Grain morphology, texture and colour-related compounds of bread wheat cultivars in relation to cultivation regimes and growing location

Abstract

Digital wheat grain classification systems are primarily based on kernel image and texture features. These traits are highly environment-dependent, so sample-to-sample variation may affect results of grain classification, grading, or discrimination. The main aim of this study was to determine the intra-cultivar variation of wheat kernel size, shape, colour, endosperm hardness and selected chemical compounds (carotenoids, phlobaphenes and proteins) associated with kernel colour. In the study, four winter bread wheat cultivars: two self-pollinated 'Bogatka' and 'Batuta' and two hybrid cultivars 'Hybred' and 'Hymack' were grown in different environments (extensive and intensive cultivation regimes, and three growing locations) to create variation in the kernel image, hardness and chemical compounds to simulate the range of variations encountered in reality. Measurements of kernel colour and dimensions were conducted using digital image analysis, hardness and protein content were analysed using nearinfrared reflectance (NIR) spectroscopy, while carotenoids and phlobaphenes were examined using colorimetric assays. The results showed that kernel dimensions and shape were highly intra-cultivar constant, with the highest variation of thickness (up to 7.59%) and volume (up to 10.10%). Surface colour was also relatively constant, with saturation as the most variable feature (up to 11.44%). In contrast, endosperm colour revealing an approx. 2-3-fold higher variation of colour attributes than surface colour, and the highest variation was observed in the case of saturation of the colour (up to 19.67%). Among the tested chemical compounds, carotenoids were the least intra-cultivar variable (up to 14.39%), while phlobaphenes the most intra-cultivar variable (up to 31.87%). Grain hardness was the most intra-cultivar variable feature of the tested grain samples and reached the highest value of 49.02% for cultivar 'Hymack'. The genotype had the greatest effect on kernel colour (up to 50.49% of the source of variation) and carotenoids (52.97%). The environment affected mostly the grain proteins (82.20%) and hardness (72.61%).

Teff Grain Physical and Chemical Quality Responses to Soil Physicochemical Properties and the Environment

“…Tańska et al [52] reported that variation in grain color of wheat was reflected by changes in its chemical composition but not the environment which is in partial agreement with the results of our study. In addition, the accumulation of carotenoids and anthocyanins pigments in wheat grain accounted for the large variation in its grain color [52][53][54][55] and may have played a role in the grain color differences for the single variety of teff sampled across multiple locations in our study. Overall, the average of 63.5% of the variation in grain color can be attributed to the variation in the soil physicochemical properties that influenced several parameters that were correlated with grain color in this study (Table 5).…”

High-Throughput Phenomic Characterization of Wheat Grain Architecture and Diversity for Conventional Morpho-Physiological Traits

“…The grain width, unproductive water use, grain area size, and grain volume showed maximum load for this PC indicating that these were the most variable traits. However, Tańska et al (2018) pointed out that the seed dimensions and shape were constant among the cultivars with highest variation shown by grain thickness and grain volume. The highest values for grain width, unproductive water use, grain size and grain volume indicated a positive correlation among these traits.…”

“…The grain size, shape and color variation have economic implications in bread wheat. These are the primary physical features that determine the market value of grain (Tańska et al 2018). The grain size is positively correlated with specific grain weight, a trait related to the efficiency of wheat transport and storage of photosynthates (Clarke et al 2004).…”

Crop Yield and Physicochemical Properties of Wheat Grains as Affected by Tillage Systems

“…Horvath and Veha [70] investigated the dependence of wheat grain color characteristics on the grain size. Tanska et al [71] investigated wheat grain color in relation to the cultivation regime.…”