Abstract
Systematic genetic advance in maize ( Zea mays L.) hybrid yields depends on the improvement of breeding populations and the efficient extraction of inbred lines. We evaluated the efficacy of selection among and within fullsib families produced in two 2‐eared populations for the extraction of lines and for the identification of superior yielding hybrids. Intra‐ and interpopulation crosses were made among selected and unselected lines developed from ‘Iowa Two‐ear Synthetic’ (BSI0) and ‘Pioneer Prolific Composite’ (BSll). The selected lines were superior paired‐plant interpopulation crosses tested from the S 0 ✕ S 0 through S 4 ✕ S 4 generations. Six sets, each containing 28 crosses, produced from selected and unselected lines, were grown in three locations for 3 years. Interpopulation crosses averaged 5.8 quintals/ha (7.4%)greater yields than intrapopulation crosses, and the crosses of selected lines yielded 8.7 quintals/ha (11.2%) more than crosses of unselected lines. On the average, the tested paired‐plant crosses yielded 3.7 quintals/ha (4.2%) more than the untested crosses among selected lines and the specific combining ability (SCA) effects tended to be strongly positive for the tested line pairs. The yields of the previously untested crosses among the selected lines also showed that the selected lines expressed high general combining ability (GCA) with other selected lines. If the five best single‐crosses from each set were selected (9% selection intensity), 28 of 30 were from interpopulation crosses, 23 of 28 from selected lines, and II of 23 from the tested‐line pairs. If only the selected interpopulation crosses were grown (96 entries), 23 of the best 30 hybrids were identified from 336 entries. The method of selection, therefore, does develop an elite group of lines having high SCA with its tested mate and also high GCA with other elite lines with a minimum of testing. Thus selection among and within full‐sib families seems to be an efficient method of developing superior parental lines for hybrids.
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 10
Claim · model-written summary
Interpopulation crosses yielded more than intrapopulation crosses.
- Material
- Interpopulation crossese0
- Outcome
- yieldse0
- Direction
- greatere0
- Value
- 5.8 quintals/hae0
- Comparator
- intrapopulation crossese0
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Interpopulation crosses averaged 5.8 quintals/ha (7.4%)greater yields than intrapopulation crosses”
t0“Maize”
Claim · model-written summary
Selected-line crosses yielded more than unselected-line crosses.
- Material
- crosses of selected linese0
- Outcome
- yieldede0
- Direction
- moree0
- Value
- 8.7 quintals/hae0
- Comparator
- crosses of unselected linese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“crosses of selected lines yielded 8.7 quintals/ha (11.2%) more than crosses of unselected lines”
t0“Maize”
Claim · model-written summary
Tested paired-plant crosses yielded more than untested selected-line crosses.
- Material
- tested paired‐plant crossese0
- Outcome
- yieldede0
- Direction
- moree0
- Value
- 3.7 quintals/hae0
- Comparator
- untested crosses among selected linese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tested paired‐plant crosses yielded 3.7 quintals/ha (4.2%) more than the untested crosses among selected lines”
t0“Maize”
Claim · model-written summary
Tested line pairs tended toward positive specific combining ability.
- Material
- tested line pairse0
- Outcome
- specific combining ability (SCA) effectse0
- Direction
- strongly positivee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“specific combining ability (SCA) effects tended to be strongly positive for the tested line pairs”
t0“Maize”
Claim · model-written summary
Selected lines showed high general combining ability with other selected lines.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“selected lines expressed high general combining ability (GCA) with other selected lines”
t0“Maize”
Claim · model-written summary
Of 30 best crosses, 28 were interpopulation crosses.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“28 of 30 were from interpopulation crosses”
t0“Maize”
Claim · model-written summary
Of 28 best interpopulation crosses, 23 came from selected lines.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“23 of 28 from selected lines”
t0“Maize”
Claim · model-written summary
Of 23 selected-line best crosses, 11 were tested pairs.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“II of 23 from the tested‐line pairs”
t0“Maize”
Claim · model-written summary
Selecting interpopulation crosses identified 23 of the top 30 from 336 entries.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“23 of the best 30 hybrids were identified from 336 entries”
t0“Maize”
Claim · model-written summary
The selection method developed elite lines with high SCA and GCA with limited testing.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“method of selection, therefore, does develop an elite group of lines having high SCA with its tested mate and also high GCA with other elite lines with a minimum of testing”
t0“Maize”