Evaluation Of Ecological Adaptability And Analysis Of Genetic Diversity Of New Maize(Zea Mays L.) Haploid Inducers

Maize haploid inducer could induce the female to produce haploid through hybridization. The haplois produced were doubled to obtain homozygous diploid by natural or artificial methods, then we select the excellent maize inbred lines from them, thus greatly shortening the breeding period and speed up the breeding process. Therefore, the maize haploid inducer has been more and more popular. In view of existing maize haploid inducer of narrow genetic basis and poor flexibility in Sichuan, we introduced a series of excellent maize germplasm resources to build a suitable and excellent the new maize haploid inducer. In this experiment, with 39 maize haploid inducers being male parents (9 introduced inducers and 30 improved inducers) and 6 maize hybrids being female parents (Shengnuo 11, Meiyu 3, Meiyu 16, Chengdan 30 and Mol7×B73 F1, respectively), we surveyed their agronomic traits, induction rate, pest resistance and lodging, and analyzed the genetic diversity by using SSR molecular markers, to evaluate the ecological adaptability of inducers in Sichuan in order to select the excellent maize haploid inducers with high rate of haploid inducer and provide some theoretical guidance for Maize Haploid breeding in Sichuan. The results are as follows:1. Different Maize haploid inducer has significant difference in agronomic traits. The variation coefficients of induction rate, bald tip length, lodging rate and pollen amount is greater than 60%, and of seed setting rate is greater than 30%. Average induction rate of thirty-nine haploid inducers ranged from 0.10% to 5.65% with an average being 2.14%, among which YD-28 had the highest induction rate and YD-17 had the lowest. Induction rate of the majority of inducers were ranged from 1% to 3%.2. The ability of same inducers induce different female parents producing haploid was different. The proportion of Chengdan 30 induced by thirty-nine maize haploid inducers was 2.79% in average, which was significantly (P<0.05) higher than the other 4 females. The proportion of Meiyu 3 induced by thirty-nine maize haploid inducers was 1.43% in average, which was extremely significantly (P<0.01) lower than the other 4 females. Induction rate is a function of each parent’s results, affected by both genotypes and less affected by the environment. The induction rates of different induction lines to the same female parent were different, and so the situation of same inducer to different female parents. Therefore, in order to get the higher induction effects we should choose the right combination of inducer and female parent.3. Results of correlation analysis on agronomic traits showed that the induction rate had a significant negative correlation with seed setting rate, and seed setting rate had a significantly positive correlation with the rows of tassel, and male branch number had a significant positive correlation with the relative amount of pollen, and tassel height and plant height was positively correlated. Based on the related traits in selection, we can improve the efficiency of induced breeding.4. Part of introduced inducers had a good ecological adaptability in Sichuan. After importing maize germplasm resource into the old inducers, most of modified induction lines has been improved. Among the self induced lines YD-10, YD-12, YD-17, YD-25, YD-27, YD-28, YD-31, YD-33, YD-34, YD-35 and introduced line YD-39 could adjust the Sichuan ecological environment better, while YD-18, YD-19, YD-20, YD-21 had a low ecological adaptability.5.75 pairs of polymorphic SSR primers selected from over 100 pairs of primers which covered the entire maize genomes. A total of 239 polymorphic bands were detected 39 inducer samples, and per primer had 3.18 polymorphic alleles in average with the average PIC value being 0.695, which indicated that these maize inducers had abundant genetic diversity.39 maize haploid inducers were divided into 2 groups and 9subgroups by SSR cluster analysis. The same pedigree materials were mostly clustered to the same subgroup, which consistented with the genetic genealogy on the whole.