Wheat grain width: a clue for re-exploring visual indicators of grain weight

Table 4 The coefficients of correlation (R) among the basic shape factors and the three superior synthetized indices used for mean grain weight prediction

Parameters	Major	Minor	Area	Ellipse area	Perim	Area/Perim	Area × Circ
Minor	0.608
Area	0.849	0.932
Ellipse area	0.849	0.932	1
Perim	0.959	0.801	0.958	0.958
Area/Perim	0.719	0.987	0.973	0.973	0.875
Area × Circ	0.717	0.984	0.975	0.975	0.873	0.997
Perim. × Circ	0.719	0.987	0.973	0.973	0.875	1	0.997

In this analysis, data of 19,596 grains sampled from the monocultures of 4 early- to middle-ripening cultivars was used (enhanced-resolution images were processed).
All correlations were very significant (P < 0.0001).
The bolded values show the superior correlation of basic shape factors (i.e. Major, Minor, Area, Ellipse area, or Perimeter) in each row.
"Ellipse area" is the area of the best ellipse fitted on the grain, and calculated as follows (in the present evaluation, the difference between Area and Ellipse area was almost zero, i.e. in average less than % 2.3 × 10^–8): \({Ellipse\, area}=(Major/2)\times (Minor/2)\times \pi\)

ISSN: 1746-4811