化學藥劑誘導玉米孤雌生殖產生同結合倍體之研究

Abstract

本試驗以天然授粉之台南白玉米族群(TNW)為材料，分別於1995年秋及1996年春利用下列藥劑處理組合(A) 40 ppm maleic hydrazide (MH) + 2% dimethyl sulfoxide (DMSO), (B) 40 ppm MH + 2% DMSO + 0.1% colchicine，(C) 40 ppm MH + 2% DMSO + 0.1% colchicine + 10 ppm 2,4-D，(D) 40ppm MH + 2% DMSO + 10 ppm 2,4-D，(E) distilled H2O(ck)施於未受粉之雌花上以誘導玉米孤雌生殖產生同結台二倍體，以做為玉米自交系之來源。在四種劑處理組合中，以A處理所得的結實率最髙，平均1.6 x 10-4。其次為D處理及B處埋，二者平均結實率分別1.4 x 10-4 和1.0 x 10-4，C處理平均結實率為0.4 x 10-4。而以蒸鰡水處理平均結實率最低有0.3 x 10-4。檢查藥劑誘導台南白玉米所穫得種子的根尖細胞染色體數，結果示所有根尖細胞染色體數皆為2n=20並未發現具有混倍數(mixploid)或異倍數體(aneuploid)等異常染色體數存在。各處理所獲得之每一M1單株經人工自交授粉，分別收穫各自交果之種子，採一穗一行播種之，結果共獲得17個M2系行，調查並計算各系行之開花期、吐絲期，株高及穗位高等外表性狀之平均及變異係數，並分別利用OPAH-14、OPAU-01引子於TNW之M2系行以檢定它們的RAPD型性。經由外表性狀及DNA的分析結果可知藥劑誘導台南白玉米衍生而來之M-l、M-4、M-6及M6等四個M2系行為同結台二倍體的後裔行。 An open-pollinated maize population, Tainan-White (TNW), was used as source material in this study. In the fall of 1995 and the spring of 1996, the silks of plant material were treated with the following chemical combinations: (A)40 ppm maleic hydrazide (MH) 2% dimethyl sulfoxide (DMSO), (B) 40 ppm MH + 2% DMSO + 0.1% colchicine, (C) 40 ppm MH + 2% DMSO + 0.1% colchicine + 10 ppm 2,4-D, (D) 40 ppm + 2% DMSO 10 ppm 2,4-D, (E) distilled H2D (ck) to induce the homozygous diploids through parthenogenesis. The car shoot was covered by plastic shoot bag before silk emerged from the husk tip. On the day preceding chemical treatment, the tip of the car was cut within 2 cm long. The chemicals were applied to silk as the silk elongated from the tip, The ear shoot was protected by tassel bag until maturity. The results indicated that the treatment of A gave the highest average kemel setting with the frequency of 1.6 x 10.4 among 5 treatments in TNW maize population. Treatments of B, C and D induced average kemel setting frequency of 1.0 x 104, 0.4 x 10-4 and 1.4 x 104, respectively. Treatment E was the least effective on kernel setting frequency of 0.3 x Root-tip cells from putative homozygous diploids were collected for investigating their chromosome number. All of them had 20 chromosomes. Mixploid and aneuploid were not found in these materials. All of the kernels were grown to maturity and self-pollinated to gel the M: lines. The means and coefficients of variation of days to tasseling, days to silking, plant height and ear height were the four characters to be calculated far measuring the uniformity of the lines. The results indicated that 4 of the 17 lines, M-l, M-4, M-6, and M-16 derived from TNW showed high uniformity of agronomic characters and non polymorphism in RKPD analysis with OPAH-14 and OPAU-OI primers. It suggested that these 4 M2 lines were the homozygous diploids through parthenogenesis.