The Research Of Heterotic Group And Heterosis Model Of The Northern Maize Of China

The utilization of maize heterosis is the earliest, and that popularized all over theworld to achieve the most effective crop.The heterosis group division and use ofmaize is the first crops, the most in-depth study.According to the division of heterosisgroup and advantages mode at home and abroad and its characteristics, combinedwith the northern corn breeding and production practice, according to the principle ofsimple, applicable and effective to the north of maize heterosis group is divided intoReid group, No Reid group and Dom group three advantage group, a triangularheterosis model, referred to as the "three three" theory.Its characteristic is: first, thethree groups constitute independent advantage between groups; Second, the breedingof inbred lines is within groups, the other two groups make a test;Third, the breedingof inbred lines is between two groups, a group of3make a test.This experiment based on triangular heterosis pattern: Reid×Dom No Reid,Reid, No Reid x Dom is on the design of experiment, theory of "three three" validateand discussion, provide theoretical support for the northern corn breeding.The testwill be divided into three model group.Pattern1, on the basis of Reid×No Reid, thebreeding of inbred lines for the system under test, with the DOM group of inbred linesfor the test, equipping hybrids.Mode2, on the basis of Reid by DOM group of thebreeding of inbred lines for the system under test;With No Reid, a group of inbredlines for the test, equipping hybrids.Pattern3, on the basis of No Reid by DOM groupof breeding of inbred lines for the system under test.With Reid, a group of inbred linesfor test, equipping hybrids.In every60000plants/ha ha,75000plants/ha, the densityof90000plants/ha in different conditions, the character on heterosis of yield as index,the heterosis and combining ability.The main results were as follows:With the development of breeding technology，the problem of the narrowgermplasm resources of maize was revealed increasingly, this issue has become oneof the main reasons for restricting the development of our maize breeding andutilization of exotic germplasm, exploring different between groups of germplasmhybrid breeding and improvement by using the method of separation on departmentnew inbred lines, is one of the ways to solve this problem.This experiment according to three heterosis model proposed by zhang shihuang,including Reid, Lancaster and Dom group, according to the three differentkinds of heterosis pattern with Reid×Lancaster, Reid×Dom, Lancaster×Dom (thefollowing abbreviation for mode1,2,3). The basic material was produced throughdoubling methods selection into15new inbred lines, selecting Dom, Lancaster, Reidof15backbone system corresponding to three modes as testers, using the NCIImating design genetic producing75hybrid combinations.Field experiment set60000plant/ha,75000plant/ha and90000plant/ha of density. Field investigationincludes grain weight, plant height, ear position, such as11agronomic characters,collecting data, heterosis and combining ability analysis and correlation analysis ofagronomic traits and yield.The main results were as follows:1. Under the condition of three different density, the75hybrid combinations thatbased on three kinds of mode was analysised heterosis, the results show that the newchoice between inbred lines and test of strong heterosis, has the potential to increaseproduction.Under the60000plant/ha, the highest yield heterosis combination of threemodes is5AD x JD441, advantage value of41%, mode3has4strong heterosiscombination,pattem1does not exist. Under75000plant/ha, the highest yield heterosiscombination of three modes is09B×JD636, heterosis value of38%; Pattern1has6strong advantage combinations, mode2is minimum.Under the90000plant/ha, thehighest yield heterosis combination of three modes is6WC x JD636, heterosis valueof52%; mode2has4strong advantage combinations, mode3is minimum.2. Under the condition of three different density,15inbred lines basing on three kindsof mode to improve breeding0f GCA effect value analysis, the results shows that: inmodel1,inbred lines JD207, JD448yield GCA effect value were higher, and yieldcomponents of GCA effects better.In the mode2, the GCA effects of inbred linesJD441, JD450values were higher,6WC reformed the defects of DOM that is bad.Inmode3, the GCA of yield of inbred lines JD636is higher,8-F reduced the plantheight and increase the ear rowseffectively. Some agronomic traits of inbred linesJD604, JD607also needs further improvement.3. Under the condition of three kinds of density, the75hybrid combinations of threemodes of SCA effect were analysised, the results show that: under the density of60000plants/ha, the number of SCA effect value of yield hybrid combination is37,in mode1,SCA effect values were lower, mode2medium, mode3supreme; Underthe density of75000plants/ha, the number of SCA for yield hybrid combination is40,the proportion of mode2is larger, the SCA effect value of model1and mode3is medium, and the combination of SCA is highest in mode2; Under the density of90000plants/ha the number of yield effect value of SCA is38, in mode2andmode3, the SCA effect value of medium, and combination of SCA is highest in mode1.Through the combination of heterosis, SCA effect value analysis found that the twoconclusions are basically identical.4. In three different density and heterosis mode, path analysis showed that:the largestdirect positive effect to yield is rate of seed, and the the greatest direct native effect toyield is barren length, and with the density increased, the negative effect of barrenlength became more obvious.Therefore, under the condition of different density, therate of seed and barren length are the main factors to effecting yield.