Universidade Federal do Recôncavo da Bahia, Cruz das Almas, Bahia, Brasil.
Embrapa Mandioca e Fruticultura, Cruz das Almas, Bahia, Brasil.
PLoS One. 2023 Oct 5;18(10):e0292385. doi: 10.1371/journal.pone.0292385. eCollection 2023.
Cassava (Manihot esculenta Crantz) is a vital crop for food and economic security in many regions of the world. Despite the economic and social importance of cassava, challenges persist in developing superior varieties that meet the needs of farmers in terms of agronomic performance, nutritional quality, and resistance to pests and diseases. One of the main obstacles for genetic improvement is the lack of synchronization in flowering and the abortion of young flowers, making planned crosses and progeny production difficult. Therefore, the aim of this study was to evaluate the effect of photoperiod, premature pruning, and growth regulators on cassava flowering under low-altitude conditions in Brazil. Eight cassava clones with contrasting flowering capacity were assessed in Cruz das Almas, Bahia, using two photoperiods (ambient condition and extended photoperiod with red light for 12 hours), premature pruning at the first and second branching levels (with and without pruning), and the application of growth regulators: 0.5 mM 6-benzyladenine (BA) and 4.0 mM silver thiosulfate (STS) (with and without). Plots were assessed weekly for the number of female (NFF) and male (NMF) flowers, height of the first branching (H1B, in cm), number of days to the first branching (ND1B), and the number of branching events up to 240 days after planting (NOB). The extended photoperiod did not promote an increase in the number of flowers but allowed for precocity in cassava flowering, reducing the onset of flowering by up to 35 days, and significantly increasing the number of branches, which is closely related to flowering. The use of pruning and plant growth regulators (PGR) resulted in an increase in NFF from 2.2 (control) to 4.6 and NMF from 8.1 to 21.1 flowers. Therefore, under hot and humid tropical conditions at low altitudes in the Recôncavo of Bahia, manipulating the photoperiod and using premature pruning and plant growth regulators can accelerate cassava flowering, benefiting genetic improvement programs.
木薯（Manihot esculenta Crantz）是世界许多地区粮食和经济安全的重要作物。尽管木薯具有经济和社会重要性，但在开发满足农民在农艺性能、营养质量和抗病虫害方面需求的优良品种方面仍然存在挑战。遗传改良的主要障碍之一是开花缺乏同步性和幼花败育，使得计划的杂交和后代生产变得困难。因此，本研究旨在评估光周期、早期修剪和生长调节剂对巴西低海拔地区木薯开花的影响。在巴伊亚州的克鲁扎达斯阿尔马斯（Cruz das Almas），使用两种光周期（环境条件和延长光周期，其中红光延长 12 小时）、在第一和第二分枝水平进行早期修剪（修剪和不修剪）以及生长调节剂：0.5 mM 6-苄基腺嘌呤（BA）和 4.0 mM 银硫代硫酸（STS）（有和没有），对 8 个具有不同开花能力的木薯克隆进行了评估。每周评估一次雌性花（NFF）和雄性花（NMF）的数量、第一次分枝的高度（H1B，以厘米为单位）、第一次分枝的天数（ND1B）以及种植后 240 天内的分枝次数（NOB）。延长光周期并没有增加花的数量，但促进了木薯的早熟开花，使开花时间提前了多达 35 天，并显著增加了分枝数量，这与开花密切相关。使用修剪和植物生长调节剂（PGR）可使 NFF 从 2.2（对照）增加到 4.6，NMF 从 8.1 增加到 21.1。因此，在巴伊亚的雷孔卡沃低海拔地区炎热潮湿的热带条件下，操纵光周期并使用早期修剪和植物生长调节剂可以加速木薯开花，有利于遗传改良计划。
