抄録
In the improvement of crop p. Iants by hybridization., it is desrrable that he parental varieties sh, ould differ from each other with regard to as many pairs of genes as possible when q, u:antitative characters are concerned. The genetic make-up of varieties closely related are likely to be very similar and that of remotely related ones likely to be dissimilar- Any survey or potential parental material should, therefore, take into account the relationship among the strains under consideraticn. Thus, in the case of autogamous plants, it is desirable for the breeder to know how varieties grown in his breeding nursery are related to each other .
