Abstract
The extent to which time to flowering of a Brassica napus commercial cultivar could be reduced through utilization of genes in its primary and secondary pools was examined with particular reference to yield improvement in lower rainfall environments. The B. napus breeding line RU2 and the B. campestris population Chinoli C42, which were used as sources of early flowering genes to be incorporated into the commercial B. napus cultivar Wesbrook, flowered significantly earlier than Wesbrook with or without vernalization and/or long days. In the cross of Wesbrook with RU2, the substantial variation in flowering time in the F2 was highly heritable (hn2 = 0.79), and some plants in the F2 and first backcross to Wesbrook flowered earlier than the early flowering parent RU2. Many lines flowering much earlier than Wesbrook were still obtained after two generations of recurrent backcrossing to Wesbrook and subsequent selfing without selection at any stage. Variation in flowering time among these lines primarily reflected differences in growth rate as measured by the rate of leaf node development. F2 plants derived from the cross between Wesbrook and the B. campestris population Chinoli C42 varied widely in chromosome number and flowering time, but there was no relationship between pre-anthesis development and chromosome number. Two generations of recurrent backcrossing to Wesbrook and subsequent selfing without selection at any stage produced a series of lines all having the normal B. napus chromosome complement. All these lines flowered significantly earlier than Wesbrook, and the earliest flowering line flowered at the same time as the early flowering B. campestris parent. The implications of these results are discussed with particular reference to developing agronomically superior B. napus cultivars closely adapted to lower rainfall environments in the Western Australian wheatbelt and elsewhere in southern Australia.
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Claims 10
Claim · model-written summary
RU2 flowered significantly earlier than Wesbrook with or without vernalization and long days.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Brassica_napus_-_Habit.jpg?width=500)
Verbatim
e0“The B. napus breeding line RU2 and the B. campestris population Chinoli C42, which were used as sources of early flowering genes to be incorporated into the commercial B. napus cultivar Wesbrook, flowered significantly earlier than Wesbrook with or without vernalization and/or long days”
Claim · model-written summary
Chinoli C42 flowered significantly earlier than Wesbrook.
- Taxon
- B. campestris
.jpg?width=60)
Brassica rapa subsp. oleiferae0 - Material
- Chinoli C42e0
- Outcome
- flowerede0
- Direction
- earliere0
- Comparator
- Wesbrooke0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“The B. napus breeding line RU2 and the B. campestris population Chinoli C42, which were used as sources of early flowering genes to be incorporated into the commercial B. napus cultivar Wesbrook, flowered significantly earlier than Wesbrook with or without vernalization and/or long days”
Claim · model-written summary
Flowering time variation in the Wesbrook by RU2 F2 was highly heritable.
Not reportedTaxonDirection
Verbatim
e0“the substantial variation in flowering time in the F2 was highly heritable (hn2 = 0.79)”
Claim · model-written summary
Some F2 and first backcross plants flowered earlier than RU2.
Not reportedTaxon
Verbatim
e0“some plants in the F2 and first backcross to Wesbrook flowered earlier than the early flowering parent RU2”
Claim · model-written summary
Early flowering lines remained after two backcrosses and selfing without selection.
Not reportedTaxon
Verbatim
e0“Many lines flowering much earlier than Wesbrook were still obtained after two generations of recurrent backcrossing to Wesbrook and subsequent selfing without selection at any stage”
Claim · model-written summary
Flowering-time variation among lines primarily reflected leaf node development rate.
Not reportedTaxonDirection
Verbatim
e0“Variation in flowering time among these lines primarily reflected differences in growth rate as measured by the rate of leaf node development”
Claim · model-written summary
Flowering time and chromosome number were unrelated in Wesbrook by Chinoli C42 F2 plants.
- Taxon
- B. campestrisBrassica rapa subsp. oleiferae0
- Material
- F2 plantse0
- Outcome
- pre-anthesis developmente0
- Qualifier
- no relationship between pre-anthesis development and chromosome numbere0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“F2 plants derived from the cross between Wesbrook and the B. campestris population Chinoli C42 varied widely in chromosome number and flowering time, but there was no relationship between pre-anthesis development and chromosome number”
Claim · model-written summary
Backcrossing and selfing produced lines with the normal B. napus chromosome complement.
- Taxon
- B. napus
_Brassica_napus_-_Habit.jpg?width=60)
Brassica napuse0 - Material
- linese0
- Outcome
- normal B. napus chromosome complemente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Two generations of recurrent backcrossing to Wesbrook and subsequent selfing without selection at any stage produced a series of lines all having the normal B. napus chromosome complement”
Claim · model-written summary
All resulting lines flowered significantly earlier than Wesbrook.
Not reportedTaxon
Verbatim
e0“All these lines flowered significantly earlier than Wesbrook”
Claim · model-written summary
The earliest line flowered at the same time as its B. campestris parent.
- Taxon
- B. campestrisBrassica rapa subsp. oleiferae0
- Material
- earliest flowering linee0
- Outcome
- flowerede0
- Direction
- at the same timee0
- Comparator
- early flowering B. campestris parente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the earliest flowering line flowered at the same time as the early flowering B. campestris parent”