02173naa a2200265 a 450000100080000000500110000800800410001910000190006024500810007926000090016050001310016952013140030065000130161465000150162765000230164265300200166565300260168565300140171165300160172570000210174170000180176270000180178070000200179877300890181811102792018-08-27       2004    bl uuuu     u00u1 u    #d1 aARAÚJO, A. P.  aSample size for measurement of root traits on common bean by image analysis.  c2004  aTítulo em português: Tamanho da amostra para determinação de caracteres radiculares do feijoeiro pela análise de imagens.  aEvaluation of root traits may be facilitated if they are assessed on samples of the root system. The objective of this work was to determine the sample size of the root system in order to estimate root traits of common bean (Phaseolus vulgaris L.) cultivars by digital image analysis. One plant was grown per pot and harvested at pod setting, with 64 and 16 pots corresponding to two and four cultivars in the first and second experiments, respectively. Root samples were scanned up to the completeness of the root system and the root area and length were estimated. Scanning a root sample demanded 21 minutes, and scanning the entire root system demanded 4 hours and 53 minutes. In the first experiment, root area and length estimated with two samples showed, respectively, a correlation of 0.977 and 0.860, with these traits measured in the entire root. In the second experiment, the correlation was 0.889 and 0.915. The increase in the correlation with more than two samples was negligible. The two samples corresponded to 13.4% and 16.9% of total root mass (excluding taproot and nodules) in the first and second experiments. Taproot stands for a high proportion of root mass and must be deducted on root trait estimations. Samples with nearly 15% of total root mass produce reliable root trait estimates.  asampling  aAmostragem  aPhaseolus Vulgaris  aárea radicular  acomprimento radicular  aroot area  aroot length1 aFERNANDES, A. M.1 aKUBOTA, F. Y.1 aBRASIL, F. C.1 aTEIXEIRA, M. G.  tPesquisa Agropecuária Brasileira, Brasília, DFgv. 39, n. 4, p. 313-318, abr. 2004