，标记后组建区组试验，每个区组包含5棵树。区组之间设置2棵未施药树作为隔离带，以避免药剂漂移产生的干扰。试验制剂FAL900（含10 g/L GA7）以100 ppm的浓度通过背负式喷雾器喷施至植株药液滴水为止，施药时间分别为盛花后45天（T1）、51天（T2）、58天（T3）、65天（T4）及79天（T5，DAFB）。施药前，采集适量枝条设置3个生物学重复（biological replicates），分别剥离枝条顶部与基部的芽体，经液氮速冻后保存于-80℃冰箱，用于后续分析。