• ZHONGLI HU

Articles written in Journal of Genetics

• Quantitative trait loci controlling Cu, Ca, Zn, Mn and Fe content in rice grains

• Genomewide mapping reveals a combination of different genetic effects causing the genetic basis of heterosis in two elite rice hybrids

North Carolina design III (NCIII) is one of the most powerful and widely used mating designs for understanding the genetic basis of heterosis. However, the quantitative trait mapping (QTL) conducted in previous studies with this design was mainly based on analysis of variance (ANOVA), composite interval or multiple interval mapping methods. These methodologies could not investigate all kinds of genetic effects, especially epistatic effects, simultaneously on the whole genome. In this study, with a statistical method for mapping epistatic QTL associated with heterosis using the recombinant inbred line (RIL)-based NCIII design, we conducted QTL mapping for nine agronomic traits of two elite hybrids to characterize the mode of gene action contributing to heterosis on a whole genomewide scale. In total, 23 main-effect QTL (M-QTL) and 23 digenic interactions in IJ (indica × japonica) hybrids, 11 M-QTL and 82 digenic interactions in II (indica × indica) hybrid QTLs were identified in the present study. The variation explained by individual M-QTL or interactions ranged from 2.3 to 11.0%. The number of digenic interactions and the total variation explained by interactions of each trait were larger than those of M-QTL. The augmented genetic effect ratio of most M-QTL and digenic interactions in (L1–L2) data of two backcross populations (L1 and L2) showed complete dominance or overdominance, and in (L1 + L2) data showed an additive effect. Our results indicated that the dominance, overdominance and epistatic effect were important in conditioning the genetic basis of heterosis of the two elite hybrids. The relative contributions of the genetic components varied with traits and the genetic basis of the two hybrids was different.

• First report on DNA content of three species of Amorphophallus

The Amorphophallus genus is a perennial herb which belongs to the family Araceae. There are more than 170 species in this genus, which is widely distributed in tropical and subtropical areas. As a kind of food and medicine Amorphophallus has been used for more than 2000 years in China. Because of the high content of konjac glucomannan (KGM) and dietary fiber, it has attracted more attention worldwide. In this article, the DNA contents of A. konjac, A. albus and A. bulbifer in China, A. albus, A. paeoniifolius and A. muelleri in Indonesia were estimated by using flow cytometry. In the samples of China, the DNA contents were 12.95 ± 0.73 pg/2C in A. konjac, 10.51 ± 0.05 pg/2C in A. albus and 17.61 pg/2C in A. bulbifer, and for Indonesia, 14.16 ± 0.48 pg/2C in A. albus (flowering), 8.49 ± 0.2 pg/2C in A. paeoniifolius and 17.84 ± 1.46 pg/2C in A. muelleri were used. Interspecific variation was found significantly (P<0.01), suggesting that DNA content might be a parameter that can be used to differentiate the species. Intraspecific variation has also been found significantly (P<0.01), whether in the same region or between two regions. As far as we know, this is the first report ongenome size estimation of the A. konjac, A. albus and A. muelleri using flow cytometry. Understanding the genome size of Amorphophallus species will help to sequence the genome and analyse the genetic diversity, evolutionary relationship and geographical variation pattern of Amorphophallus species.

• A mixed ploidy natural population of Amorphophallus muelleri provides an opportunity to trace the evolution of Amorphophallus karyotype

Amorphophallus, a perennial herb belongs to the family Araceae, and is widely distributed in Asia and Africa. As anagricultural crop, it has been cultivated and consumed for ${\sim}$ 2000 years in China. Previous studies have found that there are chromosomenumber and ploidy changes in this genus, but there are a few reports on the evolution of different karyotypes. For this study, we collected 37samples of a wild population of Amorphophallus muelleri from Myanmar and analysed their karyotypes. The karyotype analysis showedthat it is a population with mixed chromosome numbers and ploidy, with four karyotypes of 2n = 24, 26, 28 and 39. Combining the resultsof this study with previous literature, we speculate that karyotypes with 2n = 26 may be the common ancestor, and further the other threekaryotypes were evolved from this by various ways. As far as we know, this is the first attempt to put forward the hypothesis of theevolution of those four karyotypes together. On the other hand, by using inter-simple sequence repeat marker-based unweighted pair groupmethod with arithmetic mean cluster analysis, we found that these individuals of four karyotypes can be divided into four correspondingcategories, indicating that they have been differentiated at the genome, providing a theoretical basis for future use of these wild germplasmresources.

• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019