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The study was to screen forage oat ( Avena sativa) varieties (lines) suitable for planting and utilization in Chongqing. The experiment studied the production performance, nutritional quality and disease resistance of 19 oat varieties, and used the grey correlation method for comprehensive evaluation. The results showed that Qingmu No.3 had the highest hay yield (1.26 kg/m²), which was significantly higher than other varieties except Baiyan No. 3 and other nine varieties ( P<0.05). The nutrient composition analysis showed that the variation of crude protein content was the largest (27.23%), among which Qingyin 2 had the highest crude protein content (21.87%), and the average crude protein of 19 varieties was 13.52%. Disease resistance analysis showed that high resistance varieties (HR) were Taike and Dahan, and eight varieties with disease resistance grade or above, and no rust immune varieties were found. The oat varieties with better performance were screened out by the comprehensive evaluation of grey relational degree method: Kanyan No. 4, Baiyan No. 3, Qingmu No. 3. The study indicates that Kanyan 4, Baiyan 3 and Qingmu 3 are suitable for promotion and utilization in Chongqing area. [ABSTRACT FROM AUTHOR]

Previous studies suggested rapid evolution of conodonts across the Permian–Triassic boundary (PTB), and the end-Permian mass extinction pattern varies in different sections in South China. Here we document a high-resolution conodont succession from a carbonate facies of the Changhsingian Stage and across the PTB at the Daijiagou section, about 35 km north to Chongqing City, Southwest China. Two genera and twelve species are identified. Seven conodont zones are recognized from the uppermost part of the Lungtan Formation to the lowest Feixianguan Formation. They are the Clarkina liangshanensis , C. wangi , C. subcarinata , C. changxingensis , C. yini , C. meishanensis , and Hindeodus parvus zones in ascending order. Based on the high-resolution biostratigraphical framework at Daijiagou, the end-Permian mass extinction was rapid and it began in the base of the Clarkina meishanensis Zone. Associated with the extinction, a negative excursion of δ 13 C carb started in the middle part of Clarkina yini Zone with a progressive shift of 1.6‰ to the middle part of the Clarkina meishanensis , followed by a sharp shift of 3.51‰ from the Clarkina meishanensis Zone to the Hindeodus parvus Zone. Our study also suggests that the Triassic index species Hindeodus parvus co-occurred with Hindeodus changxingensis and Clarkina zhejiangensis and directly overlies the Clarkina meishanensis Zone at the Daijiagou section. All these data from the Daijiagou section and some previous studies of other sections in Sichuan, Guizhou provinces and Chongqing City suggest that the first occurrences of Hindeodus parvus are slightly earlier than the sharp negative excursion of δ 13 C carb and the FAD at the Meishan GSSP section. We consider that the slight difference of the end-Permian mass extinction, chemostratigraphy and conodont biostratigraphy at Daijiagou and its adjacent areas is most likely subject to different lithofacies, fossil preservation, and the constraint on the stratigraphic resolution rather than a different tempo of the end-Permian mass extinction in a global sense. The whole Changhsingian conodont succession at Daijiagou provides a high-resolution correlation with other equivalent sections in the Palaeotethys. The controversial results of biostratigraphy and chemostratigraphy between the sections investigated in this paper and the Meishan GSSP section also provide some important implications that accurate chronocorrelation requires the evaluation of multiple, varied stratigraphcal signals rather than relying solely on the FAD of the Triassic index species Hindeodus parvus for recognizing the Permian–Triassic boundary (PTB). Growth series of abundant specimens for each species are figured. The taxonomy of some Hindeodus species in the PTB interval is updated. [ABSTRACT FROM AUTHOR]