DEVELOPMENT OF HIGH YIELDING, DISEASE RESISTANT, YELLOW-SEEDED BRASSICA NAPUS
G. Rakow , J. Relf-Eckstein, J.P. Raney and R. Gugel
Agriculture and Agri-Food Canada, Saskatoon Research Centre,
107 Science Place, Saskatoon, SK, Canada, S7N 0X2
The development of yellow-seeded forms of Brassica napus has been a major focus of breeding research at AAFC Saskatoon for the last 20 years.� The original yellow-seeded germplasm was low yielding, highly susceptible to blackleg disease, and the seed had a low oil content.� In 1991, a cross was made between the yellow-seeded line YN90-1016 and the black-seeded, blackleg resistant Australian variety Shiralee, followed by a cross to the high oil content breeding lines N89-17 and N89-53.� The two crosses were pedigree selected and five near isogenic yellow/black seeded pairs, consisting of 20 F5 derived sublines for each pair, were field tested from 1996 to 1998.� Genetically stable, true breeding yellow-seeded lines were identified that had high oil content were resistant to blackleg and had high yield.� The results of the field tests indicated that the yellow-seeded line YN90-1016 can successfully be used a source of the yellow seed trait in crosses with black-seeded germplasm to improve the agronomic performance and seed quality of yellow-seeded B. napus. Selected F7 lines of the yellow-seeded F4 line YN94-663, derived from the above cross, are presently used as parents in crosses with various black-seeded B. napus germplasm to produce commercially competitive, high yielding, high oil content, canola quality B. napus varieties for production in western Canada.
KEYWORDS: Oil content, seed quality, blackleg disease.
Research towards the development of yellow-seeded Brassica napus has been conducted for many years by various research groups around the world.� The interest is in this work resulted from observations which compared the quality of the seed of yellow and brown-seeded forms of B. rapa (Stringam et al. 1974), B. juncea (Woods 1980) and later also B. carinata (Getinet et al. 1996).� In all cases, yellow-seeded forms had significantly higher oil contents than their brown-seeded counterparts and the meal derived from yellow seeds had higher protein and lower crude fibre contents than that of brown seeds.� Increases in oil content of Brassica oilseeds are of particular importance since oil is the most valuable component of the crop.� However, in B. napus, no yellow-seeded types occur naturally.� All yellow-seeded B. napus lines studied have been developed through interspecific hybridizations with yellow-seeded forms of B. rapa, B. juncea and B. carinata in various crossing combinations.� Liu and his colleagues in China utilized yellow-seeded B. chinensis in crosses with B. napus to develop yellow-seeded B. napus (Liu 1983), and a first yellow-seeded variety �HUA-yellow No. 1� was registered for commercial production in 1990 (Liu, et al. 1991).� The average oil content of this variety was 5-7% higher than that of black seeded varieties during four years of testing from 1983/84 to 1986/87.� Shirzadegan and R`bbelen (1985) in Germany crossed a re-synthesized yellow-brown seeded B. napus, derived from an interspecific cross between light yellow-brown seeded B. oleracea ssp. alboglabra and yellow-seeded B. rapa, with the winter rape variety Quinta to develop yellow-seeded winter rape.� Selections for yellow-seeded plants segregating from this cross were pedigree selected and the quality of the seed compared with that of black-seeded lines.� They found that, on average, yellow seeded lines had lower oil contents than black seeded lines which was attributed to poor embryo development in yellow lines.� Early research at AAFC Saskatoon in developing yellow-seeded B. napus also indicated that yellow-seeded lines, derived from interspecific crosses, had low oil contents, were highly susceptible to blackleg disease and were low yielding.� The objective of this research was to determine if the yellow-seeded line YN90-1016 could be used as a donor of genes for yellow seed in crosses with black-seeded, blackleg resistant and high oil content lines to develop agronomically improved, high quality, yellow-seeded B. napus lines.
