Sample Size to Estimate the Mean and Median of Traits in Canola

Alberto Cargnelutti Filho,Cleiton Antonio Wartha,Daniela Lixinski Silveira,Ismael Mario Marcio Neu,Jéssica Andiara Kleinpaul

doi:10.5539/jas.v10n11p123

Alberto Cargnelutti Filho, Cleiton Antonio Wartha + Show 3 more

Open Access

https://doi.org/10.5539/jas.v10n11p123

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Abstract

The aim of this study was to determine the sample size (i.e., number of plants) required to estimate the mean and median of canola (Brassica napus L.) traits of the Hyola 61, Hyola 76, and Hyola 433 hybrids with precision levels. At 124 days after sowing, 225 plants of each hybrid were randomly collected. In each plant, morphological (plant height) and productive traits (number of siliques, fresh matter of siliques, fresh matter of aerial part without siliques, fresh matter of aerial part, dry matter of siliques, dry matter of aerial part without siliques, and dry matter of aerial part) were measured. For each trait, measures of central tendency, variability, skewness, and kurtosis were calculated. Sample size was determined by resampling with replacement of 10,000 resamples. The sample size required for the estimation of measures of central tendency (mean and median) varies between traits and hybrids. Productive traits required larger sample sizes in relation to the morphological traits. Larger sample sizes are required for the hybrids Hyola 433, Hyola 61, and Hyola 76, in this sequence. In order to estimate the mean of canola traits of the Hyola 61, Hyola 76 e Hyola 433 hybrids with the amplitude of the confidence interval of 95% equal to 30% of the estimated mean, 208 plants are required. Whereas 661 plants are necessary to estimate the median with the same precision.

Highlights

Canola (Brassica napus L.) belongs to the Brassicaceae family (Tomm, Wiethölter, Dalmago, & Santos, 2009)
Three uniformity trials were carried out with canola (Brassica napus L.) in experimental area of 45 m × 60 m (2,700 m2) in southern Brazil, located at 29o42′S, 53o49′W, with 95 m altitude
The mean of the plant height (PH), NS, fresh matter of siliques (FMS), fresh matter of aerial part without siliques (FMWS), FM, dry matter of siliques (DMS), dry matter of aerial part without siliques (DMWS), and DM traits was greater in the Hyola 76 hybrid, intermediate in Hyola 433, and smaller in Hyola 61, which demonstrates superior agronomic performance of Hyola 76 hybrid (Table 1)

Summary

Introduction

Canola (Brassica napus L.) belongs to the Brassicaceae family (Tomm, Wiethölter, Dalmago, & Santos, 2009). Canola seeds are utilized as edible oil for human consumption, livestock feed and biofuel feedstock, being the second most prominent oil seed crop in the world (Li et al, 2015). In Brazil, canola is used for grain production during winter cool-season in crop rotation systems. Canola can act controlling root diseases in annual crops by mechanisms of biofumigation and absence of host (Angus et al, 2015). Other synergistic effects on total system yield can be observed, such as weed growth suppression and flexibility in chemical weed control options. Besides grain yield and oil content, sample dimensioning of dry matter traits is relevant to assess its cover crop potential

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