Natural restoration and diploidization of haploids in maize

Abstract

AbstractDouble‐haploid breeding technology is the most efficient breeding technique for maize (Zea mays L.). In this study, we used haploids produced from 12 maize hybrids and 13 inbred lines induced by Jikeyu115, calculated natural doubling rates of the haploids, and studied male and female fertility. The results showed that the recovery degrees of male inflorescence fertility of 25 different haploids were significantly different. The power rates of male tassels varied from 0.81 to 11.48% (average, 4.42%). The degree of fertility recovery of male ear was much lower than that of female ear (60.83%), which was the limiting factor of self‐fruiting of haploid. Summer sowing at a location that has a large daytime/night‐time temperature difference may be beneficial to fertility recovery of haploid male panicles and to the loose pollen rate, with an average of 9.80%. In the natural state, detecting the cells by flow cytometer, we found that most of somatic cells of haploid male fertile plants are haploid state (1C), and there is a ploidy chimerism including haploid and diploid cells in a few somatic cells. About 1.4% aneuploidy (1.5C) is detected. In the practice of haploid breeding, materials with strong male fertility recovery ability can be selected to carry out haploid breeding, and an environment suitable for male panicle fertility restoration can be selected for haploid natural doubling.