Landi P, Sanguineti M C, Liu C, Li Y, Wang T Y, Giuliani S, Bellotti M, Salvi S, Tuberosa R
Department of Agroenvironmental Science and Technology (DISTA), University of Bologna, Viale Fanin 44, I-40127 Bologna, Italy.
J Exp Bot. 2007;58(2):319-26. doi: 10.1093/jxb/erl161. Epub 2006 Oct 18.
A major QTL affecting root traits and leaf ABA concentration was identified in maize (Zea mays L.) and named root-ABA1. For this QTL, back-cross-derived lines (BDLs) homozygous either for the (+) or for the (-) allele increasing or decreasing, respectively, root size and leaf ABA concentration, were developed. This study was conducted to evaluate the QTL effects in various genetic backgrounds and at different water regimes. The (+/+) and (-/-) BDLs were crossed with five or 13 inbred tester lines of different origin, thus producing two sets of test-crosses that were evaluated in Italy and China, respectively. Testing was conducted under both well-watered and water-stressed conditions. In Italy, the test-crosses derived from (+/+) BDLs, as compared with those derived from (-/-) BDLs, showed, across both water regimes, higher leaf ABA concentration (on average 384 versus 351 ng g(-1) DW) and lower root lodging (28.0 versus 52.5%), and lower grain yield under water-stressed conditions (4.88 versus 6.27 Mg ha(-1)). In China, where root lodging did not occur, the test-crosses derived from (+/+) BDLs were less productive at both water regimes (on average, 6.83 versus 7.49 Mg ha(-1)). The lower grain yield of the test-crosses derived from (+/+) BDLs was due to a lower number of ears per plant and to lower kernel weight. The results indicate that the (+) root-ABA1 allele confers not only a consistently lower susceptibility to root lodging but also a lower grain yield, especially when root lodging does not occur.
在玉米（Zea mays L.）中鉴定出一个影响根系性状和叶片脱落酸浓度的主要数量性状位点（QTL），并将其命名为root - ABA1。针对该QTL，分别培育出了纯合（+）或（-）等位基因的回交衍生系（BDL），（+）等位基因会增加根系大小和叶片脱落酸浓度，（-）等位基因则会降低这些指标。本研究旨在评估该QTL在不同遗传背景和不同水分条件下的效应。将（+/ +）和（- / -）BDL与5个或13个不同来源的自交测验系进行杂交，从而产生两组测交后代，分别在意大利和中国进行评估。试验在充分供水和水分胁迫条件下进行。在意大利，与来自（- / -）BDL的测交后代相比，来自（+/ +）BDL的测交后代在两种水分条件下均表现出较高的叶片脱落酸浓度（平均为384 ng g(-1) DW，而后者为351 ng g(-1) DW）、较低的根倒伏率（28.0%对52.5%），以及在水分胁迫条件下较低的籽粒产量（4.88 Mg ha(-1)对6.27 Mg ha(-1)）。在中国，未发生根倒伏现象，来自（+/ +）BDL的测交后代在两种水分条件下的产量均较低（平均为6.83 Mg ha(-1)对7.49 Mg ha(-1)）。来自（+/ +）BDL的测交后代籽粒产量较低是由于单株果穗数较少和粒重较低。结果表明，（+）root - ABA1等位基因不仅始终赋予较低的根倒伏敏感性，还导致较低的籽粒产量，尤其是在未发生根倒伏的情况下。
