Characteristics of genetic resources in bottle gourd

Tochigi Prefecture started breeding bottle gourd (Lagenaria siceraria var. hispida) in 1928. To breed pest-resistant varieties, the prefecture has also collected bottle gourd and gourd(Lagenaria siceraria var. gourda) varieties mainly from Southeast Asia since 1959. The prefecture now holds 107 such genetic resources, whose data the auhors have compiled and collated for such characteristics as natural fructification and resistance to Green Mottle Mosaic Virus (GMMV) and Watermelon Mosaic Virus (WMV). The authors conjecture that varieties with wavy leaf shapes are resistant to GMMV but found no common morphological characteristic in varieties resistant to WMV. Replacement resulted in morphological changes in some years. The authors infer that lack of true breeding at introduction and human errors at artificial crossing and fruit collection were likely causes of the morphological changes.