ABSTRACT

Self-compatibility is a key trait in cocoa Nacional (CN) clones to secure self-pollination (SP). However, SP in CN clones has not been assessed for tolerance to ENSO elicited soil waterlogging. Therefore, the aim of this investigation was to analyse the impact of ENSO on SP and cross-pollination (CP) effectiveness in ten CN L-H encoded clones, the SP clone CN EET-103 and the Trinitario CNN-51. In the 2016 season that followed an ENSO event, the L21-H43 and L29-H04 clones showed 1.2 fold higher index of self-compatibility (ISC >0.92) than CNN-51 and EET-103, and were categorised as waterlogging tolerant. In contrast, the remaining eight L-H clones had the lowest SP, CP and ISC in 2016, and were considered waterlogging sensitive. This is the first report on the hindering effects of ENSO on SC and CP in waterlogging-sensitive CN clones, and on the existence of the waterlogging tolerance trait in two L-H clones. Based on the present results, soil anoxia must be included among the constraints hindering cocoa productivity, and waterlogging tolerance should be a trait considered by cocoa breeders. Self-compatible and waterlogging tolerant CN clones with higher SP, CP and ISC can add value to cocoa plantations that are vulnerable to ENSO conditions.

摘要

自相容性是可可国家（CN）克隆中确保自花授粉（SP）的关键特征。然而，尚未评估 CN 无性系中的 SP 对 ENSO 引起的土壤涝渍的耐受性。因此，本研究的目的是分析 ENSO 对 10 个 CN LH 编码克隆、SP 克隆 CN EET-103 和 Trinitario CNN-51 中 SP 和异花授粉 (CP) 有效性的影响。在 ENSO 事件之后的 2016 年季节，L21-H43 和 L29-H04 克隆的自相容指数（ISC > 0.92）比 CNN-51 和 EET-103 高 1.2 倍，被归类为耐涝。相比之下，其余 8 个 LH 克隆在 2016 年的 SP、CP 和 ISC 最低，被认为是涝渍敏感的。这是第一份关于 ENSO 对淹水敏感 CN 克隆中 SC 和 CP 的阻碍作用的报告，以及两个 LH 无性系中耐涝性状的存在。根据目前的结果，土壤缺氧必须包括在阻碍可可生产力的限制因素中，耐涝性应该是可可育种者考虑的一个特征。具有较高 SP、CP 和 ISC 的自相容和耐涝 CN 克隆可以为易受 ENSO 条件影响的可可种植园增加价值。