Assessment of genetic effects on important breeding traits in reciprocal DH populations of winter oilseed rape (Brassica napus L.)

Here we present a study on the genetic effects of agronomic and seed quality traits in double haploid （DH） populations, which were developed by microspore culture from reciprocal F1 hybrids produced between cultivar Californium and DH W-15. Each of the populations consisted of 25 DH lines. The field experiments were conducted in a randomized complete block design with three replications during three growing seasons. Field observations were recorded on seed yield and its structure： the number of branches and pods per plant, the number of seeds per pod, the 1 000-seed weight, the content of fat in the seeds, and three unsaturated fatty acids （oleic, linoleic, linolenic） in the seed oil. In order to investigate the influence of cross direction on the studied traits, parental effects were evaluated on the basis of differences between reciprocal DH populations. The maternal effect was revealed on the number of seeds per pod and the effect of the paternal form on linolenic acid content. The occurrence of transgression effects also depended on the direction of crossing and this was particularly noticeable in terms of the number of seeds per pod. The use of multivariate statistical methods allowed for the simultaneous characterization and grouping of tested lines in terms of several traits. Graphic images of the distribution of DH lines in the space of the two first canonical variates showed a great variation between the two reciprocal populations, both in terms of yield and its components, as well as fat and those unsaturated fatty acids.

Breeding of High Yield,High Quality and Disease-Resistant Hybrid Cotton Varieties Hanza 160 and Hanza 1692

The hybrid cotton varieties of Hanza 160 and Hanza 1692 were bred by reciprocal crosses between Han 5158 and Han 333 in Hainan and Hebei for several years. Both varieties had the characters of high yield, high quality and disease resistance. Hanza 160 and Hanza 1692 were approved by Hebei Crop Variety Approval Committee in 2013 and 2016, respectively.

Combining ability and heterosis analysis over two environments in a diallel cross of three families of the clam Meretrix meretrix

A 3×3 complete diallel cross comprising three families of the clam Meretrix meretrix（P1, P2 and P3） was used to determine the combining ability of parental families and heterosis of F1 under indoor and openair environments for growth traits. Analysis of variance for shell length and whole body weight indicated highly significant cross effects, environment effects and the interaction of cross by environment. General combining ability（GCA） and specific combing ability exhibited great variation among crosses and between two environments. Pooled over environments, P2 was the top combiner among the three parental families for both traits studied. The cross of P1 and P3 had the highest SCA. Additionally, significant reciprocal effects were observed. For individual environment, about half of the crossbred combinations showed favorable Mid-parent heterosis（MPH）（〉1%） for the shell length and whole body weight. Our data has shown that non-additive genetic and reciprocal effects constituted the major sources of genetic variation for both shell length and whole body weight, which indicates that crossbreeding among selective families could further explore the heterotic effects.

Gold: A Unique Pigmentation Defective Laboratory Strain of the Lady Beetle

A laboratory colony of Coleomegilla maculata (De Geer) was selected for a novel phenotypic color trait. The phenotype was paler in color than the wild type, although not as pale as a previously described mutant strain, yellow (ye), and retained dark pigmentation in the eyes. This selected strain was named gold. Mendelian breeding experiments indicate a recessive biallelic inheritance. The strain has decreased fitness characteristics based on measurements of egg production and pupa size.

Whole-genome single nucleotide polymorphism and mating compatibility studies reveal the presence of distinct species in sub-Saharan Africa Bemisia tabaci whiteflies

In sub-Saharan Africa cassava growing areas,two members of the Bemisia tabaci species complex termed sub-Saharan Africa 1(SSA1)and SSA2 have been reported as the prevalent whiteflies associated with the spread of viruses that cause cassava mosaic disease(CMD)and cassava brown streak disease(CBSD)pandemics.At the peak of CMD pandemic in the late 1990s,SSA2 was the prevalent whitefly,although its numbers have diminished over the last two decades with the resurgence of SSA1 whiteflies.Three SSA1 subgroups(SGI to SG3)are the predominant whiteflies in East Africa and vary in distribution and biological properties.Mating compatibility between SSA1 subgroups and SSA2 whiteflies was reported as the possible driver for the resurgence of SSA 1 whiteflies.In this study,a combination of both phylogenomic methods and reciprocal crossing experiments were applied to determine species status of SSA1 subgroups and SSA2 white-fly populations.Phylogenomic analyses conducted with 26548205 bp whole genome single nucleotide polymorphisms(SNPs)and the full mitogenomes clustered SSA1 subgroups together and separate from SSA2 species.Mating incompatibility between SSA1 subgroups and SSA2 further demonstrated their distinctiveness from each other.Phylogenomic analyses conducted with SNPs and mitogenomes also revealed different genetic relationships among SSA1 subgroups.The former clustered SSA 1-SGI and SSA1-SG2 to-gether but separate from SSA1-SG3,while the latter clustered SSA1-SG2 and SSA1-SG3 together but separate from SSA 1-SG1.Mating compatibility was observed between SSA 1-SGI and SSA1-SG2,while incompatibility occurred between SSA 1-SGI and SSA1-SG3,and SSA 1-SG2 and SSA 1-SG3.Mating results among SSA 1 subgroups were coherent with phylogenomics results based on SNPs but not the full mitogenomes.Furthermore,this study revealed that the secondary endosymbiont--did not mediate reproductive success in the crossing assays carried out.Overall,using genome wide SNPs together with reciprocal crossings assays,this study established accurate genetic relationships among cassava-colonizing populations,illustrating that SSA1 and SSA2 are distinct species while at least two species occur within SSA1 species.