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Agronomic research results include Type 1 (a) and Type 2 (b) errors. Results are often reported using α ≤0.05 while b is ignored. Our objective was to discuss whether a false positive was more serious than a false negative in agronomic research. For comparison, current statistical methods used in Agronomy Journal were tabulated. Most papers used null hypothesis tests with a ≤0.05, reporting results based on the LSD among all treatment pairs. Current practices do not account for the relative costs of false positive vs. false negative errors. A case study from the Washington State Wheat Extension trials was analyzed using mixed models with specific contrasts. While the overall effect for cultivar was significant, the β error rate for the contrast was 40% and additional replications were needed to increase the power of this contrast. A second case study analyzed trials evaluating wheat (Triticum aestivum L.) resistance to Fusarium crown rot. Optimal α and β error rates were estimated for two to eight replications with the Type1/Type2 error cost ratio set at 1:1 and 1:5. An average error rate (α and β) ≤0.05 could be achieved with four replications when a reduction in the β error was critical and α errors could be corrected in future experiments. Effective experimental design requires estimation of the acceptable magnitude and cost ratio of false positive and false negative errors and critical effect sizes. To be truly informative, reports of results should include this information plus observed effect sizes and variances. [ABSTRACT FROM AUTHOR]

Variability in yield among sugarcane (a complex hybrid of Saccharum spp.) genotypes grown with and without mill mud application on sand soils in Florida has been documented, but little is known about what causes yield differences and if there are any relationships between yield components and physiological parameters. This study determined responses of leaf relative chlorophyll level (SPAD readings), photochemical efficiency of photosystem II in dark-adapted leaves (Fv/Fm), leaf stomatal conductance (gs), net photosynthetic rate (Pn), transpiration rate (E), difference between leaf and air temperatures (Tl-Ta), and spectral reflectance in one Erianthus [Erianthus arundinaceus (Rez.) Jeswiet] and seven sugarcane genotypes and their relationships to yield components across genotypes. Reflectance, Fv/Fm, SPAD, gs, Pn, E, and Tl-Ta were measured on leaves at the top visible dewlap during the first- and second-ratoon crops on a Margate sand soil (siliceous, hyperthermic Mollic Psammaquent) with or without mill mud added before planting. Mill mud application reduced leaf reflectance at wavelengths of 560 and 710 nm and significantly increased leaf SPAD, gs, Pn, and E in the first-ratoon crop only. Genotypic differences were detected in most physiological traits and yield components. Most physiological traits correlated with cane and sucrose yields when no mill mud was added. Genotypic variation in physiological and yield responses to mill mud application and genotype x mill mud interactions in yields indicated that augmenting yield selection of genotypes with leaf physiological traits will improve sugarcane breeding programs for sand soils. [ABSTRACT FROM AUTHOR]