Shading in the late stem elongation period generate the greatest grain yield reduction in oat (Avena sativa L.)

ABSTRACT

This study was carried out to determine the critical period in oats, which is relevant for locating that period under the best climatic conditions. Trials were conducted in the Argentinian Pampas during 2015–2016, using four oat genotypes with different growing cycle. The experimental design was a split-split-plot, with three replications; being genotypes the main plot and the subplots six shading treatments [unshaded control and five shaded treatments during 25 days, from different growth stages [GS31 (first-visible-node), GS32, GS33, GS40 (boot), and GS60 (flowering)]. GY and its components [(number of panicles (NP), grains number per panicles (GNP), grains number per square meter (GN), and thousand kernel weight (TKW)] were determined at harvest. GY was sensitive to radiation limitations, showing falls of 20 to 70%, varying according to shading and genotypes. The shading mainly affected GY between GS32 and a few days after flowering in the short-intermediate cycle genotypes, and from GS33 in those with the longest cycles. Regression analysis showed that GN was the most affected yield component, being GNP more sensitive to stress and closely related to GN than NP. TKW showed less magnitude reductions (4.6 to 17.4%), being the shading at GS40, the one that caused the greatest decreases.

KEYWORDS:

• Shading
• panicles weight at flowering
• grain number
• thousand kernel weight
• grain yield

Acknowledgements

We wish to thank the staff from the J. Hirschhorn Experimental Station (FCAyF-UNLP). M.S appreciates the support received by Georg Forster Fellowship from Alexander von Humboldt Foundation.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was funded by projects from ANPCyT (PICT 2940-2019); UNLP (350-16) and UNLP (A352-19).