how to get smooth edge of this image, and how to solve the problem of over segmentation

Hi friends,

    i want to separate touching kernels.i have used watershed segmentation for this purpose. But watershed results in over segmentation.Also, border is not smooth.Can anyone help me to solve this problem

 % grains = rgb2gray(img);
grainsBW = im2bw(grains,110/255);
G=grainsBW;
revim = imcomplement(grainsBW);
figure,imshow(revim,[])
D = bwdist(revim);
D2 = imcomplement(D);<<http://imageshack.us/photo/my-images/209/jcki.jpg/>>
figure,imshow(D2,[])
% Suppress shallow minima
D3 = imhmin(D2,1);
L = watershed(D3);
grainsBW(L == 0) = 0;
figure,imshow(grainsBW);

mark = imerode(G,se); mark1=im2bw(mark); %%%%%%%%%%% marker se = strel('disk',70); %%%% 30 figure, imshow(mark1); x= grainsBW|mark1; %%%%%%%%%% marker and watershed output figure,imshow(x);%%%%%%%%%%%%%%%%%%%% can stop here n do some alteration &&&& THIS IS SAME AS RESULT 1.f title('watershed output or with marker');

e=edge(x,'sobel'); figure,imshow(e); I4 = bwmorph(e,'spur'); figure,imshow(I4);