Cytogenetics of Zea diploperennis, Zea mays and their F1 hybrid

Date

3-1992

Degree

Bachelor of Science in Biology

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Dolores A. Ramirez

Abstract

Zea diploperennis, Zea mays and Zea diploperennis x Zea hybrids were cytologically evaluated. Cytological examination revealed a chromosome number of 2n=20 for the teosinte, corn and their hybrid. Meiotic irregularities like laggards, bridges, early and late disjunctions, bridge and fragment were observed at significant frequencies in Meiosis I but at low frequencies in Meiosis II. Pollen fertility, however, was quite high for the three populations (97.80%, 98.13%, 88.44% for L. diploperennis, mars and F1, respectively). This indicated that the irregularities observed in Meiosis did not have a significant effect in the proper segregation of the chromosomes leading to fertile gametes. Pachytene analysis showed that the chromosomes of the parents have similar morphology. Lengths and arm ratios of the chromosome pairs are close to each other. The parents and the hybrid are characterized by having submetacentric and metacentric chromosomes. Observations on the chromosome pairing in the hybrid at pachytene indicated that the chromosomes of both species are homologous. Loose pairings were observed (segmental and terminal) which shows that there are segments in the chromosomes of both species that are different. Results indicate that the two species are closely related and are thus cross-compatible.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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