Stay-green associates with low water soluble carbohydrates at flowering in oat

Abstract

High throughput phenotyping of canopy senescence based on Normalized Difference Vegetation Index (NDVI) could be useful in plant breeding. The aim of this paper was to assess the association between grain yield and canopy senescence quantified with NDVI in oat lines selected for grain yield and milling quality.Sixteen lines were grown in four winter-rainfall environments where logistic curves between NDVI and thermal time from anthesis (GS60) were fitted to return five traits: maximum NDVI, NDVImax; minimum NDVI, NDVImin; thermal time to 50% senescence, x50; rate of senescence, rate; and the area under the NDVI curve, area. Across sources of variation, residuals of yield after removing the effect of phenology correlated with area (r = 0.69), NDVImax (r = 0.67), x50 (r = 0.57), NDVImin (r = 0.51) and rate (r = −0.30), all significant at P < 0.05. All five senescence traits correlated negatively with concentration of water soluble carbohydrates at anthesis, particularly area (r = −0.75, P < 0.0001). There was no correlation for yield between environments in 5 out of 6 comparisons (broad sense heritability = 0.39) and water soluble carbohydrates correlated between environments in 6 out of 6 comparisons (broad sense heritability = 0.89). Correlations between environments were irregular for senescence traits. Selection for low concentration of water soluble carbohydrates could increase oat grain yield by improving both grain number per m2 and leaf area duration.