Genetic Analysis Of Main Traits And Research On Traits Improvement For Big Ears Wheat Xinong 9814

Wheat is an important food grain in our country, improving its yield has importmant role in ensuring chinese food security. Varieties is the main factors for yield increasing. Increasing kernel weight is one of the major ways to increase wheat yield, when productive spikes of the population reached a limit. So, it is emphasized by the breeders that breeding high or super-high yielding wheat varieties with big ears.Xinong 9814 is a wheat variety with big ears, it was found in the progeny from the hybrid between Xinong 1718 and Linhan 957. Most of characters of it are well. Kernel weight is more than 2.5g. But its leaf area is larger, and the tillers has lower rate growing into ears.These disadvantages lead to its yield is normal. In order to increasing its yield potential significantly, Xinong 9814 is needed genetic improved, appropriatly reduced leaf area, increased the rating of tiller growing into ears. Breeding varieties with small(middle) leaves,more tillers(ears) and big spikes, using the advantage of higher single grain weight and more spike number, increase yield potential singificantly. In order to effectivly improve Xinong 9814, in this paper, major characters of it were analyzed and studied, expecting providing a basis for its improvement. The result of research is as follows:1. GISH,SCAR,SSR and A-PAGE analysis revealed that Xinong9814 was a wheat-rye 1BL/1RS translocation line.2. Compared with its parents, Xinong 9814 has biger spike, more grain number. Kernal weight per ear of it is exceeding that of the parents.But the tiller number(TN) and effective spike number per plant(ESP) of it tend to low parent, its leaf area tend to high parent. These disadvantages result in its leaves larger, tiller number and spike number fewer. So, Xinong 953 and Xinong 9718 are selected as improvement parents for Xinong 9814.Improvement parents has smaller leaves, more tiller number, and higher earing rate, which is advantage to improve Xinong 9814. But their lower ear weight is against to keep higher ear weight of Xinong 9814. Through the extension of generation population and coordination oriented selection for target characters, a variety with midele leaves and more tillers has been breeded, the kernel weight per ear of it closed to that of Xinong 9814.3. Correlation analysis on main agronomic chatacters of Xinong 9814 showed that increasing tiller capability of Xinong 9814, will be hepful to increase effective spike number per plant and spikelet number. Effective spike number per plant, spike length and spikelet number were positive correction with leaf length, leaf width and leaf area, reducing leaf area of Xinong 9814 possible lead to the ear weight reduced and effective spike number per plant decreased. Effective spike number per plant can be improved when tilling capability be improved. The study of source-sink coordination of big spike wheat have shown wheat with big spike have more source and sink, moreover, source was relative surplus.Through appropriatly reducing leaf area and paying attention to improvement selecting of leaf and photosynthetic efficiency, and increasing light penetration of population and photosynthetic efficiency, it is possible for breeding a varieties with smaller leaf, big spike and more spikes.4. Xinong 9814 integrated the genetic characteristics of both parents on gliadin and glutenin levels. Xinong 9814 has 1, 7+9,5+12 subunits, and is 2- level strong gluten wheat. Using 7+8 subunit of the improvement patents replaced 7+9 of Xinong 9814 promoted quality improvement of it.5. There is largely genetic difference on molecular level between Xinong 9814 and its improvement parents, Xinong 953 and Xinong 9718. So widly variant types can be produced by gene recombination in hybrid progenies. This can provide richy genetic variation for selecting traits.6. Two crosses Xinong 9814×Xinong 953(cross) and Xinong 9814×Xinong 9718(cross) and their derived genetations (F1, F2), were used to analyze the inheritance of main characters by the major gene plus polygene mixed inheritance model. The result showed that the genetics of the traits, such as tiller number(TN), effective spike number per plant(ESP), spike length(SP), flag leaf width(FLW), were according to two major genes+polygene mixed genetic model; that of flag leaf length(FLL) for two crossed were polygene model without major genes; The model of flag leaf area(FLA) in crossⅠwas two major genes plus polygene model, while that for crossⅡwas polygene model without major gene.7. The estimate of correlation of 7 main characters proved, increasing tiller capability can contribute to ESP, SL and SN creasing; increasing ESP also enhance SL and SN. ESP and SL were positive correlated with FLL, FLW and FLA, but the correlation coefficent is smaller, so it is possible that breaking the correlation to make smaller leaves and more spikes combination.The correlation coefficent of Spikelet number with FLL, FLW and FLA is larger, but SN is dispersive distribution in the F2 population,so it is possible for using genetic recombination to make smaller leaves, more spikes and biger spikes cmobination.8. The gene related to TN and ESP were mapped in Xgwm495-Xgwm113 interval on chromosome 4B, away 2.2 cM from Xgwm113, explained 34.6% of phenotypic variation for TN, and 5.9% for ESP. The QTLs of ESP and TN showed partially dominant and additive effects, respectively. The nagative value indicated that the QTLs was from Xinong 953 increasing ESP and TN. QTL of SN was mapped on chromosome 2B. QTLs of SN and FLW were mapped on chromosome 2B. the SN gene was mapped location away 4.3 from Xwmc441, explained 7.1% of phenotypic variation.Additive and dominance effects were positive for SN, and the QTL showed additive effect, which was derived from the parent Xinong 9814. The FLW gene was mapped on Xwmc477 location, explained 7.1% of phenotypic variation. Additive effect was positive which was derived from Xinong 9814 and dominance effect was dispositive which was derived from Xinong 953. The QTL of FLW showed partially dominant. QTLs of SL and FLL were detected using single marker analysis at significance levels 5% or 1%.