| In rice, panicle apical abortion (PAA) exerts a detrimental effect on final yield. In this study, we conducted a genetic analysis to a PAA mutant L-05261, and further dissected its genetic constitution through QTL analysis. The results suggested that there are at least 3 QTLs qPAA3, qPAA5, qPAA8 on chromosome 3, 5 and 8 respectively, responsible for the phenotype of panicle apical abortion. Subsequently, we developed 3 sub-populations aiming to fine map qPAA3, qPAA5, qPAA8, and further narrowed qPAA8 to a 38kb interval.The main results are as follows:1. Through DAB staining to the aborted spike of L-05261, we found that the occurrence of PAA is associated to excess accumulation of hydrogen peroxides (H2O2).2. All the hybrids of 4 cross-combinations including L-05261×9311, L-05261×PA64, L-05261×Balilla and L-05261×IRAT129 appeared PAA phenotypes. On their F2 populations, the percentages of PAA showed a continuous and biased distribution towards non-PAA parents. Both the ratio of 63:1 of PAA plants to non-PAA plants in F2 (L-05261×IRAT129) and the ratio of 7:1 in the BC1F1 are corresponding to the genetic model involving three or more partial dominant genes.4. One hundred and eighty-two individuals from F2 of L-05261×IRAT129 were employed for QTL analysis, and 4 QTLs, designated as qPAA3, qPAA4, qPAA5 and qPAA8 respectively, were detected out, and no significant interaction among them was found. Totally, all 4 QTLs were able to explain 46.32% of observed phenotype variation.5. We carried a gradual linkage analysis to newly developed L-05261×IRAT129 BC1F2 populations, and obtained sequentially three groups of makers RM231, RM1278, RM6058, RM1022; RM1148, RM4085, RM5556 and s5-J9-15, In-c5-9, s5-10-3, which were applied for constructing three sub-populations of qPAA3, qPAA5 and qPAA8.6. Combining the marker selection to stack band diagram analysis, we finally mapped the qPAA8 to 38kb interval between the makers RM22475 and 8-In112. |
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