Paper · 2003 · Crop Science

Sequential Path Model for Determining Interrelationships among Grain Yield and Related Characters in Maize

S. A. Mohammadi; B. M. Prasanna; N. N. Singh

8
claims
8
verbatim quotes
204
citations
2
research areas
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Not open access

Abstract

Knowledge of interrelationships between grain yield and its contributing components will improve the efficiency of breeding programs through the use of appropriate selection indices. Previous path analyses studies in maize ( Zea mays L.) treated yield components as first‐order variables. The present study, based on evaluation of 90 experimental maize hybrids (comprising one diallel and one line × tester set) at two locations in India, utilizes a sequential path model for analysis of genetic associations among grain yield and its related traits by ordering the various variables in first‐, second‐, and third‐order paths on the basis of their maximum direct effects and minimal collinearity. The sequential path model showed distinct advantages over the conventional path model in discerning the actual effects of different predictor variables. Two first‐order variables, namely 100‐grain weight and total number of kernels per ear, revealed highest direct effects on total grain weight ( p = 0.74 and p = 0.78, respectively), while ear length, ear diameter, number of kernel rows, and number of kernels per row were found to fit as second‐order variables. All direct effects were found to be significant, as indicated by bootstrap analysis. Test for the goodness‐of‐fit revealed that the sequential path model provided better fit to various datasets analyzed in the study. Correlations between the predicted values of various response variables in the second season dataset based on the path coefficients of the first season were high, except for ear length and number of kernels per row. The applicability of the model has been confirmed through analysis of two additional datasets during 2000. The results indicated the utility of the sequential path model for determining the interrelationships among grain yield and related traits in maize.

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Claims 8

Method / resourceobservedoriginal resultpositivemeasured

Claim · model-written summary

The sequential path model better discerned predictor effects than the conventional path model.

Outcome
discerning the actual effects of different predictor variablese0
Direction
distinct advantagese0
Comparator
conventional path modele0

Verbatim

e0

“sequential path model showed distinct advantages over the conventional path model in discerning the actual effects of different predictor variables”

✓ located verbatim in the source · abstract, characters 701–848 · show in text ↑
Associationobservedoriginal resultpositivesignificant (as stated)measured

Claim · model-written summary

100-grain weight had a high direct effect on total grain weight, p = 0.74.

Organ / stage
100‐grain weighte0
Outcome
total grain weighte0
Direction
highest direct effectse0
Value
p = 0.74e0

Not reportedTaxon

Verbatim

e0

“100‐grain weight and total number of kernels per ear, revealed highest direct effects on total grain weight ( p = 0.74 and p = 0.78, respectively)”

✓ located verbatim in the source · abstract, characters 884–1030 · show in text ↑
Associationobservedoriginal resultpositivesignificant (as stated)measured

Claim · model-written summary

Total kernels per ear had a high direct effect on total grain weight, p = 0.78.

Organ / stage
total number of kernels per eare0
Outcome
total grain weighte0
Direction
highest direct effectse0
Value
p = 0.78e0

Not reportedTaxon

Verbatim

e0

“100‐grain weight and total number of kernels per ear, revealed highest direct effects on total grain weight ( p = 0.74 and p = 0.78, respectively)”

✓ located verbatim in the source · abstract, characters 884–1030 · show in text ↑
Method / resourceobservedoriginal resultmeasured

Claim · model-written summary

Ear length, ear diameter, kernel row number and kernels per row fit as second-order variables.

Outcome
second‐order variablese0

Not reportedComparatorValue

Verbatim

e0

“ear length, ear diameter, number of kernel rows, and number of kernels per row were found to fit as second‐order variables”

✓ located verbatim in the source · abstract, characters 1038–1160 · show in text ↑
Observationobservedoriginal resultsignificant (as stated)measured

Claim · model-written summary

All direct effects were significant in bootstrap analysis.

Outcome
direct effectse0

Not reportedTaxonDirection

Verbatim

e0

“All direct effects were found to be significant, as indicated by bootstrap analysis”

✓ located verbatim in the source · abstract, characters 1162–1245 · show in text ↑
Method / resourceobservedoriginal resultpositivemeasured

Claim · model-written summary

Sequential path model fit was better across the analyzed datasets.

Outcome
fite0
Direction
bettere0
Comparator
various datasetse0

Verbatim

e0

“sequential path model provided better fit to various datasets analyzed in the study”

✓ located verbatim in the source · abstract, characters 1294–1377 · show in text ↑
Observationobservedoriginal resultpositivemeasured

Claim · model-written summary

Predicted-response correlations between seasons were high except for ear length and kernels per row.

Outcome
Correlations between the predicted values of various response variablese0
Direction
highe0
Qualifier
except for ear length and number of kernels per rowe0

Not reportedTaxon

Verbatim

e0

“Correlations between the predicted values of various response variables in the second season dataset based on the path coefficients of the first season were high, except for ear length and number of kernels per row”

✓ located verbatim in the source · abstract, characters 1379–1593 · show in text ↑
Method / resourceobservedoriginal resultpositivemeasured

Claim · model-written summary

The model was applicable to two additional datasets analyzed in 2000.

Outcome
applicability of the modele0
Value
two additional datasetse0

Verbatim

e0

“applicability of the model has been confirmed through analysis of two additional datasets during 2000”

✓ located verbatim in the source · abstract, characters 1599–1700 · show in text ↑