Starkus Aurelijus, Frercks Birute, Gelvonauskiene Dalia, Mazeikiene Ingrida, Rugienius Rytis, Bendokas Vidmantas, Stanys Vidmantas
Lithuanian Research Centre for Agriculture and Forestry, Department of Orchard Plant Genetics and Biotechnology, Institute of Horticulture, Babtai, LT-54333 Kaunas, Lithuania.
Plants (Basel). 2021 Aug 5;10(8):1612. doi: 10.3390/plants10081612.
The heavy blooming of apple trees results in the inefficient usage of energy and nutritional material, and additional expenditure on fruitlet thinning is required to maintain fruit quality. A possible solution for controlling the fruit load on trees is the development of new cultivars that self-eliminate excess fruitlets, thus controlling yield. The aim of our study was to identify biological differences in apple cultivars in terms of blooming intensity and fruitlet load self-regulation. In total, 19 apple cultivars were studied in the years 2015-2017. The dynamics of fruitlet self-elimination, seed development in fruitlets and fruits, photosynthetic parameters, carbohydrates, and plant hormones were evaluated. We established that apple cultivars self-eliminating a small number of fruitlets need a lower number of well-developed seeds in fruit, and their number of leaves and area per fruit on a bearing branch are larger, compared to cultivars, self-eliminating large numbers of fruitlets. A higher carbohydrate amount in the leaves may be related to smaller fruitlet self-elimination. The amount of auxin and a high indole-3-acetic acid/zeatin ratio between leaves of cultivar groups with heavy blooming were higher than in cultivars with moderate blooming. A lower amount of abscisic acid was found in heavy-blooming cultivars during drought stress. All these parameters may be used as markers for the selection of different apple genotypes that self-eliminate fruitlets.
苹果树的大量开花导致能量和营养物质的低效利用，并且需要额外的疏果支出以维持果实品质。控制树体果实负载量的一个可能解决方案是培育能够自我消除过多幼果从而控制产量的新品种。我们研究的目的是确定苹果品种在开花强度和幼果负载自我调节方面的生物学差异。在2015年至2017年期间，总共研究了19个苹果品种。评估了幼果自我消除的动态、幼果和果实中的种子发育、光合参数、碳水化合物和植物激素。我们发现，与自我消除大量幼果的品种相比，自我消除少量幼果的苹果品种果实中发育良好的种子数量较少，其结果枝上每个果实的叶片数量和面积更大。叶片中较高的碳水化合物含量可能与较少的幼果自我消除有关。大量开花的品种组叶片中的生长素含量以及高吲哚-3-乙酸/玉米素比率高于中等开花的品种。在干旱胁迫期间，大量开花的品种中脱落酸含量较低。所有这些参数都可以用作选择能够自我消除幼果的不同苹果基因型的标记。
