Interpretation of yield and quality traits of barley (Hordeum vulgare L.) varieties by heatmap technique

Background

Barley (Hordeum vulgare L.) is the most cultivated cool-season cereal after wheat in Türkiye. This can be attributed to its uses in the malt industry, human consumption, and animal nutrition etc. This study investigated yield, physiological, and quality traits of different barley varieties using heatmap and principal component analysis (PCA) technique to identify the varieties with better yield and superior quality.

Methods

A total of 12 barley varieties (8 two-row and 4 six-row) were used in the study. The varieties were sown under natural conditions and data relating to yield, phenology and quality traits (grain yield, heading time, plant height, number of spikes m⁻², 1000-grain weight, and starch ratio) were recorded. The recorded data were analyzed by PCA and heatmap techniques to determine the better-performing varieties.

Results

Significant variations were observed among the tested varieties for all evaluated traits (p < 0.01). Heatmap categorized the recorded traits into two clusters, and traits within the same cluster exhibiting interconnectedness. The primary cluster comprised of plant height, heading time, and 1000-grain weight. Similarly, the second significant cluster contained the varieties with similar grain yield, starch ratio, and the number of spikes m⁻². The varieties ‘Bozlak’ and ‘Mert’, ‘Aydanhanim’ and ‘Tosunpaşa’, ‘Erciyes’ and ‘Çatalhüyük’, and ‘Sabribey’ and ‘Asutay’, exhibited significant resemblance for the recorded traits. The PCA revealed that 1000-grain weight was associated with the heading time, whereas starch ratio was associated with the grain yield. ‘Erciyes’ (3.58 tons ha⁻¹), ‘Çatalhüyük 2001′ (2.95 tons ha⁻¹), and ‘Bozlak’ (2.72 tons ha⁻¹) recorded the highest yield, whereas ‘Erciyes’ variety resulted in the delayed heading. Similarly, ‘Çatalhüyük’, and ‘Erciyes’ produced the highest number of spikes m⁻². Likewise, ‘Çatalhüyük 2001′, and ‘Tosunpaşa’ resulted in the heaviest 1000-grains, while ‘Asutay’ resulted in the highest starch ratio.

Conclusion

It is concluded that ‘Çatalhüyük’, ‘Erciyes’, and ‘Tosunpaşa’ are superior varieties in terms of yield-related traits, whereas ‘Asutay’ proved better for starch ratio. Therefore, these varieties could be used in future breeding programs to improve these traits.