Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/37206
標題: 水稻耐旱性之遺傳研究
Genetic Study on Drought Tolerance in Rice ( Oryza sativa L.)
作者: 林孟輝
Lin, Meng-Huei
關鍵字: rice;水稻;genetic;drought tolerance;遺傳;耐旱性
出版社: 農藝學系
摘要: 
水稻(Oryza sativa L.)屬於淺根系統的作物,對吸收深層土壤水分的能力很有限,對缺乏土壤水分的環境非常敏感,但是乾旱逆境卻威脅全球約50%的耕作面積。因此,本試驗為探討水稻耐旱性之遺傳行為,首先以葉片捲曲度之乾旱敏感指數來檢測國內現有栽培品種的耐旱變異及其對農藝性狀與米質之影響,繼而以兩個雜交組合IR 36 x 台中189號(IR 36 x TC 189)及台中189號 x 台中秈10號(TC 189 x TCS 10)之F2世代在乾旱逆境下探討各農藝性狀的遺傳,並依此進行高產量方向之F3選拔,以分析其選拔效果及遺傳率。最後利用水稻微衛星分子圖譜之系統,來偵測Milyang 23 x 台中189號組合之F2世代控制耐旱基因的位置,依此尋找與耐旱基因緊密連鎖之微衛星標誌,並據圖選殖,以作為遺傳育種之參考。所得試驗結果如下:
在乾旱逆境處理下,參試的30個品種間無論在農藝性狀(除一穗粒數外)、米質性狀(除糙米率外)及處理間均呈顯著性差異。即各農藝性狀及碾米品質之表現均明顯下降,而直鏈澱粉含量及蛋白質含量則有增加的趨勢。當土壤水分張力達20 kPa時,分析各參試品種性狀之反應值( %)與正常灌溉間之相關時,發現並無顯著相關,而土壤水分張力達50 kPa時,分蘗數及產量的變異量呈顯著負相關,稔實率則呈顯著正相關,且在此處理下各品種之農藝性狀的表現經主成分分析結果可區分為三群:一群為對乾旱逆境較不敏感的印度型品種,一群為較敏感的早熟日本型品種,另一群則介於上述兩群間之中晚熟日本型品種。另分析米質性狀在乾旱處理下之反應值與無處理進行相關性比較時,可看出均無顯著相關性,即耐旱品種也可能具優良米質之特性。
兩個IR 36 x TC 189及TC 189 x TCS 10之雜交組合F2雜交後代在乾旱逆境下,株高、穗重、千粒重、一穗穎花數、單株產量等都具有超越兩親的分離,因此可作為特定性狀選拔之參考。
乾旱敏感指數在兩組合中均有相當高的遺傳率(IR 36 x TC 189為99.30,TC 189 x TCS 10為99.38%),且TC 189 x TCS 10具有高遺傳變異(GCV=79.05%),顯示此組合具有較廣的變異潛能。與農藝性狀間之相關性分析中,IR 36 x TC189的指標等級與稔實率呈顯著負相關,與其他性狀間之相關性並不明顯, TC 189 x TCS 10的組合中除分蘗數及一穗穎花數兩性狀外,指標等級與其他性狀間均呈顯著負相關。經主成分因子分析結果可看出,兩組合各性狀間與產量有較密切關係者為穗重及稔實率等二性狀,或可提供吾人進行選拔時參考,即於在乾旱逆境下,在IR 36 x TC 189 與 TC 189 x TCS 10雜交後代中,欲進行產量選拔,應偏向具高稔實率之穗重型植株。但從產量與乾旱敏感指數間的關係中可發現,選拔具有耐旱性的後代有高產量的潛能。
就F2雜交後代之分離情形觀之,IR 36 x TC 189呈1(抗或耐):3(敏感)之比率,表示此組合有關耐旱性之遺傳因子為一對隱性基因。TC 189 x TCS 10則呈9(抗或耐):7(敏感)之比率,表示此組合有關耐旱性之遺傳因子至少有二對。因此有關水稻耐旱性的育種選拔,將依親本的不同,應用在後代選拔方式亦有差異。
自兩雜交組合F2 族群中,在5%選拔強度往耐旱性的方向選拔時,由於乾旱敏感指數在兩組合F2 族群有高遺傳率(99.3%),受環境的影響較小,且生產之F3 系統之平均值均高於F2 族群,即在早期分離世代中進行選拔,就可獲得良好的效果。往產量高的方向選拔時,由於兩組合F2 族群之產量屬中遺傳率(52.1~68.58%),且分布呈右偏現象,欲早期選拔高產量似乎較難達成,但由選拔效果來看,早期的單株選拔仍能累積有效的基因。
應用微衛星標誌(microsatellites)分析,在每條水稻染色體上選取6個以上平均分佈的SSR分子標誌,一共選取80個SSR分子標誌,用來篩選親本台中189號與Milyang 23以及二者之雜交後代F2 族群,約61個SSR分子標誌能分辨親本間多形性,。
將親本間具多形性的46個SSR,進一步在100株F2分析,結果在水稻染色體上,一共有三個基因座和控制耐旱性狀相關,其中以水稻第八條染色體上的RM72相關性最強,R2為13.23%;其次為第十條上的RM228,R2為10.67%;此外第十二條染色體上的RM20A 其R2為9.88%。以RM72及RM20A而言,耐旱性來自於親本M23-3,反之,以在RM228這個位置上,耐旱性來自於親本TC189-3。

Rice(Oryza sativa L.)plant in general have a shallow root system and little water extracted from soil. That is particularly susceptible to soil water deficit, and drought affects its growth in about 50% of the production area in the world. Therefore, the goal of the present study mainly focus on genetic variability of drought tolerance in rice. The main objectives of this study were investigating the ability of rice varieties with drought tolerance associated with leaves rolled which as drought sensitivity index. Next, to study the inheritance of agronomic characters using the parents, F2 population of the crosses between IR 36 and Taichung 189, Taichung 189 and Taichung Sen 10, and estimated heritability based on selection for high freguency. finally, an F2 population derived from a cross of Milyang 23 x Taichung 189 has been screened by rice SSR markers to detect loci associated with drought tolerance in rice. The information obtained from the present study may serve as a reference for breeding. The results showed that:
