The inheritance of cold tolerance in seven interspecific grape populations

The interspecific cross is an important breeding strategy in grape breeding program. Vitis amurensis is a wild species native to China that can withstand extreme cold temperatures. In this study, we used seven populations of different combinations, and six of these populations are of Vitis amurensis pedigree. The low temperature exotherms (LTEs) were used to evaluate the cold tolerance of grapes, and the results indicated that the cold tolerance inheritance of V. amurensis is very strong and additive and the broad-sense heritability ranged from 0.54 to 0.71 in seven populations. The LTE values distributed in the progeny in a normal, continuous manner despite a wide range of variation, indicating that their presence and concentration is a quantitative trait, controlled by polygenes. In addition, evidence of transgressive inheritance was noted, indicated by the exceptionally high cold tolerance observed amongst some of the progenies. These results are of both practical and scientific interests for further breeding efforts and researches on different cold tolerance in grape

Proteomic variation in Vitis amurensis and V. vinifera buds during cold acclimation

Amur grape (Vitis amurensis) is a wild grape species with excellent freezing tolerance compared with the widely cultivated common grapevine (V. vinifera). Here, we investigated the effect of cold acclimation (CA) on the proteomes of V. amurensis (cv. Zuoshan-1) and V. vinifera (cv. Jingzaojing) buds to explore the cold-tolerance mechanisms used by these species. The buds were collected in late fall (October) and early winter (December) and subjected to an iTRAQ-based proteomic analysis. A total of 472 and 713 differentially abundant proteins (DAPs) were identified between the two time points in V. amurensis and V. vinifera, respectively. The two species shared 235 DAPs, which were mainly involved in the protein chaperone and metabolic pathways, particularly carbohydrate metabolism. These DAPs represent the general responses to CA in Vitis species. V. amurensis contained less unique DAPs (237) than V. vinifera (478). A functional category analysis indicated that the phenylpropanoid biosynthesis pathway was enriched in V. amurensis. Among the DAPs identified in this pathway, seven upregulated and three downregulated DAPs were present in V. amurensis, while three upregulated and 20 downregulated DAPs were present in V. vinifera. Contrasting patterns were observed between the two species for phenylalanine ammonia-lyase, cinnamoyl-CoA reductase 1, and shikimate O-hydroxycinnamoyl transferase, which accumulated in V. amurensis but decreased in V. vinifera. The qRT-PCR results indicated that the transcriptional changes of 12 genes encoding selected DAPs were all consistent with the changes observed at the protein level. Our work provides new insights into the mechanisms by which cold hardiness is achieved in V. amurensis buds

A study on the thermal conductivity of proton irradiated CVD-SiC and sintered SiC, measured using a modified laser flash method with multi-step machining

CVD-SiC and sintered SiC (SPS-SiC) were proton irradiated at 340 ̊C receiving different levels of damage (0.05–0.25 dpa). A novel multi-step machining and measurement method using laser flash analysis (LFA) was developed to derive the thermal conductivity of the irradiated layer (∼46 µm). Before irradiation, the thermal conductivity of SPS-SiC was much lower than CVD-SiC, primarily due to its higher intrinsic defect concentration and smaller grain size which provide a greater density of barriers to phonon transmission. Following irradiation, major thermal conductivity degradation (∼90%) was found to occur to both types of SiC after only a low dose (∼0.1 dpa), with both saturating at a similarly low value (a few W/K⋅m), as the thermal resistivity due to the presence of high density of grain boundaries became less important. Thermal conductivity degradation after irradiation was primarily caused by point defects in both types of SiC, as reflected by Raman spectra

A study on the thermal conductivity of proton irradiated CVD-SiC and sintered SiC, measured using a modified laser flash method with multi-step machining

CVD-SiC and sintered SiC (SPS-SiC) were proton irradiated at 340 ̊C receiving different levels of damage (0.05–0.25 dpa). A novel multi-step machining and measurement method using laser flash analysis (LFA) was developed to derive the thermal conductivity of the irradiated layer (∼46 µm). Before irradiation, the thermal conductivity of SPS-SiC was much lower than CVD-SiC, primarily due to its higher intrinsic defect concentration and smaller grain size which provide a greater density of barriers to phonon transmission. Following irradiation, major thermal conductivity degradation (∼90%) was found to occur to both types of SiC after only a low dose (∼0.1 dpa), with both saturating at a similarly low value (a few W/K⋅m), as the thermal resistivity due to the presence of high density of grain boundaries became less important. Thermal conductivity degradation after irradiation was primarily caused by point defects in both types of SiC, as reflected by Raman spectra