Molecular identification of plants regenerated from somatic hybridization between rice and apomictic Panicum

We attempted to introduce apomictic gene(s)into rice via somatic hybridization by usingapomictic Panicum maximum Jacq.as thedonor of apomictic gene(s).Protoplasts of rice derived from suspen-sion cells were inactivated with indoacetamide(IOA)and protoplasts of Panicum maximum

Genetic Diversity Analysis of <i>Cotoneaster schantungensis</i>Klotz. Using SRAP Marker

In order to detect the genetic relationship of different Cotoneaster schantungensis natural populations, 16 samples were selected for genetic diversity analysis based on SRAP markers. Twelve pairs primers were selected out, 93 bands were amplified, of which 91 bands (97.85%) were polymorphic. At species level, the average value of Nei’s genetic diversity (H) was 0.2213, Shannon’s information index (I) was 0.3596, whereas at population level, they were 0.1955, 0.3121, the percentage of polymorphic loci was 75.27%. The genetic differentiation coefficient in populations (Gst) was 0.0788, gene flow Nm was 5.8467, indicating that there was 7.88% of the variation among populations and 92.12% of the variance within populations and the variation within populations was relatively high. These results indicate that C. schantungensis has high genetic diversity and low differentiation among populations. Although most Cotoneaster species are apomictic, C. schantungensis, however, may be an exception.

A strategy for generating rice apomixis by gene editing

Apomixis is an asexual reproduction way of plants that can produce clonal offspring through seeds.In this study,we introduced apomixis into rice(Oryza sativa)by mutating OsSPO11-1,OsREC8,OsOSD1,and OsMATL through a CRISPR/Cas9 system.The quadruple mutant showed a transformation from meiosis to mitosis and produced clonal diploid gametes.With mutated Osmatl,which gives rise to haploid induction in plants,the quadruple mutant is expected to be able to be produced apomictic diploid offspring.We named this quadruple mutant as AOP(Apomictic Offspring Producer)for its ability to produce apomictic offspring.

Progress of Apple Rootstock Breeding and Its Use

Apple rootstock breeding has achieved great progress worldwide.In this review,we first summarize the rootstock breeding targets and utilization in main apple-producing countries.Furthermore,we discuss the focus and important research areas of apple rootstock breeding through five aspects:parent selection and setting of crosses,target genes and marker-assisted breeding,root configuration-guided breeding,apomictic resource utilization,and the application of genetic engineering.Finally,we propose an apple rootstock division plan for China,which has a large potential to provide guidance for apple rootstock breeding and utilization in different apple-producing areas of China.

Floral sex allocation and reproductive success within inflorescences of Hosta ventricosa, a pseudogamous apomict

Aims Within inflorescences of sexually reproducing hermaphrodites,the production of ovules,fruits and seeds commonly declines from basal(early-opening)to distal(late-opening)flowers,while pol-len production remains constant or only changes slightly,with the result that distal(late-opening)flowers become functionally male.However,few empirical studies have specifically examined whether or not changes in allocation to pollen production actually lead to changes in the number of seeds sired,a more direct measure of male fitness.in pseudogamous apomicts,fitness depends on the number of seeds produced;thus,a contrasting pattern of variation in the pollen-to-ovule(P/o)ratio within inflorescences might be expected.Methods We investigated floral sex allocation and reproductive success within racemes of Hosta ventricosa,a pseudogamous apomictic hermaphrodite possessing flowers that open acropetally.We quan-tified variations in pollen number,ovule number,the P/o ratio and fruit and seed production,from 2007 to 2011,among flowers within racemes of four populations of H.ventricosa in southwest China.Ecological causes for fruit and seed production were evaluated by observing patterns of pollen deposition,flower removal and sup-plemental pollination.Important Findings Pollen number,ovule number and the P/o ratio declined from basal-to-distal positions in all sampled populations(years).Fruit and seed production decreased distally in most populations(years).low fruit and seed set of distal flowers was not due to pollen limitation because pollen deposition never declined distally and the low fruit and seed set of distal flowers remained even after supplementary pollination was provided.The flower-removal experiment indicated that inter-fruit competition for resources among flowers was common.The low P/o ratio of distal flowers in H.ventricosa might be favored because they were unable to obtain fitness by donat-ing pollen and siring seeds on other plants.our study may help to understand the adaptive significance of sex allocation among flow-ers within inflorescences of sexually reproducing hermaphrodites.