Parthenocarpy is a desirable trait for cucumber production and is particularly valuable in environments where pollination is difficult or adversely affected by abiotic factors. Parthenocarpic cucumber cultivars have been successfully developed, but the genetic and molecular mechanisms behind parthenocarpic expression remain largely unknown. Since parthenocarpy is often considered a yield component, it is difficult to separate the true parthenocarpic character from other yield related traits. Therefore, this study was designed to better define what is considered true parthenocarpic expression and then to use this knowledge to identify QTL associated with parthenocarpic fruit set. Building off of previous studies demonstrating that parthenocarpic fruit set is initiated in the days before and immediately after anthesis, a new approach to phenotyping parthenocarpic fruit set in cucumber focused on early fruit initiation and development was implemented. With a clear approach to phenotypic evaluation, a mapping population consisting of 205 F3 families derived from a cross between processing cucumber inbred lines `2A' (parthenocarpic) and `Gy8' (non-parthenocarpic) was evaluated for parthenocarpic fruit set. Genotypic data collected for each F2 individual was utilized to construct a linkage map consisting of 192 marker loci in seven linkage groups and covering 571.7 cM. Multiple QTL mapping methodologies (interval mapping, composite interval mapping, and multiple interval mapping) were employed to detect and construct optimal models for the inheritance of parthenocarpic fruit set. Seven additive QTL associated with parthenocarpic fruit set were detected with four identified consistently in all analyses. The four consensus QTL were located on chromosome 5 at 32.3 - 54.7 cM, chromosome 6 at 0.0 - 9.7 cM, chromosome 6 at 80.0 - 83.0 cM, and chromosome 7 at 21.8 - 32.1 cM. Bioinformatic analysis of the genomic regions harboring the four consensus QTL was conducted and multiple candidate genes were identified. A model was proposed to explain the roles of potential candidate genes in parthenocarpic expression observed in cucumber. The QTL identified for parthenocarpic fruit set by this study are valuable to cucumber breeders interested in developing parthenocarpic cultivars and to researchers interested in the genetic and molecular mechanisms of parthenocarpic fruit set.

This book provides an overview of the current state of knowledge of the genetics and genomics of the agriculturally important Cucurbitaceae plant family, which includes crops such as watermelon, melon, cucumber, summer and winter squashes, pumpkins, and gourds. Recent years have resulted in tremendous increases in our knowledge of these species due to large scale genomic and transcriptomic studies and production of draft genomes for the four major species, Citrullus lanatus, Cucumis melo, Cucumis sativus, and Cucurbita spp. This text examines genetic resources and structural and functional genomics for each species group and across species groups. In addition, it explores genomic-informed understanding and commonalities in cucurbit biology with respect to vegetative growth, floral development and sex expression, fruit growth and development, and important fruit quality traits.

This edited book presents the latest research on cucumber, its genetic resources and diversity, tissue culture and genetic transformation, mapping of economic genes and QTLs, whole genome sequencing, comparative genomics, and breeding strategies. The mechanism of sex expression, interspecific hybridization, and cell biology are also described. The book discusses the genome draft of cucumber and the application of genome editing. This book is useful to the students, teachers and scientists in academia and relevant private companies interested in horticulture, genetics, breeding, and related areas.

view than its own proper males should fecundate each blossom." ANDREW KNIGHT Philosophical Transactions, 1799 Pollination mechanisms and reproduction have a decisive bearing upon rational procedures in plant breeding and crop production. This book intends to furnish' under one cover an integrated botanical, genetical and breeding-methodologi cal treatment of the reproductive biology of spermatophytes mainly angiosperms; it is based on an advanced topical course in plant breeding taught at the Hebrew University of Jerusa lem. We have tried to present a coverage which is concise, but as comprehensive as possible, of the pollination mechanism and modes of reproduction of higher plants, and to illustrate topics, whenever practicable, by examples from cultivated plants. Nevertheless, some relevant publications may have escaped our attention or may not be mentioned because of various limitations. The book is organized into three parts. The first part starts with an evaluation of the significance of the different pollination mechanisms for plant breeding and crop produc tion, describes modes of reproduction in higher plants and discusses ecology and dynamics of pollination. The second part is devoted to crops propagated by self pollination and describes specific breeding procedures for such crops. The third part details sexual reproduction in higher plants and handles three mechanisms involved in the prevention of self pollination and their utilization in plant breeding: sex expres sion, incompatibility, and male sterility.

This edited book presents the latest research on cucumber, its genetic resources and diversity, tissue culture and genetic transformation, mapping of economic genes and QTLs, whole genome sequencing, comparative genomics, and breeding strategies. The mechanism of sex expression, interspecific hybridization, and cell biology are also described. The book discusses the genome draft of cucumber and the application of genome editing. This book is useful to the students, teachers and scientists in academia and relevant private companies interested in horticulture, genetics, breeding, and related areas.