A Low cost and high throughput spectroscopic method for quantification of seed coat colour differences in plain seeded bean (Phaseolus vulgaris L.) germplasm from Western Himalayan Kashmir

Abstract

Seed phenotyping is routinely done using visual assessment that suffers from subjectivity. In the present study we phenotyped 278 Western Himalayan bean accessions using a low cost spectroscopic method based on quantification of seed colour in terms of L*,a*,b* and δ E. There was substantial variation for L*, a*, b* and δ E parameters for all seven colour classes. The mean value for L* was lowest for red (31.31) and highest for white (78.17) and reverse in case of a*. Similarly, mean value for b* was lowest for black (-0.29) and highest for yellow (40.86). In terms of deviations from standard colours depicted by δ E, highest mean value was observed in red colour (6012.16) and lowest was recorded for green (18.36) with a mean of 2525.72 across all colours. The first two principal components accounted for 86.74% of variation. contributed by colour and L* in PC1 and b*, L* and a* in PC2. In the present study, based on the factor loading graph, colour is strongly correlated with L* as is evident from its significant contribution in both PC1 and PC2. The multivariate analysis clearly delineates the diversity panel of 278 genotypes into distinct colour groups as shown by concentration of genotypes of similar colour class into specific regions of four coordinates of biplot based on L*, a* and b* values and their observed relationship with colour scores. The method removes the subjectivity in visual colour specifications, is quantitative and can help in exact quantification of varietal differences.

Plant phenotyping relevance

種子表面色という植物形質を、主観的な目視評価に代わる低コスト・高スループット分光法で定量化することが研究の中心であり、方法開発と大規模適用に該当する。

Code and data availability

The preprint describes L*a*b*/δE colorimetric phenotyping of 278 bean accessions but contains no data availability statement, no public phenotype dataset, no seed images, and no author code or model deposit. The only URLs present are references (CIE report, cited papers), which are not paper-specific assets.

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