By field inocula tion to simulate the natural occurrence of f rogeye leaf- spo t o f soybean in o rder to get plo ts wi th dif ferent di sease sev eri ty theinfluence o f each class of diseasesev eri ty on yield, abo rtiv e pod ra te and w eight o f 100 seeds w ere assessed. The result show that sev erity of class 2 induced o bvio us yield lo ss. Three o ptimized models fo rthe influence of different class of sev eri ty in v arious grow th stages w ere establi shed bybina ry po lynomial stepw ise reg ression analy sis w ith g row th stage and sev eri ty class asindependant va riables and yield, abo rtive pod rate and w eight of 100 seeds as dependentra riables. The models of po pulatio n yield loss due to infectio n o f soybean f rog ey e leafspo t w ere a lso establi shed by the same w ay. By analy sis o f co rrelatio n it was show n thatthe seed beginning stage w as the cri tical g row th stag e for yield loss assessment , the diseasesev eri ty o f tha t stage caused the g rea test yield loss. Two models fo r cri tical pointw ere dev elo ped.
References:
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