Genetic cornerstones of grain yield determination in spike-branching wheat (Triticum turgidum L.)

Abstract

Introducing variations in inflorescence architecture, such as the 'Miracle-Wheat' (Triticum turgidum convar. compositum (L.f.) Filat.) with a branching spike, has relevance for enhancing wheat grain yield. However, in the spike-branching genotypes, the increase in spikelet number is not translated into higher grain yield due to reduced grains per spikelet and shorter grains. Here, we investigated if such trade-offs might be a function of source-sink strength by using 385 RILs developed by intercrossing the spike-branching landrace TRI 984 and CIRNO, an elite durum (T. durum L.) cultivar. Our multi-year field phenotyping and robust genetic analysis revealed key favorable allele combinations viz., branched headt 3 (bht-A3), grain protein content (gpc-B1) that delayed senescence and QSL.ipk-4AL (longer spike and grains) increased grain number and grain weight in spike-branching wheat, suggesting the importance of a stronger source-sink balance for actualizing its potential.

Variationen in Blütenstandarchitektur, wie z. B. „Wunderweizen“ (Triticum turgidum convar. compositum (L.f.) Filat.), steigern den Weizenertrag. Ährenverzweigung erhöht nicht automatisch den Ertrag, da Körner kleiner sind. Mehrjährige Felduntersuchungen mit 385 RILs aus der Kreuzung mit einer ährenverzweigenden Landrasse TRI 984 und CIRNO (T. durum L.; Durum-Elitesorte) zeigen günstige Allel-Kombinationen wie branched headt 3 (bht-A3), grain protein content (gpc-B1) und QSL.ipk-4AL (längere Ähre und Körner). Diese fördern das Source-Sink-Gleichgewicht und verbessern Kornzahl und -gewicht bei ährenverzweigendem Weizen.