Somaclonal variants from an intergeneric hybrid: Saccharum spp. hybrid x Erianthus arundinaceum

Abstract

Somaclonal variation from a partially sterile intergeneric hybrid was obtained for sugarcane improvement and for understanding phylogeny. Over 1,000 somaclones were regenerated from callus cultures of intergeneric hybrid clone H83-9998 (2n = ca. 94) involving H62-4671 (Saccharum spp. hybrid, 2n = ca. 115) x 28NG7 (Erianthus arundinaceum, 2n = 60) as parents. One hundred twenty-six somaclones were selected on the basis of observed morphological variation and planted in large plots with the original hybrid and its parental clones for detailed studies. Data were collected for stalk (number, length, diameter), leaf (length, width) and sucrose characters. Obvious variations in dewlap shape, leaf and stalk colors, leaf angle, rhizome habit, and pollen fertility, as well as date of flowering, were recorded. Chromosome and isozyme analyses were conducted to confirm that the observed phenotypic variation among somaclones had a genetic basis. Chromosome numbers of somaclones selected on the basis of phenotypic variation ranged from 2n = 66 to 2n = 109. With isozyme analysis, 1 to 4 band variations in three systems (peroxidase, phosphoglucomutase, and phosphoglucoisomerase) were found. Significant genetic variance estimates (σG2/σP2) and genetic CVs (6.7–25.6%) indicate that the differences observed among somaclonal variants would likely remain stable in additional asexually propagated cycles. Yield was estimated from stalk volume x refractometer solids, and 9 out of 126 somaclones produced higher estimates yield than the hybrid. One somaclone showed estimated yield that was not significantly different from the Saccharum parent.