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Using a three-line system of Shaan 2A cytoplasmic male sterility, a hybrid variety rapeseed, Zhongyouza 11, was developed by the combination of traditional methods and a molecular marker-assisted breeding technique. This hybrid variety had high grain yield, high oil content, wide adaptability, and good quality. The oil content of Zhongyouza 11 is steadily above 43% in the three ecological regions along the Yangtze River valley, which is the largest winter oilseed production area in China. The highest oil content of Zhongyouza 11 reached 46.68% in the upper reaches of the Yangtze River valley in 2003-2004, which was the highest among all lines involved in the national regional rapeseed variety trials. In the regional yield trials in Hubei Province, the average yield of Zhongyouza 11 reached 2853 kg ha^(-1) (2002-2004), yielding more than the control variety Zhongshuang 6 by 11.34%. In the national trials, the yield of Zhongyouza 11 reached 2405.7, 2697.3, and 2770.2 kg ha^(-1) in the upper, middle, and lower reaches of the Yangtze River valley, yielding more than the control varieties by 11.52, 12.9, and 14.92%, respectively, in 2003-2005. Both the high oil content and high grain yield contributed to the high oil yield of Zhongyouza 11. The oil yield of Zhongyouza 11 in the national trials reached 1083.3, 1210.2, and 1224.8 kg ha^(-1), yielding more than the controls by 29.42, 27.65, and 20.98%, respectively, in the upper, middle, and lower reaches of the Yangtze River valley. The highest oil yield reached 1369.65 kg ha^(-1) in the middle reach of the Yangtze River valley (2003-2004), with an increase of 46.21% compared to the control. The experimental sites distributed widely along the Yangtze River valley, cover most of the Chinese winter rapeseed production areas. Among the 89 experimental location! years, the yield of Zhongyouza 11 surpassed the controls at 77 location/years in the trials, indicating its wide adaptability. Zhongyouza 11 was the only one that passed the national regional trials in all three regions along the Yangtze River valley simultaneously in 2005. It is also the first rapeseed variety that contained seed oil exceeding 46% and passed the national regional trials. This study shows that heterosis prediction by the means of estimation of genetic distance between parental lines using single sequence repeat (SSR) and sequence related amplified polymorphism (SRAP) markers is an efficient way for the reduction of tedious field trials and the acceleration of breeding procedure. |
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