|Title:||臺灣雜草型紅米之形態歧異度分析||Other Titles:||Morphological diversity study on Taiwan Weedy Red Rice||Authors:||鄭智允
David R. Gealy
|Keywords:||雜草型紅米;形態;主成分分析;Weedy red rice;morphologicaltrial||Issue Date:||Jun-2017||Publisher:||台灣農學會||Journal Volume:||18||Journal Issue:||2||Start page/Pages:||161-188||Source:||台灣農學會報||Abstract:||
臺灣早期品種以高株、短粒型秈稻為主，且紅米混雜氾濫；直到1906～1921年開始系統性防除才讓生產田區的紅米消失；近年不論是稻種繁殖圃或是經濟生產區內，反覆出現具有褐色穀粒的田間異型株，這類異型株因為明顯的紅色種皮，明顯造成稻種純度下降，逐漸演變為稻田中一項新興雜草。本試驗自2014年134個稻種繁殖圃(原種、採種圃)收集的521粒雜草型紅米糙米(weedy red rice, WRR)後，將其細分為3個次族群，同時與2014年推薦的15個稉稻、2個秈稻品種與57個1964年前收集保存的紅米種原，其中包含15個臺灣早期秈稻地方種、42個大陸引進種原，分別於北、中、南3個試驗地點評估雜草型紅米的形態趨勢，藉由抽穗日數、株高、種子脫粒性、糙米顏色與穀粒外觀了解其多樣性與不同時代品種(系)的關聯性。雜草型紅米族群在不同試驗區上，均比近代栽培品種略早熟、脫粒性高、分蘗數多、株高較矮且穩定具有紅色種皮；藉由9個性狀的主成分分析結果，可知不同地區下成熟株型與穀粒外觀均屬區隔類群的重要因子，亦可發現雜草型紅米族群的分散程度與分布位置均與近代栽培品種相近，但榖粒外觀卻近似早期秈稻地方種的粗短型粒型，明顯異於近代細長型秈稻品種與短圓型稉稻品種；推測在稻種繁殖圃中強力汰除高株田間異型株下，榖粒性狀較不受人為選拔影響，暗示著雜草型紅米族群與早期地方種關聯性較高。經本試驗可見雜草型紅米收集系(collection)具有半矮株、早熟、易脫粒等雜草化特性，使其得以多世代繁衍而留存於田區；因此，除了宣導使用合格稻種以減少紅米入侵外，並持續移除異型株或阻斷其繁殖週期進行田區清潔是為防治首要任務。
The Taiwan landraces of early times were tall indica type with short grain and the contamination of red rice accessions was once very serious on Taiwan paddy field before 1906. In order to improve grain quality, systematic efforts were conducted to remove off-type plant with red pericarp by hand from paddy field during 1906 to 1921. In recent years, the off-type plants with red pericarp increased vastly on rice seed fields and paddy fields of economic production to reduce the purity of rice seed. We collected 521 weedy red rice individuals, which derived from 134 registered and certified seed fields, and then divided into three groups in multiple regions trials. The three groups of weedy red rice, which were evaluated by nine traits in three locations, compared with 74 check varieties including 15 modern japonica cultivars, 2 indica cultivars, 15 Taiwan native landraces and 42 mainland Chinese landraces. The results showed that the weedy red rice population possessed the morphological trend was early maturity, higher shattering, high panicle number, semi dwarf and red pericarp compared with the other modern cultivars. The results of principle component analysis (PCA) exhibited that the first two principle components were plant type and grain shape. In the two-dimensional plot of PCA, the morphological diverse and population location of Taiwan weedy red rice was closed with modern japonica cultivar across three locations. However, the selection strength of off-type individual for plant height was higher than the grain shape in the seed fields. The information of grain shape could provide the genetic relationship among Taiwan weedy rice and other material groups. In advance, the grain length-width ratio suggested the genetic relationship of Taiwan weedy rice population was closer with Taiwan native indica landraces, but was different with the long-grain or short-grain of modern cultivars. The study showed the off-type individuals with red pericarp would be easily maintained on the soil seed bank of paddy field due to the off-type plants with many weedy characteristics. In future, the control strategy should be not only on the management of qualified seed to reduce the invasion of weedy red rice, but also carry out the field cleaning jobs though removing of off-type plants and stopping its life cycle.
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