| Available phosphorus deficiency severely in soil is a major limiting factor forrice production. And the non-renewable phosphate rock will be exhausted. Therefore,it is one of the most important issues on investigation and utilization ofphosphorus-deficiency tolerance genes from wild rice, which would provide someimportant theory and practice value direction for development rice variety withphosphorus-deficiency tolerance. And it is a very important strategy for relieving theshortage of phosphorus resources. It has an important significance to high and stableyield of rice.We use Dongxiang wild rice as the donor parent, and Xieqingzao B as recurrentparent to construct BC1F10Backcross inbred lines, which were used to Sereening ofseedling tolerance to low phosphorus Rice, QTL mapping and cytological observationon the tolerance to Low-phosphorus introgression lines. The control lines includedDalidao (tolerance to low phosphorus), Huzhanqi (low-phosphorus-sensitive) and theparents. The main findings are:1.The screening results of tolerance to low phosphorus varieties: Use234varieties with sand quartz culture of BC1F10backcross inbred lines of Dongxiang wildrice, with1/2MS culture solution and low concentration phosphorus stress at the twoleaves a heart, after Cultured for28days, the determination of seedling height,maximum root length, number of roots, shoot fresh weight and so on10relative toPhenotypic data,17varieties included7,26,35,64,66,67,107,121,123,169,171and soon of tolerance to low phosphorus was preliminary screening, which screeningtolerance to low phosphorous varieties through construct composite index of using themean and standard deviation.2. The results of QTL mapping show that a total of22additive QTLs fortolerance to low phosphorus related traits were detected by using CIM method, whichdistributed through chromosome2,3,4,8. Among them,1QTL was for RelativeMaxumum Root Length,2QTL was for Relative Stem and Leaf Fresh Weight,3QTLwas for Relative Stem and Leaf Dry Weight,2QTL was for Relative Root FreshWeight,6QTL was for Relative Root Dry Weight,4QTL was for Relative Total DryWeight,3QTL was for Relative Total Biomass,1QTL was for Relative Leaf Age. It explaining8.92%~47.90%of phenotypic variance, the value of additive effect is15.27%~85.67%, the multiple overlapping QTLs were detected at the region ofRM29-RG157and RG157-RM262on chromosome2, RG510-RZ251andRM218-RZ313on chromosome3, the contribution rate and the value of effect wasrelatively large in which control rice tolerance to low phosphorus of the major QTLsmay exist in these overlapping regions.3. The result of meiotic behavior observation: the rate of pollen mother cells(PMC) with normal meiotic behavior in the IL7and IL169was to94.12%, the rates ofpollen germination in vitro were (83.01±2.78)%and (81.94±1.70)%, respectively.There were no significant differences between the cold-tolerant introgression linesand their parents. At Diakinesis, the low frequency of abnormal chromosome behaviorwas observed in IL7and IL169, such as univalent; rod bivalent; trivalent andunivalent, and lagging chromosomes exist at anaphase Ⅰ, which suggested that therewere genetic exchange and recombination between cultivated rice and common wildrice. In addition, a small number of nucleoli was observed at pachytene, while theirparents only had one nucleolus. Statistics chromosome configuration of IL7andIL169, IL7for0.23Ⅰ+11.85Ⅱ+0.01Ⅲ+0.01IV, IL169for0.41Ⅰ+11.72Ⅱ+0.01Ⅲ+0.01IV, It show that the chromosome configuration of two tolerance to lowphosphorus introgression lines also exist some differences, these special chromosomeconfiguration might be have an impact to the fertility of male and female gametes... |
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