The selection of pure lines followed by crosses to create superior hybrids is one of the oldest strategies in crop breeding. However, in domesticated species of the Capsicum genus hybrid breeding has lagged, in part due to a lack of detailed information about the phenotypic and metabolic consequences of hybridization. Here, we performed reciprocal crosses between four inbred varieties of two species of cultivated C. chinense (cv. Habanero and Biquinho) and C. annuum var. annuum (cv. Jalapeño and cv. Cascadura Ikeda). These varieties were specifically selected for their highly divergent traits, including plant growth habit, fruit size, shape and pungency: Habanero and Jalapeño peppers are highly pungent forms, particularly popular in Mexico. The Biquinho cultivar of C. chinense and the Cascadura Ikeda bell pepper are traditional sweet cultivars from Brazil. From the parental genotypes and from the progeny of the reciprocal crosses, we measured 28 phenotypic traits, including plant growth, and yield, 32 fruit shape parameters, and 50 fruit pericarp and placenta metabolites, including capsaicinoids. We found large differences for agronomic and metabolic traits between the genotypes, including heterosis for pungency and reciprocal effects for agronomic traits. We also show that the strong association between fruit shape and pungency can be broken in intraspecific hybrids, paving the way for the precision breeding of novel varieties.

中文翻译：

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通过杂交获得更辣的辣椒：杂种优势和互惠效应

选择纯品系然后进行杂交以产生优良的杂种是作物育种中最古老的策略之一。然而，在辣椒属的驯化物种中，杂交育种滞后，部分原因是缺乏关于杂交的表型和代谢结果的详细信息。在这里，我们进行了两种栽培的C. chinense（cv. Habanero 和 Biquinho）和C. annuum var. 的四个自交品种之间的互交。年鉴（简历。墨西哥胡椒和简历。卡斯卡杜拉池田）。这些品种是特别选择的，因为它们具有高度不同的特性，包括植物生长习性、果实大小、形状和辛辣度：哈瓦那辣椒和墨西哥辣椒是高度辛辣的形式，在墨西哥特别受欢迎。C. chinense的Biquinho栽培品种Cascadura Ikeda 甜椒是来自巴西的传统甜椒品种。从亲本基因型和互交后代中，我们测量了 28 个表型性状，包括植物生长和产量、32 个果实形状参数以及 50 个果皮和胎盘代谢物，包括辣椒素。我们发现基因型之间的农艺和代谢性状存在很大差异，包括辛辣性的杂种优势和农艺性状的相互影响。我们还表明，在种内杂交中可以打破果实形状和辛辣度之间的强烈关联，为新品种的精准育种铺平道路。