The dwarf gene Rht15 improved lodging resistance but differentially affected agronomic and quality traits in durum wheat

Abstract The dwarfing gene Rht15 in durum wheat is considered a GA-responsive dwarfing gene. To explore the use of Rht15 in durum wheat improvement, the effects of Rht15 on plant height, internode characteristics, lodging resistance, yield components and quality traits were evaluated by the Rht15 dwarf and tall F3:4, F4:5 and F5:6 lines derived from reciprocal crosses between “Durox” (Rht15) and “Langdon” (rht15). Rht15 significantly reduced plant height by 31.5 % on average by shortening the cell length. Furthermore, the diameter and wall thickness of internodes were significantly increased by Rht15, which decreased the height center of gravity (35.4 %), increased the mechanical strength of the basal internode (41.8 %), and finally improved the lodging resistance index (153.7 %). Rht15 reduced biomass plant−1 (-13.7 %), 1000-kernel weight (-12.9 %), grain number per spike (-2.3 %) and grain yield plant−1 (-10.3 %). However, Rht15 increased the grain protein content (8.7 %), wet gluten content (9.2 %) and starch content (2.3 %). In conclusion, Rht15 significantly reduced plant height and improved lodging resistance and some quality traits but had negative effects on some yield traits. Nonetheless, Rht15 has opened up an opportunity as an alternative dwarfing gene in wheat breeding and improvement.