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Summary One durum wheat line (Triticum durum), cv. 82PCD476, with useful BYDV tolerance or resistance, was singled out of 5 152 lines evaluated between 1979 and 1986. A few other lines such as cv. Boohai and cv. 12th IDSN 227, slightly inferior to cv. 82PCD476, also showed some value. With an hybrid of cv. 12th IDSN227 with the susceptible cv. 84PCY-S531, broad-sense heritability values of 0.37–0.41 were obtained for symptoms and a heritability value of 0.55 was obtained for the total weight of spikes. The weight of spikes was considered as a good indicator of wheat tolerance to BYDV. Although BYDV resistance or tolerance genes are not very common in durum wheat, sources of heritable resistance could be found. However, the resistance ofT. aestivum to BYDV was superior to the one found inT. durum.Cintribution no. 323  相似文献   
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节水灌溉方式下作物需水量和灌溉需水量研究综述   总被引:8,自引:3,他引:5  
中国是一个严重缺水的国家,农业用水浪费严重,发展节水农业势在必行。作物生长需水量与灌溉需水量密切相关,作物生长需水量估算方法各异,并以彭曼公式为主,该公式与参照作物需水量(ET0)和作物生长系数(Kc)有关。计划灌溉需水量是节水灌溉管理的一个重要因素,其定额方式各有利弊,仍然以农田水量平衡方程为主要评估手段。  相似文献   
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In addition to six cyclopeptide alkaloids lotusines A-F, a new compound lotusine G, was isolated from the root bark of Zizyphus lotus by centrifugal partition chromatography.  相似文献   
4.
An in vitro gas production(GP) technique was used to investigate the effects of combining different doses of Salix babylonica extract(SB) with exogenous fibrolytic enzymes(EZ) based on xylanase(X) and cellulase(C), or their mixture(XC; 1:1 v/v) on in vitro fermentation characteristics of a total mixed ration of corn silage and concentrate mixture(50:50, w/w) as substrate. Four levels of SB(0, 0.6, 1.2 and 1.8 m L g–1 dry matter(DM)) and four supplemental styles of EZ(1 μL g–1 DM; control(no enzymes), X, C and XC(1:1, v/v) were used in a 4×4 factorial arrangement. In vitro GP(m L g–1 DM) were recorded at 2, 4, 6, 8, 10, 12, 24, 36, 48 and 72 h of incubation. After 72 h, the incubation process was stopped and supernatant p H was determined, and then filtered to determine dry matter degradability(DMD). Fermentation parameters, such as the 24 h gas yield(GY24), in vitro organic matter digestibility(OMD), metabolizable energy(ME), short chain fatty acid concentrations(SCFA), and microbial crude protein production(MCP) were also estimated. Results indicated that there was a SB?EZ interaction(P0.0001) for the asymptotic gas production(b), the rate of gas production(c), GP from 6 to 72 h, GP2(P=0.0095), and GP4(P=0.02). The SB and different combination of enzymes supplementation influenced(P0.001) in vitro GP parameters after 12 h of incubation; the highest doses of SB(i.e., 1.8 m L g–1 DM), in the absence of any EZ, quadratically increased(P0.05) the initial delay before GP begins(L) and GP at different incubation times, with lowering b(quadratic effect, P0.0001) and c(quadratic effect, P0.0001; linear effect, P=0.0018). The GP was the lowest(P0.05) when the highest SB level was combined with cellulose. There were SB?EZ interactions(P0.001) for OMD, ME, the partitioning factor at 72 h of incubation(PF72), GY24, SCFA, MCP(P=0.0143), and p H(P=0.0008). The OMD, ME, GY24 and SCFA with supp lementation of SB extract at 1.8 m L g–1 DM were higher(P0.001) than the other treatments, however,PF72 was lower(quadratic effect, P=0.0194) than the other levels. Both C and X had no effect(P0.05) on OMD, p H, ME, GY24, SCFA and MP. The combination of SB with EZ increased(P0.001) OMD, ME, SCFA, PF72 and GP24, whereas there was no impact on p H. It could be concluded that addition of SB extract, C, and X effectively improved the in vitro rumen fermentation, and the combination of enzyme with SB extract at the level of 1.2 m L g–1 was more effective than the other treatments.  相似文献   
5.
中国是一个严重缺水的国家,农业用水浪费严重,发展节水农业势在必行。作物生长需水量与灌溉需水量密切相关,作物生长需水量估算方法各异,并以彭曼公式为主,该公式与参照作物需水量(ET0)和作物生长系数(Kc)有关。计划灌溉需水量是节水灌溉管理的一个重要因素,其定额方式各有利弊,仍然以农田水量平衡方程为主要评估手段。  相似文献   
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