1. Except spikelet number per panicle and brown rice and the agronomic and rice-quality characters in 30 rice varieties were significantly under treatment of drought.
2. The agronomic and milling quality decreased gradually from soil moisture tension 20 kPa to 50kPa. However, the percentage amylase and crude protein content were to the contrary.
3. There 30 rice varieties could be classified as three clusters according to principal component analysis. The first cluster included Indica type rice varieties were found to be drought tolerance. The second cluster included Japonica type of early maturing rice varieties were susceptible to soil water deficit. The third cluster included Japonica type of late maturing rice varieties were in the middle.
4. Plant height, panicle weight, 1000-grain weight, spikelet number per panicle and grain yield per plant showed exceeding to the parental distributions in F2 populations from crosses IR 36 x Taichung 189 and Taichung 189 x Taichung Sen 10 under drought treatment.
5. The high heritability of drought sensitivity index implied that selections could be executed in early generations.
6. Through principal factor analysis, it was found panicle weight and fertility were close correlated with grain yield of progenies derived from two crosses under drought treatment.
7. The plants were classified as drought resistant or susceptible based on the plasticity of leaf rolling levels. The F2 populations of crosses IR 36 x Taichung 189 were showed segregation ratio of 1 resistance : 3 susceptible. It was assumed that resistance in these genotypes was conditioned by single recessive gene. The cross Taichung 189 x Taichung Sen 10 were showed segregation ratio of 9 resistance : 7 susceptible. This indicated that at least two genes were responsible for drought resistance.
8. A broad-sense heritability of drought sensitivity index based on the F2 variance were high (99.3%). This observation suggests that the selection for a higher frequency is effective and suitable for the early-generation selection process. But broad-sense heritability of grain yield were 52.2~68.5%, and F2 population showed the distribution of skew-to-right exceeding to the parental. This observation suggests that the selection for a higher grain yield frequency is suitable for the later generations selection process, and required for the early generation selection of individuals in which effective alleles are accumulated.
9. A total of 80 SSR markers were used to screen the polymorphism between Milyang 23 and Taichung 189. The result showed three loci were associate with drought tolerance.
URI: http://hdl.handle.net/11455/37206
Appears in Collections:農藝學系

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