Which common bean root phenotyping method is best? This depends on the phenological growth stage

To assess the impact of different phenotyping methods and crop phenological stages on the differentiation of parent versus progeny performance for root traits in common bean breeding programs, a field experiment was carried out in the 2021/22 growing season. In a lattice design, 36 field treatments were tested, based on three genotypes and two root phenotyping methods (Shovelomics and WinRHIZO) applied at six phenological stages (V4-4; V4-8; R5; R6; R7 and R8). Eight response variables of the root system were evaluated. The Shovelomics method significantly influenced parent-progeny distinction at the V4-4 (vegetative) and the WinRHIZO method at the R8 (reproductive) stage. Mean heritability estimates of 0.35 and 0.30 were calculated. As the heritability values were moderate to low, it is worth emphasizing that root phenotyping can be performed in more advanced inbreeding generations, due to the strong environmental influence on root trait expression.