Abstract

  Climate resilient and high yielding Dwarf x Tall hybrids is the main strategy to meet increasing demand of coconut in a changing climate where sexual reproduction is susceptible to heat and drought stress (HTDS). Fruit set failures are mainly attributed to high sensitivity of pollen and ovules to stress, particularly around meiosis, in many crops. This study focused to assess the influence of heat (monthly mean Tmax > 330C) and water stress (monthly rainfall < 90 mm) around meiosis on the quality of pollen in San Ramon (SR) and Sri Lanka Tall (SLT) cultivars that used in controlled hybridization. We measured carbohydrates, germination (PG%) and tube length (PTL) in pollen developed under heat and/or drought stress and unstressed (control) around meiosis (final four months prior to flower opening).
San Ramon showed significantly higher PG% and PTL (43%, 517 μm respectively) compared to that of SLT (37%, 481 μm respectively) cultivar. Unstressed male flowers had significantly higher PG%, PTL and starch compared to flowers in stress at any stage around meiosis. The cumulative rainfall, number of dry days (rainfall < 3 mm/day), total number of heat stress days (Tmax < 330C) and average maximum temperature during the period around meiosis had merge impact on pollen starch (R2=0.96), total soluble sugar (TSS) (R2=0.71), pollen germination (PG%) (R2=0.61) and pollen tube length (PTL) (R2=0.89). The study concluded that heat and/or water stress around meiosis is very critical for pollen quality in two tested cultivars of coconut. This information will be of great importance to manipulate the pollination strategy to minimize stress-affected fruit set failures under controlled pollination.

Keywords: Coconut Hybrids; Flower Carbohydrates; Fruit Set; Heat and Water Stress; Pollen Germination

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Citation

Citation: KGAPK Amarasinghe., et al. “Influence of Heat and Water Stress Around Meiosis on Pollen Quality in Two Pollen Parents of Coconut (Cocos nucifera L.) Used in Control Hybridization in Sri Lanka". Acta Scientific Agriculture 4.12 (2020): 02-09.

Copyright

Copyright: © 2020 KGAPK Amarasinghe., et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.