Abstract
Summary Several alternative statistical approaches to the analysis of genotype-environment interactions are summarized, and their inter-relationships are presented mathematically and graphically. An experiment was designed to test the ability of these analyses to satisfactorily describe genotype-environment interactions and to locate genotypes causing or contributing significantly to such interactions in a situation where environments differed in only one factor, i.e. soil nitrogen status. Twenty-five lines of wheat were grown at each of 5 levels of applied nitrogen (0–270 kg N/ha) in a sandy, nitrogen-deficient soil, and their grain yields and yield components (ears per unit area, grains per ear, weight per grain) were determined. Designating the nitrogen levels as ‘environments’, linear yield responses, and deviations from linear responses, of individual wheat entries to environment mean yield were calculated according to the various statistical procedures previously outlined. The results suggested that the linear response to environment mean yield was similar for all wheat entries. However, further inspection of the data revealed that the responses of eight entries to environment mean yield departed significantly from linearity. Although several analyses satisfactorily identified these aberrant entries, classifying them as ‘unstable’, it was concluded that the degree of departure from linearity of response was not an adequate measure of instability. Furthermore, as previously suggested by Knight (1970), it was confirmed that the relative ranking of an entry for yield stability according to such a concept varied according to the average response of the group of entries with which it was being compared. The general effects of applied nitrogen on yield components were to increase the number of ears and the number of grains per ear, and to decrease grain weight. However, only the first of these effects occurred consistently for all entries. The number and weight of individual grains per ear varied with the nitrogen treatment, often unpredictably, in a complex pattern which differed significantly between entries.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 9
Claim · model-written summary
Linear yield response to environment mean yield was similar across wheat entries.
- Taxon
- wheat
Triticum aestivume0 - Outcome
- linear response to environment mean yielde0
- Direction
- similare0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the linear response to environment mean yield was similar for all wheat entries”
Claim · model-written summary
Eight wheat entries showed significant departure from linear response to environment mean yield.
- Taxon
- wheatTriticum aestivume1
- Outcome
- responses of eight entries to environment mean yield departed significantly from linearitye0
- Value
- eight entriese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“responses of eight entries to environment mean yield departed significantly from linearity”
e1“similar for all wheat entries”
Claim · model-written summary
Several analyses identified the aberrant wheat entries as unstable.
- Taxon
- wheatTriticum aestivume1
- Outcome
- identified these aberrant entriese0
- Comparator
- ‘unstable’e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“several analyses satisfactorily identified these aberrant entries, classifying them as ‘unstable’”
e1“similar for all wheat entries”
Claim · model-written summary
Departure from linearity was judged inadequate for measuring wheat yield instability.
- Taxon
- wheatTriticum aestivume1
- Outcome
- measure of instabilitye0
- Comparator
- degree of departure from linearity of responsee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the degree of departure from linearity of response was not an adequate measure of instability”
e1“similar for all wheat entries”
Claim · model-written summary
A wheat entry’s yield stability ranking varied with the average response of the comparison group.
- Taxon
- wheatTriticum aestivume1
- Outcome
- relative ranking of an entry for yield stabilitye0
- Comparator
- average response of the group of entriese0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the relative ranking of an entry for yield stability according to such a concept varied according to the average response of the group of entries with which it was being compared”
e1“similar for all wheat entries”
Claim · model-written summary
Applied nitrogen generally increased wheat grains per ear.
- Taxon
- wheatTriticum aestivume1
- Treatment
- applied nitrogene0
- Outcome
- number of grains per eare0
- Direction
- increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The general effects of applied nitrogen on yield components were to increase the number of ears and the number of grains per ear, and to decrease grain weight.”
e1“similar for all wheat entries”
Claim · model-written summary
Applied nitrogen generally decreased wheat grain weight.
- Taxon
- wheatTriticum aestivume1
- Treatment
- applied nitrogene0
- Outcome
- grain weighte0
- Direction
- decreasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The general effects of applied nitrogen on yield components were to increase the number of ears and the number of grains per ear, and to decrease grain weight.”
e1“similar for all wheat entries”
Claim · model-written summary
Grain number per ear varied unpredictably with nitrogen treatment and differed significantly among wheat entries.
- Taxon
- wheatTriticum aestivume1
- Treatment
- nitrogen treatmente0
- Outcome
- number and weight of individual grains per eare0
- Qualifier
- often unpredictablye0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The number and weight of individual grains per ear varied with the nitrogen treatment, often unpredictably, in a complex pattern which differed significantly between entries.”
e1“similar for all wheat entries”
Claim · model-written summary
Grain weight varied unpredictably with nitrogen treatment and differed significantly among wheat entries.
- Taxon
- wheatTriticum aestivume1
- Treatment
- nitrogen treatmente0
- Outcome
- weight of individual grains per eare0
- Qualifier
- often unpredictablye0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The number and weight of individual grains per ear varied with the nitrogen treatment, often unpredictably, in a complex pattern which differed significantly between entries.”
e1“similar for all wheat entries”
The same questions in other papers
nitrogen · yield · Triticum aestivum (wheat)Positive and negative results
1,736 papers in the same direction as this paper · 285 in the opposite direction · 39 reporting no difference from an alternative
- negative
- negative
- negative
2,057 papers more in this group
See all 2,061 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.