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    Three kinds of plant growth regulators, gibberellinA4/7 (GA4/7), 6-benzylaminopurine (BA), and chlormequat chloride (CCC), were evaluated for their ability to promote strobilus and cone production in a Chinese pine (Pinus tabuliformis Carr.) clonal seed orchard. Treatments (0, 250, 500, or 1000 mg⋅L-1) were applied during three periods (June- July, July-August and August-September) in 2005. Of the three plant growth regulators, GA4/7 was the best for promoting flower and cone production. Trees sprayed with GA4/7 (500 mg⋅L-1) from June to September had significantly more female strobili and immature cones than controls and other treatments (p≤0.0001). The best time to apply GA4/7 was in June. BA at 500 mg⋅L-1 significantly increased female flower and immature cone production, compared to other treatments and controls (p≤0.0001), while promotion of male strobili was unchanged. Chlormequat chloride at 1000 mg⋅L-1 significantly increased the number of male strobili, compared to the other treatments (p≤0.0001). Spraying CCC at 500 mg⋅L-1 significantly increased the number of female strobili, compared to controls (p<0.05), but it had no effect on immature cone production (p>0.05). These results are important for improving seed production and seed orchard management of Chinese pine.

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    Zhao, Peng; Fan, Jun-feng; Zhang, Shuo-xin; Huang, Zhong-lian; Yang, Pei-hua; Ma, Zhen-Hua; Woeste, Keith W. 2011. Effects of gibberellin A4/7, 6-benzylaminopurine and chlormequat chloride on the number of male and female strobili and immature cones in Chinese pine (Pinus tabuliformis) with foliar sprays. Journal of Forestry Research. 22(3): 353-359.


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    flower promotion, conifer seed production, breeding, Pinus tabuliformis Carr.

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