判別洋香瓜（Cucumis melo L.）及非洲有角胡瓜（C. metuliferus E. Meyex Schrad）之種間雜交結果

Determination of the Interspecific Nature of a Cross between Cucumis melo L. and C. metuliferus E. Meyex Schrad

本實驗目的為（1）以田間天然授粉及密閉網室中蜜蜂授粉方式取得C. melo及C. metuIiferus之雜交品種；（2）以同功酶酶譜（isozyme banding pattern）及花粉母細包染色體減數分裂行為（meiotic chromosome behavior）去鑑定其雜交品種。實驗中使用一種具有黃色子葉幼苗之突變種，C. meIo C 879 J2，為母本與C. metuIiferus天然雜交，由於此黃色子葉之特性由隱性基因所控制，故其與任何具有綠色子葉之植物雜交則產生綠色子葉。此試驗之田間天然雜交中獲得7株具有綠色子葉之幼苗，但於網室栽培中並無綠色子葉產生。同時由同功酶酶譜及花粉母細胞染色體減數分裂行為中，鑑定此7株具有綠色子葉之F1，並非為C. melo C879 J2與C. metuIiferus之雜交，而可能為C. melo C879 J2與其它C. melo sp.之雜交，證明外來之因素過多，使得田間隔離不夠充分所致。

The purpose of this research were (1) to produce progeny from an interspecific cross between Cucumis melo and C. metuIife1US in an isolated field with natural bee pollination and in a screen cage with domesticated bees; (2) to identify the progeny with regard to isozyme banding pattern and meiotic chromosome behavior. A yellow cotyledon marker of C. melo, C 879 J2, was used to identify F1 progeny in naturally crossing populations. This mutant is known to be controlled by a single recessive gene; any cross with a plant having green cotyledons will result in offspring with green cotyledons. Based on this knowledge, C 879 J2 was planted in isolation with C. metuIiferus. Seven seedlings from an isolated field exhibited green cotyledons. None of the seedlings from cage exhibited this characteristic. Studies of their isozyme and meiotic chromosome behavior indicated that these progenies were not the result of an interspecific cross. The seven seedlings with green .cotyledons are the result of C. melo × C. melo crosses. It is proved that the isolated field is not totally isolated.