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

• Published in: Australian Journal of Crop Science Vol. 9; no. 7; pp. 666 - 670
• Main Authors: de Oliveira Bustamante, Fernanda, Rocha, Laiane Corsini, de Souza Santos, Natalia, Silveira, Raphaela Aparecida Duarte, Nunes, Renata de Castro, Mittelmann, Andrea, Techio, Vania Helena
• Format: Journal Article
• Language: English
• Published: Lismore, N.S.W Southern Cross Publishers 01.07.2015
• Subjects: Analysis; DNA; Flow cytometry; Italian ryegrass; Lolium multiflorum; Methodology; Plant breeding; Plant chromosome numbers; Polyploidy
• ISSN: 1835-2693

'Lolium multiflorum' Lam. (annual ryegrass) is a forage grows in temperate regions of the world. In South America, annual forms of 'L. multiflorum' exist and have been used as forage for a long time in Argentina, Chile, Uruguay, and Brazil. 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'. This information may be used reliably for prior selection of genotypes for the breeding program.