Optimum allocation of plots to years, seasons, locations, and replications, and its application to once-over-harvest cucumber trials

Swallow, William H.; Wehner, Todd C.

doi:10.1007/bf00037897

Cited by 21 publications

(14 citation statements)

References 15 publications

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“…Cullis et al (2000) and Laidig et al (2008) reported estimated genotypic, environmental, and genotype-by-environment interaction variability for common crops in Australia and Germany, respectively. Swallow and Wehner (1989) and Brennan et al (1998) considered optimal designs for series of breeding trials, taking financial costs into account. Cullis et al (2000) discussed the accuracy of alternative schemes, with different numbers of replicates, locations, and years.…”

Section: Introductionmentioning

confidence: 99%

Effect of region on the uncertainty in crop variety trial programs with a reduced number of trials

2012

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Results from crop variety trials may vary between geographical regions because of differences in climate and soil types. Results are usually presented at regional level. To evaluate the importance of the regions used in the Swedish variety trial programs, we examined which regions produced similar levels of yield and similar ratios in yield between cultivars; the amount by which variance could be reduced by division into regions or clusters of regions; and the amount of trials per region and year, replicates per trial, and trials per year required in order to fulfill specifications on the precision of results. Yield data from spring barley and winter wheat trials performed during 1997-2006 were studied using cluster analysis and variance component estimation. The objectives were (1) to discuss the effects of regions on precision when the number of trials has decreased; (2) to demonstrate the method; and (3) to report the results obtained. In spring barley, clusters of regions produced different levels of yield, but similar yield ratios between cultivars. In winter wheat, clusters of regions giving different yield ratios were identified. When the option of a single analysis was compared with that of region-wise analysis, the reduction in variance with the former, due to the larger number of trials, outweighed the reduction in variance with the latter due to decreased random interaction between trials and cultivars.

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Section: Introductionmentioning

confidence: 99%

Effect of region on the uncertainty in crop variety trial programs with a reduced number of trials

2012

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“…In cucumber, small-plot, single-harvest trials were more efficient than large-plot, multiple-harvest trials (Wehner, 1986(Wehner, , 1989Wehner and Miller, 1987). Swallow and Wehner (1989) suggested that maximum information (1/variance) was obtained by allocating test plots of cucumber cultigens over different seasons and years rather than different locations and replications. However, use of locations and replications was less expensive than use of seasons and years.…”

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Screening the Cucumber Germplasm Collection for Combining Ability for Yield

Wehner¹,

Shetty²,

Clark³

2000

HortSci

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Cucumber (Cucumis sativus L.) plant introduction (PI) accessions from the regional PI station at Ames, Iowa were evaluated in open-field production for single-harvest yield at Clinton, N.C. and Ames, Iowa. Check cultivars and experimental inbreds were also tested for comparison with the PI accessions (the three groups hereafter collectively referred to as cultigens). In order to make the evaluation more uniform for all cultigens regardless of sex expression and fruit size, all were crossed with Gy 14, a gynoecious pickling cucumber inbred used commonly in the production of commercial hybrids. The resulting 761 gynoecious hybrids were tested for early, total, and marketable yield using recommended cultural practices. Results were obtained for 725 cultigens at both locations. Significant differences were observed among cultigens for all traits evaluated. Differences between the two locations were also significant for total yield, corrected total yield, and percentage of early fruit. The interaction of cultigen and location was significant for standardized total yield and standardized corrected total yield. The highest yielding hybrids at both locations were produced using the following cultigens as male (paternal) parents: PI 422185, PI 390253, PI 175120, PI 173889, PI 267087, PI 175686, PI 178888, PI 385967, PI 458851, and PI 171601. The highest and lowest yielding paternal parents from the germplasm screening study were retested, along with check cultigens in a multiple-harvest trial at Clinton, N.C. Cultigens were evaluated directly, rather than as hybrids with Gy 14, and fruit number, fruit weight, and sex expression were recorded. Most cultigens performed as expected for the yield traits in the retest study. The exceptions were `Wautoma' and PI 339250, which were among the low and high yielders in the first test, but were ranked as medium and low, respectively, in the retest study.

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“…Reports on crops other than fruit (Kaltsikes, 1970;Mycroft, 1983;Patterson et al, 1977;Rasmussen and Lambert, 1961;Sekioka and Lauer, 1970;Shorter and Norman, 1983;Swallow and Wehner, 1989) indicated that adding more locations, years, or both was more efficient than adding replications.…”

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confidence: 99%

Optimal Spatial and Temporal Measurement Repetition for Selection in Japanese Persimmon Breeding

Yamada¹,

Yamane²,

Yoshinaga³

et al. 1993

HortSci

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Genetic and environmental variances for fruit ripening time (FRT), fruit weight, and soluble solids concentration (SSC) in Japanese persimmon (Diospyros kaki Thunb.) were estimated. The variance among fruit within a tree was the largest among environmental variances. Therefore, using a large sample size per tree and per year effectively increased heritability, but the effect was minimal when more than five fruit were sampled. The variance among years was largest for SSC and smallest for FRT. Generally, the variance associated with the genotype × year interaction was as large as the tree × year interaction. The variance among trees within a genotype was negligible for all traits. Repeating measurements yearly was more efficient than replicating trees.

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Optimum allocation of plots to years, seasons, locations, and replications, and its application to once-over-harvest cucumber trials

Cited by 21 publications

References 15 publications

Effect of region on the uncertainty in crop variety trial programs with a reduced number of trials

Effect of region on the uncertainty in crop variety trial programs with a reduced number of trials

Screening the Cucumber Germplasm Collection for Combining Ability for Yield

Optimal Spatial and Temporal Measurement Repetition for Selection in Japanese Persimmon Breeding

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