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China National Rice Research Institute Hangzhou, China
The genetic analysis of semi-dwarfism in three Yunnan Indica varieties: Hong-
ke-dao (71.1cm), Ai-ma-bai-gu (71.1 cm), Bai-hua-puo (74.1 cm) and one local
Japonica variety Xue-he-ai-zao (71.4 cm) was carried out during 1984-1986. The
results are summarized as follows:
Table 1. Genetic analysis of Xue-he-ai-zao
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Cross Height F2 or BC1 segregation for Expected X2
of F1 height ratio
==========================
Tall Dwarf Double
dwarf
(no.) (no.) (no.)
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Xue-he-ai-zao/ Tall 379 137 0 3:1 0.581
Lao-lai-qing*
Xue-he-ai-zao2/ 61 65 0 1:1 0.071
Lao-lai-qing
Xue-he-ai-zao/ Tall 410 148 0 3:1 0.611
Ban-jie-mang*
Xue-he-ai-zao2 43 49 0 1:1 0.532
Ban-jie-mang
Ai-gan-nuo**/ Tall 309 179 36 9:6:1 2.575
Xue-he-ai-zao
Ai-gan nuo2/ 49 47 0 1:1 0.010
Xue-he-ai-zao
Dan 215**/ Tall 247 198 30 9:6:1 3.753
Xue-he-ai-zao
Dan 2152/ 35 28 0 1:1 0.571
Xue-he-ai-Zao
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*Lao-lai-qing and ban-jie-mang are tall varieties**Ai-gan-nuo and Dan 215 are semi-dwarf japonicas with sd-1 dwarfing gene
Table 2. The changes in plant height and flag leaf length in 10 rice
varieties after GA\3\ treatment
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Variety Plant height %increase Flag leaf %increase
============== over ============= over
CK 100ppm check CK 100ppm check
=============================================================================
Indica:
1. Hong-Ke-Dao 71.1 81.0 13.9 18.5 27.8 50.3
2. Ai-Ma-Bai-Gu 71.1 84.5 17.9 25.9 33.6 29.7
3. Bai-Hua-pi-Nu 74.1 90.6 22.3 24.7 38.6 56.3
4. Ai-Jiao-Nan-Te 58.2 65.4 12.4 21.4 29.5 37.9
5. IR36 75.5 87.6 16.0 22.1 27.7 25.3
6. Zhen-Zu-Ai 75.7 87.9 16.1 18.2 27.7 52.2
7. Cong-Gui-314 84.0 89.0 6.0 18.2 21.0 15.4
Japonica:
8. Xue-He-Ai-Zao 71.1 72.9 2.5 16.2 19.0 17.3
9. Ai-Gan-Nuo 53.0 62.8 18.5 14.3 22.9 60.1
10.Reimei 71.6 83.1 16.1 13.7 19.0 38.7
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*1-6 = Indica varieties with sd-1 gene; 7 = An indica promising line from
Guangdong Academy of Agricultural Sciences with an unknown semidwarfing gene.
1. Each of the three semi-dwarf Indica varieties has a single recessive gene
for short stature which is allelic to sd-1. These results indicate that sd-1 is
wide-spread even among the Yunnan local varieties. The semi-dwarfism of Xue-he-
ai-zao is also controlled by a single recessive gene, which is non-allelic to
sd-1 (Table 1).
2. It has been reported that the sd-1 gene is sensitive to GA 3. A further investigation was undertaken using 10 semi-dwarf varieties (7 Indicas and 3 Japonicas). Each variety was sprayed with freshly-prepared 100 ppm solutions of GA3 at booting stage. Spray with pure water was used as a control treatment. Plant height and the flag leaf length at full maturity of all varieties with sd-1 gene increased significantly as a result of GA treatment. Two varieties, Cong-gui 314 and Xue-he-ai-zao did not respond to GA3 (Table 2). It is obvious that "GA3 responses" may be used both in Indica and Japonica varieties as a criterion for rapidly identifying those with sd-1 genes.
