Possible mechanisms of pollination failure in hybrid carrot seed and implications for industry in a changing climate

Abstract

Approximately one-third of our food globally comes from insect-pollinated crops. The dependence on pollinators has been linked to yield instability, which could potentially become worse in a changing climate. Insect-pollinated crops produced via hybrid breeding (20% of fruit and vegetable production globally) are especially at risk as they are even more reliant on pollinators than open-pollinated plants. We already observe a wide range of fruit and seed yields between different cultivars of the same crop species, and it is unknown how existing variation will be affected in a changing climate. In this study, we examined how three hybrid carrot varieties with differential performance in the field responded to three temperature regimes (cooler than the historical average, average, and warmer that the historical average). We tested how temperature affected the plants' ability to set seed (seed set, pollen viability) as well as attract pollinators (nectar composition, floral volatiles). We found that there were significant intrinsic differences in nectar phenolics, pollen viability, and seed set between the carrot varieties, and that higher temperatures did not exaggerate those differences. However, elevated temperature did negatively affect several characteristics relating to the attraction and reward of pollinators (lower volatile production and higher nectar sugar concentration) across all varieties, which may decrease the attractiveness of this already pollinator-limited crop. Given existing predictions of lower pollinator populations in a warmer climate, reduced attractiveness would add yet another challenge to future food production.

A Floral Diet Increases the Longevity of the Coccinellid Adalia bipunctata but Does Not Allow Molting or Reproduction

“…Feeding on D. carota flowers can selectively benefit some insects, such as the parasitoid Cotesia glomerata (Winkler et al, 2009), while some others such as the lacewing Chrysoperla carnea and the herbivore Pieris rapae (Lepidoptera: Pieridae) do not benefit (Winkler et al, 2009;Gonzalez et al, 2016). The nectar is accessible and dominated by glucose and fructose (Broussard et al, 2017) but A. bipunctata larvae did not benefit from D. carota flowers in this study. The reasons for the poor performance of A. bipunctata larvae provided with M. chamomilla and D. carota flower diets, as well as for the poor performance of larvae on pure pollen diets remain speculative but are consistent with the central role of sugars for A. bipunctata survival in the absence of prey.…”

Influence of source and scale of gridded temperature data on modelled spring onset patterns in the conterminous United States

“…Such shifts have significant ecological, hydrological, and economic consequences. When plants leaf and bloom earlier than normal, for example, pollinators and herbivores, have to adjust their life cycle events (Marra et al ., ; Miller‐Rushing et al ., ; Gornish and Tylianakis, ; Broussard et al ., ). Earlier leaf‐out can dry out soils and advance, and even exacerbate, the wildfire season (Abatzoglou and Williams, ).…”

Cross-compatibility of five highbush blueberry varieties and ideal crossing combinations

“…Growers therefore persistently seek innovative ways to improve pest-control, plant nutrition, and irrigation to overcome these problems and increase yields (Bodner et al, 2015;Isman, 2000;Kumar et al, 2008;Mueller et al, 2012). Yet, even when fertigation and pest-control are ideally managed, many crops may still fail to produce optimal yields if they are not adequately pollinated (Broussard et al, 2017;Fijen et al, 2018). Growers of animal-pollinated crops therefore need to manage an additional dimension of crop production-pollination services-to ensure that enough of the correct pollen lands on recipient stigmas (Eaton and Nams, 2012;Gaines-Day and Gratton, 2016;Stern et al, 2001).…”