Maternal karyogene and cytoplasmic genotype affect the induction efficiency of doubled haploid inducer in Brassica napus

Background Artificial synthesis of octoploid rapeseed double haploid (DH) induction lines Y3380 and Y3560 was made possible by interspecific hybridization and genome doubling techniques. Production of pure lines by DH induction provides a new way to achieve homozygosity earlier in B.napus. Previously, the mechanism of induction, and whether the induction has obvious maternal genotypic differences or not, are not known so far. Results In this study, different karyogene and cytoplasmic genotype of B.napus were pollinated with the previously reported DH inducers e.g. Y3380 and Y3560. Our study presents a fine comparison of different cytoplasmic genotypes hybridization to unravel the mechanism of DH induction. Ploidy identification, fertility and SSR marker analysis of induced F1 generation, revealed that ploidy and phenotype of the induced F1 plants were consistent with that type of maternal, rather than paternal parent. The SNP chip analysis revealed that induction efficiency of DH inducers were affected by the karyogene when the maternal cytoplasmic genotypes were the same. However, DH induction efficiency was also affected by cytoplasmic genotype when the karyogenes were same, and the offspring of the ogura cytoplasm showed high frequency inducer gene hybridization or low-frequency infiltration. Conclusion The induction effect is influenced by the interaction between maternal karyogene and cytoplasmic genotype, and the results from the partial hybridization of progeny chromosomes indicate that the induction process may be attributed to the selective elimination of paternal chromosome. This study provides a basis for exploring the mechanism of DH inducer in B.napus, and provides new insights for utilization of inducers in molecular breeding.

KARAKTERISASI PISANG REJANG TETRAPLOID HASIL INDUKSI DENGAN ORYZALIN

Triploid banana cultivar is the most desirable cultivar in banana industry because of its higher yield compared to its diploid cultivar. The triploid cultivar can be produced by crossing tetraploid with diploid cultivar. However, tetraploid banana cultivar is rarely existed naturally. Induced tetraploid of Pisang Rejang was produced using oryzalin. The present research was conducted to characterize tetraploid Pisang Rejang (Musa acuminata, AAAA genome) induced by in-vitro oryzalin treatment from diploid Pisang Rejang. Ploidy level, molecular and morphotaxonomic characters were observed. Ploidy identification of induced Pisang Rejang was conducted using Flowcytometer. Molecular characterization was done using RAPD and ISSR markers. Morphology characters were observed based on UPOV (2010). The results showed that tetraploid plants have similar genetic properties with their diploid controls as shown by genetic identity of 0.9901 – 0.9935. The tetraploids were differed from their diploid plants in plan habit and diameter of fruit. The tetraploid plants produce fewer suckers, drooping leaves and broader fruits compared to its diploid control.

Ploidy identification of doubled chromosome number plants in Viola × wittrockiana Gams. M 1-generation

The aim of this study was to develop a protocol for production of polyploid M1-generation plants of Viola × wittrockiana Gams. Two variants of colchicine treatment were compared for their efficiency. Early detection of novel ploidy levels was achieved by screening of stomata size, leaf index value (leaf blade length/width), and other morphological characteristics of the M1-generation. Secondary screening for novel ploidy levels was performed by flow cytometry (FCM). Hexadecaploid, aneuploid, and mixoploid plants were successfully identified by FCM.