Ordinal regression model for pea seed mass

	Years	April	May	June	July	August
Temperature (°C)	2010	7.5	11.7	16.7	20.4	18.5
	2011	9.7	13.2	17.4	17.3	18.9
	Long-term mean	8.1	13.7	16.5	18.2	17.9
Rainfall (mm)	2010	66.5	193.2	103.5	208.5	95.1
	2011	29.2	71.5	99.5	167.5	73.2
	Long-term mean	50.2	65.3	80.0	74.9	78.5

Table 2

Means and analysis of variance of seed mass and quantitative variables (seeds per pod, pods per plant and seeds per plant) as affected by the qualitative variables (year, cultivar and inoculant)

Tabelle 2. Mittelwerte und Varianzanalyse des Samengewichts und der quantitativen Variablen (Samen pro Hülse, Hülsen pro Pflanze und Samen pro Pflanze) in Abhängigkeit der qualitativen Variablen (Jahr, Sorte und Inokulum)

	Seed mass	Seeds	Pods	Seeds
	(mg)	(per pod)	(per plant)	(per plant)
Year
2010	210^b	2.45^b	6.82^b	28.3^b
2011	270^a	2.88^a	7.18^a	33.5^a
Cultivar
Tarchalska	270^a	2.55^b	6.50^b	27.4^b
Klif	220^b	2.76^a	7.42^a	33.9^a
Inoculant
IUNG	250^a	2.87^a	7.30^a	33.2^a
Nitragina	240^a	2.69^b	6.86^b	30.6^b
Control	260^a	2.45^c	6.85^b	29.1^c

[i] Significant differences are at p < 0.001. Different letters indicate significant differences between means.

No interactions of factors – year, cultivar and inoculant – are shown.

Table 3

Model fitting information

Tabelle 3. Informationen zur Modellanpassung

Model	−2 Log likelihood	Chi-square	df	Significance
Intercept only	10,564.1
Final model	7,338.1	3,226.0	9	0.000

[i] Link function: negative log–log

Table 4

Statistical evaluation of considered factors (ordinal regression model) for seed mass categories

Tabelle 4. Statistische Evaluierung der betrachteten Faktoren (ordinales Regressionsmodelles) hinsichtlich der Kategorien des Samengewichts

Model component	Variable level	Estimate	Standard error	Wald	df	Significance	95% Confidence interval

							Lower bound	Upper bound
Threshold	[1] < 200 mg	−0.824	0.054	232.6	1	<0.001	−0.930	−0.718
	[2] 200–240 mg	−0.303	0.051	35.2	1	<0.001	−0.403	−0.203
	[3] 240–270 mg	0.232	0.052	19.6	1	<0.001	0.129	0.335
	[4] 270–300 mg	1.045	0.059	311.1	1	<0.001	0.929	1.161

Location	[Seeds per pod]	0.056	0.008	50.9	1	<0.001	0.041	0.072
	[Pods per plant]	0.048	0.010	22.2	1	<0.001	0.028	0.068
	[Seeds per plant]	−0.006	0.002	9.7	1	<0.002	−0.010	−0.002
	[Year = 2010]	−0.849	0.030	796.2	1	<0.001	−0.908	−0.790
	[Year = 2011]	0.000	.	.	0	.	.	.
	[Cultivar = Klif]	−0.727	0.028	691. 7	1	<0.001	−0.781	−0.673
	[Cultivar = Tarchalska]	0.000	.	.	0	.	.	.
	[IUNG = 1]	0.081	0.022	13.7	1	<0.001	0.038	0.125
	[Nitragina = 2]	0.038	0.023	2.9	1	0.088	−0.006	0.083
	[Control = 3]	0.000	.	.	0	.	.	.

Scale	[Cultivar = Klif ]	−0.621	0.029	448.2	1	<0.001	−0.678	−0.563
	[Cultivar = Tarchalska]	0.000	.	.	0	.	.	.
	[Year = 2010]	−0.492	0.031	246.6	1	<0.001	−0.553	−0.430
	[Year = 2011]	0.000	.	.	0	.	.	.

[i] Link function: negative log–log

References

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Articles in this issue

DOI: https://doi.org/10.1515/boku-2017-0008 | Journal eISSN: 2719-5430 (formerly 0006-5471) | Journal ISSN: 0006-5471

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Language: English, German

Page range: 81 - 87

Submitted on: Mar 14, 2017

Accepted on: Jul 4, 2017

Published on: Jun 30, 2017

Published by: Universität für Bodenkultur Wien

In partnership with: Paradigm Publishing Services

Publication frequency: Volume open

Keywords:

legume,

Related subjects:

Ecology,

© 2017 Agnieszka Klimek-Kopyra, Jacek Strojny, Tadeusz Zając, Anna Ślizowska, Jana Klimešova, Reinhard W. Neugschwandtner, published by Universität für Bodenkultur Wien
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Volume 68 (2017): Issue 2 (June 2017)