Predominant paternal transmission of the mitochondrial genome in cucumber

Segregation analyses of restriction fragment length polymorphisms (RFLPs) in cucumber revealed one paternally inherited PstI genomic clone, possibly from either the mitochondrial (mt) or chloroplast (cp) genome. Polymorphisms in the mtDNA were identified with clones apocytochrome B and atp9. No polymorphisms were detected in the cpDNA using restriction enzymes that recognize 6 and 4 bp sequences. Two pairs of reciprocal crosses were made between individual plants of the breeding line Gy14 and cultivar Wisconsin SMR18 with USDA plant introduction 432860. A nuclear RFLP was biparentally inherited and established the hybrid origin of all progenies. For 68 of 70 progenies (97%), the mt genome of cucumber showed paternal transmission. Two hybrid plants possessed both parental fragments for one of the two polymorphic probe enzyme combinations, likely due to mitochondrial heterogeneity in the pollen parent