Underground heterosis for yield improvement in melon. (16th May 2021)

• Record Type: Journal Article
• Authors: Dafna, Asaf; Halperin, Ilan; Oren, Elad; Isaacson, Tal; Tzuri, Galil; Meir, Ayala; Schaffer, Arthur A; Burger, Joseph; Tadmor, Yaakov; Buckler, Edward S; Gur, Amit
• Editors: Costa, Fabrizio
• Is Part Of: Journal of experimental botany. Volume 72:Number 18(2021)
• Page Start: 6205
• Page End: 6218
• Publication Date: 2021-05-16
• Subjects: Cucumis melo -- grafting -- genome-wide association study (GWAS) -- half-diallel -- heterosis -- rootstock -- whole-genome resequencing (WGS) -- yield; Botany -- Periodicals; Botany, Experimental -- Periodicals; Plant physiology -- Periodicals; 580
• DOI: 10.1093/jxb/erab219
• Languages: English
• ISSNs: 0022-0957

Abstract

Abstract: Heterosis, the superiority of hybrids over their parents, is a major genetic force associated with plant fitness and crop yield enhancement. We investigated root-mediated yield heterosis in melons ( Cucumis melo ) by characterizing a common variety grafted onto 190 hybrid rootstocks, resulting from crossing 20 diverse inbreds in a diallel-mating scheme. Hybrid rootstocks improved yield by more than 40% compared with their parents, and the best hybrid yield outperformed the reference commercial variety by 65% under both optimal and minimal irrigation treatments. To characterize the genetics of underground heterosis we conducted whole genome re-sequencing of the 20 founder lines, and showed that parental genetic distance was no predictor for the level of heterosis. Through inference of the 190 hybrid genotypes from their parental genomes, followed by genome-wide association analysis, we mapped multiple quantitative trait loci for root-mediated yield. Yield enhancement of the four best-performing hybrid rootstocks was validated in multiple experiments with four different scion varieties. Our grafting approach is complementary to the common roots genetic approach that focuses mainly on variation in root system architecture, and is a step towards discovery of candidate genes involved in root function and yield enhancement. Abstract : Yield heterosis in melon is controlled independently above and underground. Common-scion grafting reveals that heritable rootstock-mediated variation in a diallel population is associated with substantial fruit yield heterosis.