Analysis of nuclear DNA content and chromosome number for screening genotypes and crosses in Annual Ryegrass (Lolium multiflorum Lam.)

Abstract

This study determined the nuclear DNA content and chromosome number for screening genotypes and crosses in L. multiflorum from Brazil. Analyses to estimate nuclear DNA content by flow cytometry were performed in young leaves of four parental genotypes and eight offspring resulting from their crosses. To the chromosome counting, the slides were prepared by flame drying technique and Giemsa staining. The genotypes were classified in the following categories: diploid, triploid, and tetraploid with 14, 21 and 28 chromosomes, respectively. The Average content of DNA in diploids ranged from 5.42pg to 5.85pg. A single triploid plant showed 8.30pg. In tetraploids, the average DNA content ranged from 10.21pg to 10.95pg. Thus, the combination of analyses by DNA quantification and chromosome counting prove to be efficient for screening and diagnosing ploidy level of parents and crosses in Lolium.