During the autumn/spring “off” season, yield and quality of tomatoes are often affected by insufficient CO ₂ and low light in greenhouse production. Although tomato is one of the most widely cultivated vegetables, few studies have investigated the interactive effects of supplementary light and CO ₂ enrichment on its growth, photosynthesis, yield, and fruit quality in greenhouse production. This study investigates the effects of supplementary light (200 ± 20 μmol·m ^–2 ·s ^–1 ) and CO ₂ enrichment (increases to about 800 μmol·mol ^–1 ), independently and in combination, on these parameters in autumn through spring tomato production. Compared with tomatoes grown under ambient CO ₂ concentrations and no supplementary light (CaLn), supplementary light (CaLs) and supplementary light and CO ₂ enrichment (CeLs) significantly promoted growth and dry weight accumulation. Meanwhile, CO ₂ enrichment (CeLn) and CaLs significantly improved photosynthetic pigment contents and net photosynthetic (Pn) rates, whereas CeLs further improved these and also increased water use efficiency (WUE). CeLn, CaLs, and CeLs significantly increased single fruit weight by 16.2%, 28.9%, and 36.6%, and yield per plant by 19.0%, 35.6%, and 60.8%, respectively. The effect of supplementary light on these parameters was superior to that of CO ₂ enrichment. In addition, CaLs and CeLs improved nutritional quality significantly. Taken together, CeLs promoted the greatest yield, WUE, and fruit quality, suggesting it may be a worthwhile practice for off-season tomato cultivation.

Zhenba bacon (ZB), a type of Chinese traditional bacon with a long history, has attracted considerable attention in the Southwest of China for its unique flavor. To elucidate the changing course of aroma components during the process of ZB, four stages of process stages were assessed by GC–MS and GC–IMS coupled with multivariate data analysis. A total of 44 volatile compounds were identified by GC–IMS, including 5 esters, 8 alcohols, 12 aldehydes, 3 ketones, 1 furan and 2 sulfides; 40 volatile compounds were identified by GC–MS, 4 ketones, 7 phenols, 8 alcohols, 6 esters, 6 aldehydes, and 6 other compounds were detected. During the curing period, the amount and content of esters in Zhenba bacon gradually increased. Phenols appear in large quantities during the smoking period. The VOCs (volatile organic compounds) in the gallery plots were the most diverse in YZ samples, which are mainly esters. POV (peroxide value) and TBARS (thiobarbituric acid reactive substance) showed that lipid oxidation played an important role in the formation of volatile flavor components of bacon. This study provides valuable analytical data to explain the flavor formation of Zhenba bacon.

Association mapping has been widely used to map the significant associated loci responsible for natural variation in complex traits and are valuable for crop improvement. Sugars and organic acids are the most important metabolites in tomato fruits. We used a collection of 174 tomato accessions composed of S. lycopersicum (123 accessions) and S. lycopersicum var cerasiforme (51 accessions) to detect significantly associated loci controlling the variation of main sugars and organic acids. The accessions were genotyped with 182 SSRs spreading over the tomato genome. Association mapping was conducted on the main sugars and organic acids detected by gas chromatography-mass spectrometer (GC-MS) over two years using the mixed linear model (MLM). We detected a total of 58 significantly associated loci (P<0.001) for the 17 sugars and organic acids, including fructose, glucose, sucrose, citric acid, malic acid. These results not only co-localized with several reported QTLs, including fru9.1/PV, suc9.1/PV, ca2.1/HS, ca3.1/PV, ca4.1/PV and ca8.1/PV, but also provided a list of candidate significantly associated loci to be functionally validated. These significantly associated loci could be used for deciphering the genetic architecture of tomato fruit sugars and organic acids and for tomato quality breeding.