By wind or wing: pollination syndromes and alternate bearing in horticultural systems

Abstract

Cyclical fluctuations in reproductive output are widespread among perennial plants, from multi-year masting cycles in forest trees to alternate bearing in horticultural crops. In natural systems, ecological drivers such as climate and pollen limitation can result in synchrony among plants. Agricultural practices are generally assumed to outweigh ecological drivers that might synchronize alternate-bearing individuals, but this assumption has not been rigorously assessed and little is known about the role of pollen limitation as a driver of synchrony in alternate-bearing crops. We tested whether alternate-bearing perennial crops show signs of alternate bearing at a national scale and whether the magnitude of national-scale alternate bearing differs across pollination syndromes. We analysed the Food and Agriculture Organization of the United Nations time series (1961–2018) of national crop yields across the top-producing countries of 27 alternate-bearing taxa, 6 wind-pollinated and 21 insect-pollinated. Alternate bearing was common in these national data and more pronounced in wind-pollinated taxa, which exhibited a more negative lag-1 autocorrelation and a higher coefficient of variation (CV). We highlight the mutual benefits of integrating ecological theory and agricultural data for (i) advancing our understanding of perennial plant reproduction across time, space and taxa, and (ii) promoting stable farmer livelihoods and global food supply. This article is part of the theme issue ‘The ecology and evolution of synchronized seed production in plants’.

Yield and nut characteristics of hazelnut genotypes grown in San Joaquin Valley, California

“…(2017) reported that Corylus trees are commercially productive in Season 4. Hazelnut yield fluctuation between years, with a lower yield in a consecutive year, was reported in literature (Xu & Hanna, 2010; Garcia et al., 2021). In our study, the nut yield in Season 6 increased for 50 accessions except for three cultivars (Gem, Ennis, and Butler; difference of 939, 307, 984 g, respectively).…”

The ecology and evolution of synchronized reproduction in long-lived plants

“…As this problem is overcome, it is likely that our understanding of the evolution of masting seeding could drastically change. For example, in several parts of the world, synchronous, community-wide mass flowering and fruiting events in wild and domestic plants have been observed [2,38], while in other places, even closely related plant species produce seed crops on their own schedule [89]. These patterns remain a mystery, and one that may be addressed with future phylogenetic analyses.…”

“…Furthermore, patterns present in wild masting species, such as higher interannual variation in wind-pollinated species compared to animal-pollinated, are also present in horticultural systems. This has diverse consequences for the global food supply and farmer livelihoods, as discussed in this issue by Garcia et al [2]. Fundamentally, masting creates year-to-year variation that has important ecosystem consequences.…”

“…In the Anthropocene, the focus has also shifted to controlling invasive plants and animals, forecasting the risk of zoonotic diseases that cycle with mast crops, and collecting seeds for food [5], as masting also occurs in many cultivated fruit and nut crops. In agriculture, this phenomenon is usually known as 'alternate cropping' or 'alternate bearing' and is characteristic of many commonly grown fruit crops, including apples, cherries and chestnuts [2]. Furthermore, patterns present in wild masting species, such as higher interannual variation in wind-pollinated species compared to animal-pollinated, are also present in horticultural systems.…”

“…The relationship between weather and resource dynamics, such as crop fluctuations and plant regeneration, likely constituted some of the earliest ecological knowledge passed over generations, particularly before such dynamics were stabilized with the onset of agriculture [1]. For humans, the importance of extensive temporal variation and spatial synchrony in seed production within and across plant populations-a phenomenon broadly termed masting or mast seeding-has transitioned from a matter of survival, starvation or migration to one of arboriculture, forestry, wildlife management, conservation and disease prevention [2][3][4][5].…”