Formation of Doubled Haploid Plants through In Vitro Oryzalin Treatment on Maize Kernels (Zea mays) Estimated Haploid

Abstract

BC2 maize purple kernels estimated haploid were resulted from a cross between Bisma variety with haploid inducer line (3490) by backcross. Chromosome doubling to these kernels was done to produce doubled haploid plants (pure lines). This study was conducted to get an in vitro diploidisation method by oryzalin treatment as a chromosome doubling agent, with concentration of 0, 5, 10, and 15 mM for 24 hours on seeds and root of seedlings. Chromosome analysis on the control of purple kernels showed 66.7% of the seeds was haploid and 33.3% was diploid. Oryzalin treatment affected in doubling the chromosome number from haploid to doubled haploid or from diploid to tetraploid. The higher concentration of oryzalin increased the opportunity of chromosome doubling, but increased death rate. Combination of treatment that is most efficient was 5 mM oryzalin on seedling roots that produced the highest number of doubled haploid plants was found by 71.4% with a low mortality rate by 30%. Increasing of the chromosome number caused the growth of the longer canopy length and more number of leaves and the lower stomata density.