# Effect of Awns on Photosynthesis and Yield of Triticale Under Water Deficit Compared to Flag Leaves

## TL;DR

This study shows that triticale with awns performs better under drought during grain filling compared to awnless triticale.

## Contribution

The novel finding is the critical role of awns in mitigating drought effects on photosynthesis and yield in triticale.

## Key findings

- Awns showed less photosynthesis reduction under drought compared to flag leaves.
- Water deficit reduced grain yield by 23.7% in awned and 24.6% in awnless triticale.
- Awns helped maintain higher relative water content and chlorophyll under drought.

## Abstract

Water deficit during the grain filling stage is a major threat to sustainable crop production, especially in arid and semi-arid regions. This study aims to investigate the comprehensive effects of water deficit on the photosynthetic characteristics, dry matter accumulation, and yield formation of triticale (× Triticosecale wittmack). The photosynthetic characteristics of the flag leaf and spike organs (awn, glume, and lemma) and their relationship with yield were analyzed during the grain filling stage when the triticale plant was subjected to adequate water supply and water deficit 0, 7, 14, 20, and 25 days after anthesis. The results showed that under normal water supply, photosynthesis was reduced by 27.5% and 34.4% in awned and awnless spikes, respectively, at 25 days after anthesis (25DAAs), compared to flag leaves. Under water deficit at 25DAAs, photosynthesis was reduced by 50.5% and 60.9% in awned and awnless spikes, respectively. Water deficit reduced RWC and chlorophyll content in flag leaf and spike organs, and the changes in RWC and chlorophyll content in spike organs were less than those in flag leaf. The differences in grain yield, biomass, and harvest index of awned and awnless triticale were not significant under adequate water supply. Grain yield of awned and awnless triticale was reduced by 23.7 and 24.6%, respectively, under water deficit compared to adequate water supply. Our results suggest that awnless plants suffer from drought more than awned plants in grain-filling stage, where the role of awns is critical.