Morphologic, cytogenetic, and enzymatic variation in tissue culture regenerated plants of apomictic old-world bluestem grasses (Bothriochloa sp.)

Abstract

Somaclonal variant plants may be of use in broadening the germplasm base of plant species and providing useful stocks for cytogenetic investigations. This study was conducted to compare morphologic, cytogenetic and enzymatic characteristics of 21 R~ (initial regenerate) bluestem, Bothrioehloa sp., plants, visibly identified in a field-grown population of 522 plants as probable variants, with their respective R 0 (explant donor) progenitor. An R, seedling population was grown to ascertain the transmission of the variant R~ phenotypes. All R~ plants differed from their respective Ro progenitors in one or more morphological characters. Foliage colour was the most pronounced difference in most cases. Four of the plants, three of which were dwarfed, produced no inflorescences. The R, plants tended to be shorter than R 0 progenitors and had corresponding decreases in lengths on inflorescences and lowest racemes. All R, plants of accessions 8911C and 8793 had an increase in chromosome number from 2n = 4x = 40 to 2n = 5x = 50. Three dwarfed Rh plants, derived from accession 8873B, were aneuploids, two having 2n = 48 chromosomes and the third being a probable mixoploid with 55-58 chromosomes. Other plants of accession 8873B had the R0 chromosome number. Fertility, as estimated by pollen stainability and seed set, generally was reduced in R, plants relative to the R 0. This reduction was not drastic, however, with all flowering plants having 45% or higher seed set. Apomixis apparently maintained fertility in all R~ plants, including those with a pentaploid chromosome number. All R t plants differed from their respective R 0 plants in peroxidase and esterase banding patterns. All R t plants of accessions 891 IC, and 8793, respectively, had identical peroxidase and esterase bands. For both enzyme systems two banding patterns were present in R~ plants of accession 8873B, with 12 of 13 plants exhibiting common patterns. Examination of R 2 progeny plants confirmed the genetic transmission of the variant phenotypes and, by virtue of uniformity, indicated apomictic reproduction in the R~ plants. The results demonstrate the production of potentially useful genetic and cytogenetic variant plants via tissue culture in these apomictic species.

Regeneration and somaclonal variation in apomictic Paspalum dilatatum Poir

“…The expression of somaclonal variation in apomictic grasses appears to be species dependent. Taliaferro et al (1989) reported variability in regenerants of two Bothriochloa species but Hanna et al (1984) did not find variability in regenerants of apomictic Panicum maximum Jacq.…”

Clonal Variation in Cereals and Forage Grasses

“…Davies and Cohen (1992) found alterations in apomictic seed production among dallisgrass somaclones, and progeny derived from some somaclones were not uniform in phenotype. In contrast, Taliaferro et al, (1989) found uniform expression of somaclonal variation in the progeny of somaclones, confirming genetic transmission of somatic variation in floral morphology, plant height, foliage colour, and fertility in apomictic bluestem (Bothriochioa sp.) somaclones.…”

Somatic Embryogenesis and Synthetic Seed II

“…comm.). These grasses exhibit an apomictic mode of reproduction (Taliaferro et al 1989). These grasses exhibit an apomictic mode of reproduction (Taliaferro et al 1989).…”

“…An alternate approach for the improvement of crop plants, especially the apomicts (Taliaferro et al 1989) is to select tissue culture-induced mutants or somaclonal variants showing useful characters. In our laboratory, attempts are now in progress to develop a genetic transformation protocol in which transgenic Caucasian bluestem plants can be regenerated using this rapid regeneration system.…”