Broadness of leaf petiole wing (WE) was investigated as a morphologica
l marker for screening hybrids of the very narrow-winged species Citru
s limonia and C. sunki with broad-winged species C. aurantium and C. s
inensis. Controlled polinizations produced over 500 reciprocal hybrids
with potential in the ongoing rootstock breeding program identified b
y the Pgi-1 and Prx(a)-1 isozyme loci. Measurement ratios WB/leaf leng
th, WB/leaf broadness and WB/petiole length identified 86 to 91% of th
e reciprocal hybrids produced. However, visual classification of WE wa
s an equally efficient but much easier and faster method. It can be ve
ry useful in breeding programs when large number of plants have to be
screened or when isozyme, RFLP or RAPD laboratories are not available.