Variation Analysis of Seed and Seedling Traits of Cross Combination Progenies in Populus

Twenty-five species and hybrids in Populus were used as parents, and 26 cross combinations, including more than 5000 seedlings, were obtained by artificial cross breeding. The length of infructescence, number of seeds per infructescence, thousand-seed weight, germination rate of seeds among these cross combinations were tested. The results indicated that the cross combinational effects were significant for these traits, and demonstrated that the length of infructescence, thousand-seed weight were positively affected by female parent. In addition, seedling height, diameter above ground, diameter at breast height （DBH） of 17 cross combination progenies were investigated. The analysis of mean and standard deviation of these three traits showed that seedling height, diameter above ground, DBH had extensive variation among combinations and individuals within combination. Variance analysis and estimate of heritability indicated that the three traits had wide variation and were controlled by heredity. It was feasible to select superior cross combinations and seedlings. Further more, the result of multiple comparison showed that P.deltoides ‘Lux＇× P.deltoides ‘D324＇, P.ussuriensis cl. ‘U4＇× P deltoides ‘T66＇, P.ussuriensis cl. ‘U4＇× P. deltoides ‘T26＇, P.deltoides ‘Lux＇× P.ussuriensis cl. ‘U3＇, （P.tomentosa×P.bolleana）×（P.alba×P.glandulosa）, （P.alba×P.tomentosa）×（P.alba×P.glandulosa）, and （P.alba×P.glandulosa‘No.2＇）× P. tomentosa ‘Lumao 50＇ were superior cross combinations with higher growth rate. Finally, 123 elite seedlings were selected for further test.

Growth Performance of Different Cross Combinations of Quality Lean Type Pig

Ten healthy weaning piglets of Landrace x Yorkshire （LY） in good body condition with body weight of （24 ± 1.27） kg were selected, and ten weaning piglets of Berkshire × LY （BLY） and Duroc × LY （DLY） with similar situation were also selected respectively to study the growth performance of different cross combinations. Three groups of experimental pigs were bred with conventional diet. The results showed that the average dry matter intakes of combinations of BLY and DLY were slightly decreased by 4.97% and 5.47% compared with the combination of LY, while average daily gain was significantly increased by 3.13% and 1.14%, and feed-weight ratio was decreased by 7.94% and 6.35%, respectively; economic benefit per pig was increased by 0.61 and 0.41 yuan, respectively. The combinations of BLY and DLY have better growth performance, which can be promoted in the production.

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.

Simple, Rapid and Sensitive Detection of Pseudomonas aeruginesa by Colorimetric Multiple Cross Displacement Amplification

Pseudomonas aeruginosa(P:aeruginosa)is a major opportunistic pathogen in hospital-acquired infections.Thus,carly diagnosis is the best strategy for fighting against these infections.In this report,we incorporated multiple crOsS displacement amplification(MCDA)combined with the malachite green(MG)for rapid,sensitive,specific and visual detection of P.aeruginosa by targeting the oprl gene.The MCDA-MG assay was conducted at 67°C for only 40 min during the amplification stage,and then products were directly detected by using colorimetric indicators(MG),eliminating the use of an electrophoresis instrument or amplicon analysis equipment.The entire process,including specimen processing(35 min),amplification(40 min)and detection(5 min),can be finished within 80 min.All 30 non-P.aeruginosa strains tested negative,indicating the high specificity of the MCDA primers.The analytical sensitivity of the MCDA-MG assay was 100 fg of genomic templates per reaction in pure culture,which was in complete accordance with MCDA by gel clectrophoresis and real-time turbidity.The assay was also successfully applied to detecting P.aeruginosa in stool samples.Therefore,the rapidity,simplicity,and nearly equipment free platform of the MCDA-MG technique make it possible for clinical diagnosis,and more.