Origin and domestication of Cucurbitaceae crops: insights from phylogenies, genomics and archaeology

Abstract

Summary Some of the World's most valuable crops, including watermelon, honey melon, cucumber, squash, zucchini and pumpkin, belong to the family Cucurbitaceae. We review insights on their domestication from new phylogenies, archaeology and genomic studies. Ancestral state estimation on the most complete Cucurbitaceae phylogeny to date suggests that an annual life cycle may have contributed to domestication. Domestication started c. 11 000 years ago in the New World and Asia, and apparently more recently in Africa. Some cucurbit crops were domesticated only once, others multiple times (e.g. melon from different Asian and African populations). Most wild cucurbit fruits are bitter and nonpalatable to humans, and nonbitterness of the pulp apparently was a trait favoured early during domestication, with genomic data showing how bitterness loss was achieved convergently. The genetic pathways underlying lycopene accumulation, red or orange pulp colour, and fruit size and shape are only just beginning to be understood. The study of cucurbit domestication in recent years has benefitted from the increasing integration of archaeological and genomic data with insights from herbarium collections, the most efficient way to understand species’ natural geographic ranges and climate adaptations.

Identification of Fruit-Associated QTLs in Winter Squash (Cucurbita maxima Duchesne) Using Recombinant Inbred Lines

“…This study describes the identification of QTLs for important fruit traits of C. maxima, which is the most diverse species of Cucurbita, characterized by fruit morphological complexity [7,11]. Certain cultivars of C. maxima produce one of the biggest fruits among all plants, which makes this cucurbit an interesting model plant to investigate genetic mechanisms underlying fruit size and its evolution [6,23]. In this study, advanced F 6 RILs were used to investigate nine agronomically important fruit-associated traits (Figure 1, Table 1).…”

“…It is an allotetraploid species with chromosome number 2n = 40 and a genome size estimated to be 386.8 Mb [1,2]. Currently, C. maxima is one of 10 Cucurbitaceae species of worldwide economic importance, and together with C. pepo and C. moschata, it is one of the three most important Cucurbita species [3][4][5][6].…”

“…Based on the fruit characteristics, seven major horticultural groups of C. maxima cultivars have been distinguished [11]. During domestication, C. maxima was selected for fruit size, and now the largest cucurbit fruits are produced by specific C. maxima cultivars (record fruits weigh up to 1000 kg) [6].…”

Phylogeographic and population genetic analyses ofCucurbita moschatareveal divergence of two mitochondrial lineages linked to an elevational gradient

“…Cucurbita pepo , C . maxima , and C. moschata are considered major crops of worldwide economic importance, as they are cultivated globally (Paris, ; Chomicki et al., ). For 2017 alone, the world production of pumpkins, squashes, and gourds was 28 million tons on 2 million ha.…”

“…Cultivated species comprise a large diversity of fruit shapes, including numerous landraces or varieties, as a result of their wide adaptability and popularity all over the world (OECD, 2012;Castellanos-Morales et al, 2018;Eguiarte et al, 2018). Cucurbita pepo, C. maxima, and C. moschata are considered major crops of worldwide economic importance, as they are cultivated globally (Paris, 2016;Chomicki et al, 2019). For 2017 alone, the world production of pumpkins, squashes, and gourds was 28 million tons on 2 million ha.…”