Interspecific aneuploidy inCucurbita

Abstract

SUMMARYInterspecific aneuploids were made in the genusCucurbitaby pollinating the autoallotroploid (diploidC. moschata– haploidC. palmata) with pollen from diploidC. moschata. Seventy-eight, or 0·36%, of the potential ovules showed some degree of continued development after pollination. The high frequency of continued ovule and embryo development indicated a preferential distribution or loss ofC. palmataunivalents during meiosis in the autoallotriploid and that megagametes aneuploid for more than oneC. palmatachromosome were capable of initiating continued ovule development after fertilization. Lethal effects of interspecific aneuploidy were expressed by complete embryo abortion to sterility of mature plants. Nine plants developed to maturity and seven were cytologically identified. Four were trisomic and two were monosomic for singleC. palmatachromosomes, i.e. they were 2n+ 1 and 2n+ 19 (n= 20) respectively. One plant was 2nand phenotypically identical to theC. moschataparent. One 2n+ 1 plant was fertile and the singleC. palmatachromosome was transferred in the succeeding generation.