A previous study conducted on a maize (Zea mays L.) mapping population derived from Os420 × IABO78 identified a quantitative trait locus (QTL) for leaf-abscisic acid concentration (L-ABA) on chromosome 2 (bin 2.04). In order to validate this QTL, we analyzed with RFLP markers 16 F4 lines obtained by divergent selection for L-ABA from the same source. Three RFLPs mapping near bin 2.04 showed skewed allelic frequencies; the L-ABA increasing allele (+) was more frequent within the eight lines selected for high L-ABA, while the decreasing allele (-) was more frequent within the eight lines selected for low L-ABA. To characterize more accurately the direct and associated effects of this QTL, near-isogenic lines were developed by molecular marker-assisted back-crossing; four backcross-derived lines were homozygous (+/+) at the QTL and four were (-/-). A pair of near-isogenic hybrids (+/+) and (-/-) at the QTL were also produced. These materials were field tested under water-stressed and well-watered conditions. Across water regimes, the four (+/+) lines averaged a significantly higher mean value than the four (-/-) lines for L-ABA (494 vs. 396 ng ABA g-1 DW) and a significantly lower mean value for relative water content (90.6 vs. 92.0%). The (+/+) hybrid exceeded the (-/-) for L-ABA (476 vs. 325 ng g-1 DW) and was less affected by root lodging (44.6 vs. 66.1%). Our results validate the presence of a major QTL for L-ABA on bin 2.04 and indicate that the QTL also affects root traits and relative water content.
LANDI P., SANGUINETI M.C., SALVI S., GIULIANI S., BELLOTTI M., MACCAFERRI M., et al. (2005). Validation and characterization of a major QTL affecting leaf ABA concentration in maize. MOLECULAR BREEDING, 15 (3), 291-303 [10.1007/s11032-004-7604-7].
Validation and characterization of a major QTL affecting leaf ABA concentration in maize.
LANDI, PIERANGELO;SANGUINETI, MARIA CORINNA;SALVI, SILVIO;GIULIANI, SILVIA;BELLOTTI, MASSIMO;MACCAFERRI, MARCO;CONTI, SERGIO;TUBEROSA, ROBERTO
2005
Abstract
A previous study conducted on a maize (Zea mays L.) mapping population derived from Os420 × IABO78 identified a quantitative trait locus (QTL) for leaf-abscisic acid concentration (L-ABA) on chromosome 2 (bin 2.04). In order to validate this QTL, we analyzed with RFLP markers 16 F4 lines obtained by divergent selection for L-ABA from the same source. Three RFLPs mapping near bin 2.04 showed skewed allelic frequencies; the L-ABA increasing allele (+) was more frequent within the eight lines selected for high L-ABA, while the decreasing allele (-) was more frequent within the eight lines selected for low L-ABA. To characterize more accurately the direct and associated effects of this QTL, near-isogenic lines were developed by molecular marker-assisted back-crossing; four backcross-derived lines were homozygous (+/+) at the QTL and four were (-/-). A pair of near-isogenic hybrids (+/+) and (-/-) at the QTL were also produced. These materials were field tested under water-stressed and well-watered conditions. Across water regimes, the four (+/+) lines averaged a significantly higher mean value than the four (-/-) lines for L-ABA (494 vs. 396 ng ABA g-1 DW) and a significantly lower mean value for relative water content (90.6 vs. 92.0%). The (+/+) hybrid exceeded the (-/-) for L-ABA (476 vs. 325 ng g-1 DW) and was less affected by root lodging (44.6 vs. 66.1%). Our results validate the presence of a major QTL for L-ABA on bin 2.04 and indicate that the QTL also affects root traits and relative water content.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.