Abstract
We obtained full‐sib and half‐sib covariances in two open‐pollinated varieties of maize, ‘Jarvis’ and ‘Indian Chief,’ from families derived from both inbred and noninbred parents. These covariances provide estimates of additive, dominance, and certain estimable functions of epistatic variances, and are useful to investigate the relative importance of the different types of genetic variation in these varieties. Seven characters were studied in both varieties, and no evidence of epistatic variance was noted except possibly for yield in Indian Chief. During development of the random inbred lines natural selection increased ear number and yield in both varieties. It may also have reduced the total genetic variance for characters that showed no change in the mean. Both the observed and “expected” standard errors were smaller for estimates of variance components obtained from the Design II than from the Design I experiments. Observed standard errors of the experimental error variances were larger than “expected standard errors” for both Designs. Additive variance appeared to account for the largest proportion of the total genetic variance for all characters in both varieties. Hence, recurrent selection should be effective in improving these varieties.
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Claims 7
Claim · model-written summary
No epistatic variance was found across seven characters except possibly yield in Indian Chief.
- Material
- Indian Chiefe0
- Outcome
- epistatic variancee0
- Qualifier
- except possibly for yield in Indian Chiefe0
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“no evidence of epistatic variance was noted except possibly for yield in Indian Chief.”
t0“Maize”
Claim · model-written summary
Natural selection during inbred line development increased ear number and yield in both varieties.
- Material
- both varietiese0
- Treatment
- natural selectione0
- Outcome
- ear number and yielde0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“During development of the random inbred lines natural selection increased ear number and yield in both varieties.”
t0“Maize”
Claim · model-written summary
Natural selection may have reduced total genetic variance for characters with unchanged means.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“It may also have reduced the total genetic variance for characters that showed no change in the mean.”
t0“Maize”
t1“natural selection increased ear number and yield in both varieties.”
Claim · model-written summary
Design II yielded smaller observed and expected standard errors for variance component estimates than Design I.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Both the observed and “expected” standard errors were smaller for estimates of variance components obtained from the Design II than from the Design I experiments.”
t0“Maize”
Claim · model-written summary
Observed error variance standard errors exceeded expected standard errors in both designs.
- Outcome
- Observed standard errors of the experimental error variancese0
- Direction
- largere0
- Comparator
- “expected standard errors”e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Observed standard errors of the experimental error variances were larger than “expected standard errors” for both Designs.”
t0“Maize”
Claim · model-written summary
Additive variance appeared to contribute the largest share of total genetic variance for all characters in both varieties.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Additive variance appeared to account for the largest proportion of the total genetic variance for all characters in both varieties.”
t0“Maize”
Claim · model-written summary
Recurrent selection should improve these varieties.
- Outcome
- recurrent selection should be effective in improving these varietiese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“recurrent selection should be effective in improving these varieties.”
t0“Maize”