The influence of parents, mating systems, and planting date on the transfer of gynoecious flowering to Chinese cucumbers (Cucumis sativus L.)

Graduation date: 1989Gynoecious inbred lines of cucumbers (Cucumis sativus\ud L.) with high (HF), medium (MF) and low (LF) percentage of\ud gynoecious plants were used in crosses with monoecious\ud Chinese cultivars with high (HN), medium (MN) and low (LN)\ud percentage of nodes with female flowers. F₁ and F₂ progenies\ud from these parents crossed in all combinations were studied\ud to determine the effect of levels of female flowering\ud expression of gynoecious and monoecious parents on the\ud percent gynoecious plants. The effect of mating systems on\ud percent gynoecious plants and percent gynoecious plants with\ud Chinese cucumber characters, wart-spine and long fruit, was\ud studied in F₃ families from crosses of HF, MF, and LF\ud gynoecious lines with an HN monoecious parent. The effect of\ud planting date on percent gynoecious plants recovered was\ud studied in the F₂ progenies of an HF gynoecious line crossed\ud with Taishan, an MN monoecious cultivar. Level of female\ud flowering tendency, expressed by percentage of female\ud flowering nodes, in the monoecious parents had a much\ud greater effect on the percentage of gynoecious plants in the\ud F₁ and F₂ generation than did the degree of female flowering\ud in the gynoecious parents. The effect of the gynoecious\ud parent and the interaction of gynoecious X monoecious parent\ud on percent gynoecious plants in the F₁ were non significant.\ud In the mating system study, self pollination of selected\ud completely gynoecious plants, requiring male flowering\ud induction by chemical treatment, was significantly more\ud effective in obtaining highly gynoecious progeny lines than\ud selfing predominately gynoecious plants or sib-mating\ud predominately gynoecious and completely gynoecious plants.\ud There was no interaction between mating system and level of\ud female flowering in the gynoecious parents.\ud Planting date did not affect the percent of plants\ud producing male flowers during the entire growing period, but\ud early planting produced fewer plants with male flowers\ud during the first half of their respective growing period\ud than late plantings. By the end of the season, early and\ud late planting were about equal in percentage of gynoecious\ud plants, because a higher percentage of plants in the early\ud plantings reverted from gynoecious to monoecious flowering\ud during the last half of the growth period