高粱株高之基因定位

高粱[Sorghum bicolor (L.) Moench] 為世界上第五大榖類作物，其用途非常廣泛。而不同用途之高粱有不同的株高偏好，生產生質酒精的高粱需要較高大的植株，而收穫種子的高梁則偏好半矮株。目前在臺灣高粱之主要用途為釀酒用，種植期間若遭遇颱風過高的植株會倒伏，故研究影響株高的QTL非常重要。本研究利用兩個糯性高粱品系F7X與E28A6雜交所產生的F_2族群進行株高基因的定位，並且利用混合分離族群分析法(BSA)、單一標誌分析法以及區間定位法進行階段式的基因定位，先找出與株高相關之分子標誌，再集中於與性狀相關之分子標誌週圍區域進行基因定位。研究結果發現在第二、六(2個)與七條染色體中共有4個與株高相關之QTL，包括sbHT2-2(第二條染色體)能解釋8.59%的變異，sbHT6a-59及sbHT6b-23(第六條染色體)則分別可解釋8.10%及16.97%的變異，及sbHT7-51(第七條染色體)則可影響10.19%的株高變異，而sbHT6b-23與sbHT7-51之間還存在交感效應，能影響5.75%的株高變異，此4個QTL組成的線性模式共能解釋約41%的株高變異。本研究定位出的QTL均能對應到前人研究中株高或株高相關性狀之候選基因，例如〖Dw〗_3、hda、Floricaula/leafy-like 2等基因。本研究推薦以TXP176、TXP295、TXP298及SB3479等4個分子標誌輔助株高之選拔，在4個分子標誌中，帶有兩對或三對矮化基因型植株較適合台灣環境的株高，而帶有兩對或三對顯性基因型植株則擁有中等株高，則亦適合作為雜交父本。且F_2族群中有2植株在4個分子標誌中帶有兩對矮化基因型，1株在三個分子標誌都為矮性基因型，有6株三個分子標誌均為顯性基因型，而有1株在4個分子標誌均為同型結合顯性基因型，上述9植株中有4植株在4個分子標誌均已為同型結合，可評估其他性狀做後續之利用。本研究的結果能應用在高粱育種計畫之中，可加速選育具有合適株高之優良高粱品種。

關鍵字

株高；高粱；分子輔助選種

並列摘要

Sorghum [Sorghum bicolor (L.) Moench] is the fifth most important crop in the world. It has various utilizations. There are different preferences correlated with plant height for different uses. For example, the taller plants of sorghum are suitable for bio-energy. On the contrary, the semi-dwarf sorghum for seed production is recommended. In Taiwan currently, the main use of sorghum is brewing wine. To avoid the damage from typhoon, studies on QTLs affecting plant height are very important. In the study, a F_2 population crossed from two waxy sorghum inbred lines, (F7X and E28A6), was used. Bulk Segregant Analysis (BSA) was applied to find out the molecular markers linked with QTL affecting plant height, and interval mapping to locate the QTLs on the chromosomes. Four plant-height QTLs on chromosomes 2, 6, and 7 were mapped. The most significant QTL sbHT6b-23 is on the chromosome 6 and can it explain 16.97% variation of plant height. The other mapped QTLs were sbHT2-2 (chromosome 2), sbHT6a-59 (chromosome 6) and sbHT7-51 (chromosome 7), respectively explaining 8.59%, 8.10% and 10.19% of variation. We also observed interaction between sbHT6b-23 and sbHT7-51. The interaction could explain 5.75% of variation. These four QTLs and interaction would totally explain 41% of plant height variation. All mapped QTL are corresponding to genes in previous studies, like 〖Dw〗_3, had, and Floricaula/leafy-like 2. For marker-assisted selection, we recommend four SSR markers, TXP176, TXP295, TXP298 and SB3479. The plants carrying two or three homologous dwarf genotypes might be suitable for growth in Taiwan and those carrying two or three dominate homologous genotypes are idea to be the male parent for F1 hybrid production. In the F_2 population, there are two plants carrying two dwarf genotypes, one plants with three dwarf, six plants with three tall genotypes and one plant with four tall homologous genotypes. Notably, we found four plants with homologous genotypes for the four SSR markers closely linked with QTL affecting plant height. These four plants were selected for further evaluation. The results of the study could apply in sorghum breeding programs to select sorghum varieties with suitable plant height.

並列關鍵字

Plant height ； Sorghum ； Marker assisted selection

參考文獻

林俊義、賴瑞聲。2007。台灣地區生質酒精作物評估。農業試驗所技術服務 70：1-6。

Ayana, A. and Bekele, E. (1998). Geographical patterns of morphological variation in sorghum (Sorghum bicolor (L.) Moench) germplasm from Ethiopia and Eritrea: qualitative characters. Hereditas, 129(3), 195-205.

Bomblies, K., R.-L. Wang, B.A. Ambrose, R.J. Schmidt, R.B. Meeley and J. Doebley. 2003. Duplicate FLORICAULA/LEAFY homologs zfl1 and zfl2 control inflorescence architecture and flower patterning in maize. Development 130: 2385-2395.

Broman, K.W., H. Wu, Ś. Sen and G.A. Churchill. 2003. R/qtl: QTL mapping in experimental crosses. Bioinformatics 19: 889-890.

Brown, P., P. Klein, E. Bortiri, C. Acharya, W. Rooney and S. Kresovich. 2006. Inheritance of inflorescence architecture in sorghum. Theor Appl Genet 113: 931-942.

國際替代計量

高粱株高之基因定位

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