MATERIALS AND METHODS
The yellow-seeded B. napus line YN90-1016 was developed at the Saskatoon Research Centre from a complex cross involving the black-seeded, canola quality B. napus variety Regent, yellow-seeded B. rapa yellow sarson, yellow-seeded B. carinata and yellow-seeded B. juncea.� Pedigree selection was used to isolate yellow-seeded plants in segregating generations after crosses which resulted in the identification of the true breeding, yellow-seeded line YN90-1016.� In comparison to the black-seeded variety AC Excel, line YN90-1016 had 4.4% lower oil content, and its yield was only 75% of AC Excel (average of two yield tests, Saskatoon and Scott, Sask., 1996).� In 1991, the yellow-seeded line YN90-1016 was crossed with the highly blackleg resistant Australian canola-quality B. napus variety Shiralee. The F1 was then crossed, as the male, with two canola-quality F4 lines, N89-17 and N89-53, selected for high oil content and derived from the cross between the Canadian B. napus varieties Midas and Westar.� The oil contents of N89-17 and N89-53 were 3% absolute higher than that of the B. napus canola variety Legend in three years of multilocation co-operative tests in western Canada from 1993 to 1995. The F1 generation of the 3-way cross, consisting of 320 plants, was grown in the greenhouse and F2 seed produced.� A total of 300 F2 progeny were grown in the field in a single row, 3-replicate nursery in 1993.� Twenty nine �yellow-seeded� F2 progeny were selected and grown as F3 lines in a double row, 2-replicate nursery in 1994; and nine highest oil content progeny selected.� The seed colour of these nine lines was a mixture of yellow and black seeds.� Approximately 1000 yellow seeds were selected by hand from each of the nine bulk seed samples, and only these were further tested as F4 lines in 1995.� Five hundred plants were individually harvested from each of the nine F4 lines, a total of 4,500 plants.� Seven of the nine families segregated yellow and black seeded plants.� Twenty yellow-seeded (hand selected for yellow seed) and 20 black-seeded plants were selected from each of the seven families, and progeny tested as F5 lines in a double-row, 2-replicate nursery in 1996, for a total of 280 progeny.� A third replicate was planted for the production of 20 single plants (selfed) for further pedigree selection from each line.� The nine F5 lines were also included in a 3-location yield test in 1996 to assess their agronomic potential.� The row nursery was combine harvested, and the seed rated for colour and analyzed for oil and protein content.� Five F5 families were selected based on overall family performance (colour, oil and protein).� Five highest oil and five highest protein F5 lines were selected from both the yellow and black seeded sublines of each family.� Seed of 20 single F5 plants produced in the third replicate of the 1996 nursery was then used for planting on F�6 double-row, 2-replicate nursery in 1997.� The 1997 nursery consisted of 18x5=90 highest oil lines and 18x5=90 highest protein lines for a total of 180 F6 lines each from the yellow-seeded as well as the black-seeded near isogenic sublines of each family for a total of 1800 lines, excluding checks.� The nursery rows were combine harvested and the seed analyzed for seed colour, oil and protein.� A 5% selection was applied to each group (oil and protein, yellow and black) to reduce the total number of lines to 100 which were tested in five, 4-replicate yield tests at three locations in 1998.
We present here the results of the 1997 and 1998 field tests for seed colour, oil content and yield of� near-isogenic yellow/black seeded lines and compare their performance with that of the yellow-seeded parent line YN90-1016 and the average of the high oil content parents N89-17 and N89-53 (Table 1).� The seed colour of the yellow-seeded lines ranged from �14 for YN94-669 to �23 for YN94-660 and YN94-670 in 1997.� There was some improvement in seed colour as the result of selection for yellow
Table 1.������ Average seed colour, oil content and yield of near-isogenic yellow/black seeded lines of Brassica napus canola, Saskatchewan, Canada, 1997-98
|
|
�� Seed colour1 �� |
������������������������������� Oil content (%)���������������������������������������� |
