Abstract:

To study the chromosome ploidy of ‘Abelmoschus manihot No.3’, using the new root tip of ‘Abelmoschus manihot No.3’ as material, the chromosome ploidy analysis was carried out by conventional squash method. The results showed that ‘Abelmoschus manihot No.3’ was diploid with 66 chromosomes, and the karyotype formula was K (2n)=2x=66. The hybrid F₁ could be obtained by crossing ‘Abelmoschus manihot No.3’ and allotetraploid upland cotton ‘Han 818’ with 52 chromosomes. The results showed that the hybrid F₁ could be obtained from the cross combination with ‘Abelmoschus manihot No.3’ as female parent. The PCR amplification results showed that the hybrid contained parental specific bands. The hybrid could develop normally, but the pollen was abortive and could not bear. All the young bolls of the hybrid combinations with ‘Abelmoschus manihot No.3’ as male parent fell off, and no hybrid was obtained. The results of squash showed that there were 59 chromosomes in the new root tip of F₁ hybrid, which further confirmed that F₁ hybrid was obtained by crossing parents. This study revealed for the first time the genetic regularity of chromosome ploidy and intergeneric hybridization in this species, which could provide a theoretical basis for further study on cytogenetics of Abelmoschus manihot .

Key words: Abelmoschus manihot, ploidy analysis, cotton, distant hybridization, intergeneric hybridization