A Key Technology Of DH Breeding And Genetic Analysis With Different Types Of DH Lines

DH Technology is a key method to accelerate the breeding process and get excellent inbred line quickly in maize breeding. But the low inducing rate and doubling rate are the two main limitations. Therefore, select the higher inducing rate line and improve the doubling technology are good solutions for the utilization in maize breeding widely. The acquired DH lines which have not been selected by natural condition, so it is necessary in order to test in a different ecological zone. This study does deep research in the impact factors of haploid inducing rate, haploid doubling rate, and the adaptability of DH lines in a different ecological zone.It is difficult to select suitable lines because the confused heterotic groups in China, Moreover the US heterotic groups have not been integrated into the Chinese germplasm. This study simplifies the heterotic groups assortment for that was divided into Reid, Non Reid, DOM 3 dominant group. Taking the DH lines bred as the material, according to " triangle " pattern to design the trial. It is estimated that providing a new method for maize neurotic groups assortment and heterosis utilization patterns in Chinese maize breeding.The results were as followed:(1) The acquired line(F6-RWS)-5-8-3-1-1 which selected from RWS×CAUHOI1 1 has the highest inducing rate. The value is 17.4%. According to the marker expression and tassel length classification, the ranking is 5 and 3. The lines selected from two induced lines have higher inducing rate. For example, the inducing rate of 20 lines which selected from F6-RWS was over 10%.F6-RWS in F6 induced breeding lines induced by the mean rate of up to 11.6%. It is found that(CAUHOI1×PHB1M) can be used in improving the offspring’s lodging resistance, plant height, powder loosing. It is suitable for the hybridization induced in the field produce, but the inducing rate is depressed, 0.9%~3.9%. But the combination of plant with CAUHOI backcross F2 generation induced by ability, their offspring inducing rate was obviously improved for rate is 5.6%~10.5%, powder loosing earlier, plant height is suitable. In order to obtain the excellent inbred lines with high inducing rate, which can use the second circle method from the non induced line non induced line, and combining with the high value parent backcross. The obtained line can be used in large scale production of hybrid induction. The backcross method can use in the improvement of agronomic traits of the best inducer.(2) The average of inducer F1 hybrids inducing rate is 10.9%, the mean inducing rate of maternal and paternal inducer, respectively, 14.9% and 7.7%. F1 generation of inducing rate lower than the high value parent, higher than minimal value parent, but F1 generation of inducing rate is lower than the average of parent inducing rate. Induction obvious heterosis, heterosis mean of 97.4%, mean parent heterosis-2.6% heterobeltiosis mean of-34.7%.(3) The heterosis pattern of J111×J112 is Non Reid×Non Reid. The inducing rate and doubling rate is the highest in Yushu. Baicheng and Changchun, indicating that Non Reid can be easily be induced as the haploid. The inducing rate, natural doubling rate and APM doubling rate in Changchun was significantly higher than that of Yushu and Baicheng, haploid natural doubling rate and APM doubling rate in Yushu was higher than the location of Baicheng.(4) High density resistance of DH lines and EH lines had the same curve in different plant density. But the main index from the perspective of empty bar rate, ASI, the double ear rate, grain yield per plant, yield the density tolerance, high density tolerance, this study indicated that EH population is better than DH population in high density tolerance. It is difficult to obtain the EH line, so expanding the EH line production is necessary that can make that effective for use in the maize breeding.(5) In mode 1(Reid×Non Reid), mode 2(Reid DOM) and mode 3(Non Reid×DOM) of three kinds of heterosis pattern, it exists that heterobeltiosis in DH line and EH line. The positive numbers of GCA(general combining ability) of yield per plant are 13 in mode 3, the GCA mean value is 7.6. The positive numbers of GCA value are 12 in mode 2, the GCA mean value is 4.84. The positive numbers of GCA value are 8 in mode 1, GCA mean value is 2.86. The positive number of SCA(special combining ability) value for mode 1, mode 2, mode 3 are 46, 50, 48, respectively. the mode 2 for improving the EH can get high yield potential. The hybrid pattern is Reid×DOM inbred lines with Non Reid group are better.