稉稻「台農71號」高產潛能近同源系產量特性及生產力提升評估

Abstract

本研究於2013-2014年在行政院農業委員會農業試驗所農場(臺中市霧峰區)進行二年期間一、二期稻作之稉稻高產潛能近同源系之生長與產量特性評估試驗，期以未來有助於提升稉稻生產力。田間試驗以導入多粒數(Gn1)、半矮性株高(sd1)或高光合作用(qCAR4 and qCAR11)等具有可能高產潛能特性之「台農71號(TNG71)」近同源系為試材，以釐清其基因特性表現在生長及產量貢獻之權重，並以評估未來應用於稉稻生產力提升之可行性。調查性狀包括株高、生質量及產量性狀等，另亦探討不同氮素施用量對其等影響。試驗結果在株高表現部分，發現帶有半矮性基因之「台農71號sd1」在一、二期作及不同氮素施用量上，其株高表現均顯著地低於輪迴親「台農71號」，顯示sd1半矮性基因特性確有反映於田間試驗結果。在生質量(即乾物質)結果上，顯示帶有高光合作用基因之「台農71號qCAR11」除了2013年二期作之132kg N ha^(-1)及2014年一期作之180kg N ha^(-1)處理表現低於「台農71號」之外，其餘處理乾物質表現均高於「台農71號」。在產量性狀方面，帶有多粒數基因之「台農71號Gn1」每穗穎花數均高於「台農71號」，即Gn1多粒數基因於田間有明顯反映其特性。在稔實率部分，以「台農71號qCAR11」之表現最佳，其次分別為「台農71號」、「台農71號qCAR4」及「台農71號sd1」，而以「台農71號Gn1」表現最差。在20132014年一期作之千粒重部分，以「台農71號qCAR11」及「台農71號qCAR4」表現均優於「台農71號」。2013-2014年一期作之「台農71號」近同源系穀粒產量比較結果，以「台農71號qCAR11」產量表現最佳，其次則是「台農71號」及「台農71號qCAR4」，而「台農71號Gn1」及「台農71號sd1」產量表現普遍較低。增加氮肥施用量，雖可些微提高部分「台農71號」近同源系之穀粒產量，惟其表現均未達顯著性差異。「台農71號」近同源系於2013-2014年一期作抽穗前7-10日及抽穗時期之淨光合作用速率，以「台農71號qCAR11」較高，符合其高穀粒產量結果。綜合本研究試驗，顯示「台農71號Gn1」雖可增加每穗穎花數，然而其光合作用速率表現不佳，導致光合產物供應不足而無法提升穀粒產量，未來若可進一步聚合高光合作用效率基因座(qCAR11及qCAR4)之供源特性，或可期待選育出供源與積儲平衡之高產潛能新品系。 Field experiments were conducted at Taiwan Agricultural Research Institute Experimental Farm (Wufeng District, Taichung City) in 2013-2014, with two cropping seasons for each year. The objectives are to assess the varietal differences in yield components among rice high yielding potential near-isogenic lines in aid of productivity improvement in japonica rice in the future. The introgressions of four yield-related loci, including high grain number gene (Gn1), semi-dwarf gene (sd1) and high photosynthetic efficiency genes (qCAR11 and qCAR4), from variety 'Habataki' were transferred to cultivar 'Tainung 71' by marker-assisted backcross selection respectively to study their contribution to growth and yield. The characteristics of plant height, biomass, yield and yield components were investigated for assessment. Effect of different nitrogen application rates on grain yield was also examined. Results showed that plant height of the line 'TNG71-sd1' was lower than the recurrent parent 'TNG71' under differential nitrogen rates in both cropping seasons, suggesting that sd1 gene has been successfully introduced. Except treatments of 132 kg N ha-1 in the second crop of 2013 and 180 kg N ha-1 in the first crop of 2014, the line 'TNG71-qCAR11' had larger biomass (dry weight) than 'TNG71'. For yield components, the line 'TNG71-Gn1' had higher spikelets per panicle than its recurrent parent and the line 'TNG71-qCAR11' had the highest percent filled grains among others while the line 'TNG71-Gn1' had the least. The 1000-grain weight in the lines 'TNG71-qCAR11' and 'TNG71-qCAR4' were superior to 'TNG71' in the first cropping season of both years. For First Crop, yield of the line 'TNG71-qCAR11' was the highest and 'TNG71-sd1' and 'TNG71-Gn1' were the poorest. Increases in nitrogen fertilizer application rate had only slightly improved grain yield of these near-isogenic lines but it did not reach statistical significance. The better yield of the line 'TNG71-qCAR11' in First Crop may be attributed to a higher photosynthetic rates in seven to ten days prior to heading and in the early stage of grain-filling. As a result, with the increase of spikelets per panicle plus an introduction of high photosynthetic efficiency loci (qCAR11 and qCAR4) in future, the 'TNG71-Gn1' would be the potential line for a possible increase in rice productivity.