Yield (rel.)6 |
||||||
|
Family |
1997 |
1998 |
Av. of lines 1997����� 1998 |
Dif. to YN90-10162 1997�������� 1998 |
Dif. to N89-17/533 � 1997�������� 1998 |
1998 |
|||
|
YN94-660 |
|
|
|
|
|
|
|
|
|
|
Yellow |
� -234 |
� -255 |
��� 42.9 |
��� 39.2 |
���� -0.1 |
���� -0.1 |
���� -5.1 |
���� -4.0 |
������ 74 |
|
Black |
���� -2 |
���� -6 |
��� 48.9 |
��� 44.2 |
��� +5.9 |
��� +4.9 |
��� +0.6 |
��� +1.0 |
������ 94 |
|
Difference |
|
|
���� -6.0 |
���� -5.0 |
|
|
|
|
���� -20 |
|
|
|
|
|
|
|
|
|
|
|
|
YN94-663 |
|
|
|
|
|
|
|
|
|
|
Yellow |
�� -19 |
�� -30 |
��� 49.5 |
��� 43.3 |
��� +4.2 |
��� +4.3 |
���� -1.1 |
��� +1.0 |
���� 101 |
|
Black |
���� -2 |
���� -6 |
��� 49.8 |
��� 43.1 |
��� +4.5 |
��� +4.1 |
���� -0.8 |
��� +0.8 |
���� 100 |
|
Difference |
|
|
���� -0.3 |
��� +0.2 |
|
|
|
|
����� +1 |
|
|
|
|
|
|
|
|
|
|
|
|
YN94-669 |
|
|
|
|
|
|
|
|
|
|
Yellow |
�� -14 |
�� -24 |
��� 49.9 |
��� 42.2 |
��� +4.1 |
��� +3.3 |
���� -0.8 |
���� -0.2 |
��� 84 |
|
Black |
���� -4 |
���� -8 |
��� 50.1 |
��� 41.8 |
��� +4.4 |
��� +2.8 |
���� -0.6 |
���� -0.7 |
� ��99 |
|
Difference |
|
|
���� -0.2 |
��� +0.4 |
|
|
|
|
�� -15 |
|
|
|
|
|
|
|
|
|
|
|
|
YN94-670 |
|
|
|
|
|
|
|
|
|
|
Yellow |
�� -23 |
�� -24 |
��� 45.2 |
��� 39.1 |
���� -0.7 |
��� +0.1 |
���� -5.5 |
���� -2.8 |
������ 73 |
|
Black |
���� -1 |
���� -5 |
��� 48.8 |
��� 42.4 |
��� +2.9 |
��� +3.5 |
���� -1.9 |
��� +0.5 |
���� 101 |
|
Difference |
|
|
���� -3.6 |
���� -3.3 |
|
|
|
|
���� -28 |
|
|
|
|
|
|
|
|
|
|
|
|
YN94-679 |
|
|
|
|
|
|
|
|
|
|
Yellow |
�� -15 |
�� -20 |
��� 48.6 |
��� 41.6 |
��� +2.6 |
��� +2.7 |
���� -1.5 |
���� -1.2 |
������ 72 |
|
Black |
���� -2 |
���� -6 |
��� 49.1 |
��� 42.2 |
��� +3.1 |
��� +3.3 |
���� -1.0 |
���� -0.6 |
������ 86 |
|
Difference |
|
|
���� -0.5 |
���� -0.6 |
|
|
|
|
���� -14 |
1 HunterLab reflectance colour measurements, high negative values indicate light coloured seed.
2 YN90-1016 = yellow-seeded parent
3 N89-17/53 = high oil content parents
4 Average of 180 lines, of which 90 were selected for high oil and 90 for high protein
5 Average of 10 lines, 3-location yield tests
6 Yield relative to standard check varieties AC Excel, Legacy, Defender
seed, particularly in YN94-663 with colour ratings of -19 in 1997 and �30 in 1998.� Colour ratings of �25 to �30 represent bright yellow seeds.� Oil contents of near-isogenic yellow/black pairs were variable.� Yellow-seeded sublines of family YN94-660 had 6.0% (1997) and 5.0% (1998) lower oil
content than their black-seeded counterparts; and these oil contents were the same as those of the yellow-seeded parent YN90-1016.� On the other hand, oil contents of yellow-seeded sublines of family YN94-663 were identical to those of their black-seeded counterparts, and similar to those of the high oil content parents N89-17/53.� These results clearly indicated that the yellow seed trait of YN90-1016 is not associated with a lower oil content, and that YN90-1016 can therefore be used as a source of the yellow seed trait in crosses with black-seeded, high oil content B. napus lines to develop high oil content, yellow-seeded B. napus.
Seed yields of yellow-seeded lines were, on average, lower than those of their black-seeded near-isogenic counterparts in four of the five families studied.� The average yield of yellow-seeded lines of family YN94-663 were, however, identical to those of black seeded sublines and to standard check varieties of B. napus canola used in official variety tests.� This result indicated that the yellow seed colour in B. napus can be successfully combined with high oil contents and high seed yields which is a highly significant finding.
The yellow-seed characteristic in Brassica seed is of particular importance for the improvement of meal quality in canola (Simbaya et al. 1995).� We initiated selection for protein content, and will also conduct meal fibre determinations and selections in this material.� The results of these studies will be reported elsewhere.
This project was financially supported, in part, by grants from Canodev Inc., a subsidiary of the Saskatchewan Canola Development Commission, Saskatoon, Canada, and by the Matching Investment Initiative of the Government of Canada.� The technical assistance of D. Rode,
D. Hennigan and G. Serblowski is greatly acknowledged.
Getinet, A., Rakow, G. and Downey, R.K. 1996.� Agronomic performance and seed quality of Ethiopian mustard in Saskatchewan.� Canadian Journal of Plant Science, 76:387-392.
Liu, H.L. 1983.� Studies on the breeding of yellow seeded Brassica napus L. Proceedings of the 6th International Rapeseed Congress, Paris, France, Vol. 1: 637-641.
Liu, H.L., Han, J.X. and Hu, X.J. 1991.� Studies on the inheritance of seed coat colour and other related characteristics of yellow seeded Brassica napus. Proceedings of the 8th International Rapeseed Congress, Saskatoon, Canada, Vol. 5: 1438-1444.
Shirzadegan, M. and R`bbelen, G. 1985.� Influence of seed colour and hull proportions on quality properties of seeds in Brassica napus L. Fette, Seifen, Anstrichmittel, 87: 235-237.
Simbaya, J., Slominski, B.A., Rakow, G., Campbell, L.D., Downey, R.K. and Bell, J.M. 1995.� Quality characteristics of yellow-seeded Brassica seed meals:� protein, carbohydrates and dietary fibre components. Journal of Agricultural and Food Chemistry, 43: 2062-2066.
Stringam, G.R., McGregor, D.I. and Pawlowski, H.S. 1974.� Chemical and morphological characteristics associated with seed coat colour in rapeseed. Proceedings of the 4th International Rapeseed Congress, Giessen, Germany, pp. 99-108.
Woods, D.L. 1980.� Association of yellow seed coat colour with other characteristics in mustard (Brassica juncea). Eucarpia Cruciferae Newsletter, 5: 23-34.