小麦条锈病对小麦产量影响的研究——Ⅱ.病害对小麦叶片光合作用的影响初探

利用红外线气体分析仪测定了冬小麦燕大1817和东方红3号在受到条锈菌(Puccinia striiformis West)侵染后叶片光合作用的变化。证明严重度S越高,残余健部光合作用极大值P′_(max)越低,其关系为P′_(max)=P′_(max)(1-0.826*S)。根据试验数据推导建立了条锈病导致的光合产物降低率预测模型:L_(光合)=1-(P_(max)+I_(1α))/(P′_(max)+I_(1α))(1-bS)(1-S),和理论模型L_(光合)=aS~n,n=f(P′_(max)/P_(max))。最后讨论了L_(光合)与验经产量损失模型的关系。     

小麦条锈病对小麦产量影响的研究——Ⅲ.病害对寄主库-源关系的影响

利用剪叶和测定扬花期后植株各器官干重变化等方法研究了小麦条锈病对小麦库-源关系的影响。研究结果表明:染病植株各叶片的绝对贡献值减小;相对贡献值不变,各叶片间功能比例关系不交,植株内的相互补偿作用降低。同时还发现染病植株可通过减少库容,缩短生育期,增大相对输出率等反馈机理来调节库-源关系,并且病情越重,相对输出率越大,经济系数越低。     

小麦条锈病对小麦产量影响的研究——Ⅰ.损失估计经验模型

1983—1984年和1984—1985年两生长季中同时在北京和郑州设点,就小麦条锈病(Puccinia striiformis tritici West.)对冬小麦燕大1817产量的影响进行了研究。在这两个不同的流行地区中,通过小区整体分期接种和间隔梯度喷药等方法,获得了流行表现种种不同的小区103个。利用这些数据分别建立了CP,MP,AUDPC三种模型,比较结果表明,CP模型最佳。本文还提出了一种AUDPC值标准化的方法。     

COMPONENT ANALYSIS OF SLOW-RUSTING RESISTANCE OF WHEAT CULTIVARS TO STRIPE RUST (Puccinia striiformis) (Ⅰ)

Under field conditions in 1984 and 1985, resistance components (infection frequency, sporulationcapacity, latent period, lesion size expansion and infectious period) were quantified on six wheat cultivarsinoculated with 3 races of Puccinia striiformis at three different growth stages. The five resistance com-ponents of slow-rusting cultivars were significantly different from those of the check cultivar, and thevariance among cultivars occupied the most part of total variance. The cultivar×race interactions eitherwere insignificant or only occupied a very small proportion of the total variance. Results of estimation ofthe resistance component parameters were fitted to the apparent infection rates of these cultivars in thefields.     

小麦条锈病(Puccinia striiformis)慢锈品种流行模拟模型

本文根据抗病性组份的田间实测值,组装了小麦条锈病慢锈性模拟模型——SRESM1。经初步检验认为:模拟出的流行趋势同实际情况大体相符;模型在生物学和逻辑上是合理的;各抗性组份中,侵染机率、产孢量和病斑扩展速度在慢锈流行中起主要作用,潜育期的作用其次,传染期的作用最小。通过变换初始菌量和气象条件,有助于分析慢锈品种的抗性潜力,估计其应用价值。     

小麦条锈病(Puccinia striiformis)慢锈品种抗性组份的研究Ⅰ

1984,1985两年在田间测定了6个小麦品种与3个条锈菌小种组合在不同生育时期下的抗病性组份:侵染机率、产孢量、潜育期、病斑扩展速度和传染期。5个慢锈品种分别同对照相比,在5个组份上的差异均极显著,品种间差异方差占总方差的绝大部分。各组份中,品种×小种互作或不显著,或虽显著但在总方差中所占比例很小。各品种组份参值测定结果和各品种田间流行表观速率是相符的。     

AN EPIDEMIC SIMULATION MODEL OF STRIPE RUST (Puccinia striiformis) ON SLOW RUSTING CULTIVARS OF WHEAT (Ⅱ)

The Slow Rusting Epidemic Simulation Model (SRESMI) was built based on the resistance com-ponent data obtained from field experiments. In the preliminary validation of the model, the simulatedepidemics basically conformed to the observed ones and the structure of the model seemed to be basicallycorrect. Among the resistance components, infection frequency, sporulation capacity and the lesion expan-sion rate played the most important role in the slow rusting epidemic, while the latent and infectiousperiods did the less and the least, respectively. This model may be useful for the exploration of slow-rusting breeding and the evaluation of the potential effectiveness of slow-rusters in practical cultivationunder different epidemic pressures.     

STUDIES OF CROP LOSS CAUSED BY STRIPE RUST ON WINTER WHEAT (Ⅲ)——DISEASE EFFECT ON THE SINK-SOURCE RELATIONSHIP OF HOST

Two methods, leaf-detaching and interval weighing of dry matter of different organs, were used to study the effect of stripe rust (Puccinia striiformis tritici West.) on the sink-source relationship of winter wheat Yianda 1817. The results showed that on diseased plants the absolute contribution value of each leaf arrangement was reduced; the relative contribution value of each leaf arrangement was unchanged; the contribution weights among the leaf arrangements were constant; the compensation among the leaf arrangements decreased. The results also showed that the diseased host could regulate its sink-source relationship by feedback mechanism, such as reducing the size of sink, shortening the perilod of growth, and increasing the relative translocation rate. The more serious the disease scverity, the greater the relative translocation rate and the smaller the economical index.     

STUDIES ON CROP LOSS CAUSED BY STRIPE RUST ON WINTER WHEAT (Ⅱ)——EFFECT OF DISEASE ON THE LEAF PHOTOSYNTHESIS

Winter wheat was used to investigate the effect of stripe rust (Puccinia striiformisWest.) on the photosynthesis of leaves with different disease severity. The rates of CO_2 uptakeof leaves were measured with an infrared gas analyzer. The results showed that on the dis-eased leaves the maximum rate of photosynthesis of the uncolonized part (P'_(max)) was negative-ly proportional to the disease severity and could be described as P'_(max)=P_(max)*(1- 0. 826*S).The photosynthsis model was built as P = I*@*P_(max)* (1 - b*S)/(P_(max)* (1- b*S) + I*@).From this model two relative photosynthesis reduction models were deduced: L_(photo) = A*S~n,where n = f(P'_(max)/P_(max)), and L_(photo) = 1 - (1 - S)*(1-b*S)*(P_(max) + I*@)/(P'_(max) + I*@).The relationship between the critical point crop loss model and these models was discussed.     

小麦条锈病三种显症率预测式的比较

本文证明小麦条锈病显症率的变化主要决定于有效积温。通过田间人工接种试验,观察了累积显症率与累积有效积温的关系,获得数据的相应点图大体呈“S”型曲线分布。选择并建立了Weibull函数、逻辑斯谛模型和函数Y=sin~2(aX b)(a,b为常数)等三种形式的数学模型,以描述这些点的分布,并比较它们各自的拟合度。认为下面的逻辑斯谛模型最好。其中,PP_i为第i天累积显症率,TT_i为侵入日到调查日(第i天)的累积有效积温。