apple and 24 pear varieties w ere used as m aterials for this study.The num ber of chloroplast in stom ata guard cell, density, length and w idth of stom ata w ere observed. The re- sults show ed thatthe cluster analysis indicated thatploidy w as highly correlated to the num ber of chloroplastin guard celland the length ofstom ata. Ifthese tw o factors w ere added in discrim inant form ula, the reliability ofploidy identification in apple by discrim inantfunction w as sim ilar to its reliability based ...