Genetic Analysis Of Winter Wheat Varieties And Their Super Higher Yield Characters In Hebei Province

In China, the harvest area and production of wheat is next to those of rice, and ranksthe second in all crops. In Hebei Province, the harvest area of wheat is more than230million ha each year, and the production ranks after Henan and Shandong Province.Enhancement of wheat production capacity in Hebei Province is of great importance inensuring national food security in China. Water resource is very limited in Hebei Province,especially the precipitation is less in the period of wheat growth, which can not meet thedemand of wheat. It is, therefore, of great significance to determine the genetic diversityand characteristics of winter wheat variety with super high yield in broadening the geneticdiversity of wheat germplasm, increasing breeding level of drought resistance andinnovating irrigation and N application of different types of wheat varieties.In this study, genetic diversity of156winter wheat varieties authorized in HebeiProvince from1976to2013were analyzed by pedigree analysis and genetic contributionratio of wheat backbone parents. Drought resistance and genetic diversity of85winterwheat varieties authorized in Hebei Province from1997to2007were studied throughdrought resistance coefficient, drought resistance index and SSR markers. Winter wheatvarieties of high nitrogen efficiency were screened under three water-nitrogen regimes, i.e.,N300kg/ha+twice spring irrigation, N240kg/ha+twice spring irrigation, and N180kg/ha+once spring irrigation through multi-site experiments carried out in the wheat fieldsof super highly yielding demonstration in counties involved in Hebei area of The NationalScience and Technology Project for Food Production. The results were as follows:1. Genetic contribution ratio of backbone parents and key breeding parents of winterwheat varieties authorized in Hebei Province were explicated. Based on geneticcontribution ratio of backbone parents to modern varieties, it was concluded that,11wheatbackbone parents from the species Triticum aestivum, including Mazhamai/Biyumai, weredetermined to be the main progenitors of winter wheat varieties authorized in HebeiProvince. The contribution ratio of the11backbone parents in the order from high to lowwere Mazhamai/Biyumai, Early Piemium, Lovering10, Orofen=Xiannong39,Triumph/Yanda1817, Aapopa, Fengchan3, Abbondaza, Linzhangmai and Taigu genic malesterile wheat, respectively.Ten wheat varieties authorized in Hebei Province, Jinfeng1, Shixin733, Taishan5, Jimai36, Jimai30, Jimai32, Jimai38, Shi4185, Gaoyou8901and Han6172were key parentsin wheat breeding of this region since1949. According to the agronomic traits of these keyparents, wheat breeding objective in Hebei Province was determined and should closelycombine the ecological conditions during wheat growing season, especially pay attentionto multi-spike, lodging resistance, high yield, drought resistance, salt tolerance, and rustresistance.2. Drought resistance indices of winter wheat varieties authorized in Hebei Provincewere screened, and breeding direction of drought resistance and high yield was clarified. Itwas found that the grain length and specific gravity were positively correlated to high yieldand drought resistance of wheat varieties significantly. Grain setting rate and grain lengthin the condition of drought were reliable traits for drought resistance identification ofwinter wheat varieties. A majority of winter wheat varieties authorized in Hebei Provinceshowed higher yield under irrigation, but their drought resistance need to be improved. Theimprovement of spikes per plant, grains per spike and the length of flag leaf underirrigation were a breeding approach for increasing wheat yield, but the increase of spikesper plant and grains per spike, and shorter flag leaves become a breeding direction forincreasing yield under drought. Genetic basis of wheat germplasms with drought resistancewas narrow in Hebei Province. Broadening genetic abundance of drought resistancegermplasm was, therefore, very important for high yield and drought resistance breeding ofwheat. Introduction, collection and creation of elite germplasm with high yield and droughtresistance need to be enhanced from now on.3. Genetic diversity of87tested winter wheat varieties was abundant using SSRmolecular markers. The effective number of alleles for each locus (Ne) varied from1.644to20.333, with an average of4.708. Shannon-Weiner index (SI) ranged from0.148to1.102and averaged0.544. These indicated that genetic diversity of tested varieties was lowbased on SSR markers. The genetic similarity coefficients (GS) varied from0.184to0.899,with an average of0.418. That means that the genetic variation of the varieties from HebeiProvince was higher than those from other Provinces. The GS averages were differentamong the varieties released from different breeders. The UPGMA cluster indicated thatthe genetic difference of the varieties bred by Shijiazhuang New Wheat Variety andTechnology Research Institute was highly differ from those bred by other breeders. So, tointroduce the germplasms with different genetic background and charactercomplementation for parent selection should be pay attention by breeders in order to breedmore elite wheat varieties.4. The characteristics of super higher yield winter wheat varieties in Hebei Provincewere clarified. Multi-spike variety was a principal type for increasing winter wheat yield.The yield components were764.7spikes per m2,34.5grains per spike, and1000grainweight41.3g. Characteristics of population culms comprised about361.7seedings per m2, 1084.1culms pre m2before over-winter, with a maximum1465.2culms pre m2,53.6%ofspiking ratio,71.2%of spikes accounting for before winter culms. And47.3%of spikescame from main shoots, and53.7%from tillers. Leaf area index characteristics includedabout0.88before winter,1.2at erecting stage,6.04at jointing,7.53at booting, and5.54atanthesis stage. The plant height showed16.2cm before winter,18.8cm aterecting,42.0cmat jointing,75.9cm at booting, and75.9cm at anthesis stage. Characteristics ofadventitious roots per plant were about2.5pre-winter,20.2at jointing, and29.2at anthesisstage.5. Appropriate irrigation and N application of winter wheat with super higher yieldwere explicated, and super higher yield winter wheat varieties were screened. Averageaccumulation of dry matter and average grain weight of winter wheat were the highest inthe treatment of N240kg/ha+twice spring irrigation. This treatment was the best measurefor coordinating vegetative and reproductive growth of winter wheat and achieving highergrain yield. N efficiency of winter wheat had a range in N application, and the differenceexisted among different varieties. Strong gluten winter wheat variety Gaoyou2018hadhigher efficiency of N application than other winter wheat varieties. Henong200andshiyou20, Jimai585and Henong826, and Yingbo700displayed higher efficiency of Napplication in all nitrogen application rate, higher nitrogen application rate, and lowernitrogen application rate, respectively.