Regeneration potential of CIMMYT durum wheat and triticale varieties from immature embryos

Abstract

Twenty‐five durum wheat elite advanced lines and released varieties, and five triticale varieties were evaluated for their ability to produce embryogenic callus using three different media. For callus initiation and maintenance there were basal Murashige and Skoog (MS) medium containing double strains of macroelements and 2.5 mg/l 2,4D (DW1), basal MS medium containing 2.0 mg/l 2,4D (DW2), or basal MS medium supplemented with 1.0 mg/l 2,4 D and coconut milk (DW3). Plant regeneration was achieved on basal MS medium with indoleacetic acid and 6‐benzylaminopurine, and plants rooted on MS with 1‐naphthale‐neacetic acid. DW3 medium proved better than the other media tested for embryogenic callus initiation and maintenance. Regeneration rates varied widely with both genotype and initiation medium, with values ranging from no regeneration to 100% regeneration; the plantlets produced per embryo ranged from five to 20. Fourteen of the durum wheat genotypes showed 63–100% regeneration from DW3 callus formation medium, four lines from DW1 medium, and two lines from DW2. Four of the triticale varieties had regeneration of 48–100% from DW3 medium. After six subcultures, over a 6‐month period, genotypes lost their ability to regenerate plants. Only 10 lines retained some plant regeneration potential but regeneration was at reduced levels. Successful regeneration of durum wheat and triticale varieties will be used as an integral part of the transformation process.

Tissue culture efficiency of wheat species with different genomic formulas

“…Wheat includes more than 20 cultivated species (Goncharov 2011), however substantial research effort has been dedicated mainly to durum and bread wheat, owing to their prevalence in the world production (Fennel et al 1996, Machii et al 1998, Barro et al 1999, Bohorova et al 2001, He and Lazzeri 2001, Zale et al 2004, Vendruscolo et al 2008, Yin et al 2011. Until recently, many wheat species were not analyzed for plant regeneration ability in vitro; but nowadays, the interest in such studies is on the rise (Chang et al 2012, Yang et al 2015, Özgen et al 2015.…”

“…al 1998, Barro et al 1999, Bohorova et al 2001, He and Lazzeri 2001, Pellegrineschi et al 2002, Eudes et al 2003, Vendruscolo et al 2008, Miroshnichenko et al 2013) and for reliable and efficient genetic engineering (Mamrutha et al 2014, Jones 2015. However, the cultivation of donor plants to ensure a regular supply of immature embryos is labor-intensive and requires a lot of time and space.…”

“…For example, the application of the alternative 5-step protocol proposed by Eudes et al (2003) involved a much larger number of media components/ growth regulators and resulted in satisfactory plant regeneration induction from scutellum of T. monococcum, T. durum and T. aestivum, without callus phase. There are numerous reports that describe the substantial increase in regeneration response in cultures of hexaploid bread wheat with AABBDD genome by modifications of the medium composition (Fennel et al 1996, Machii et al 1998, Barro et al 1999, Bohorova et al 2001, He and Lazzeri, 2001, Chauhan et al 2007, Vendruscolo et al 2008, Miroshnichenko et al 2013. However, in most of the cited publications, the different manipulations were frequently inefficient in overcoming the strong genotypic effect and many varieties had to be screened to detect responsive wheat genotypes.…”

Callus induction and plant regeneration from immature embryos of Brachypodium distachyon with different chromosome numbers

“…The results mentioned above suggest that at least three different stages, probably controlled by different genetic systems, must be passed through in the regeneration of Brachypodium plants: callus induction, plant regeneration, and green plant production (Chowdhury et al 1991, Bohorova et al 2001.…”

“…Immature embryos, mature embryos or leaf base segments are the most common starting material for establishing embryogenic calli of cereals and grasses and subsequent plant regeneration (Bohorova 2001, González et al 2001, Dahleen and Bregitzer 2002, Eudes et al 2003, Dabul et al 2009, Li et al 2009, Ozbay and Özgen 2010. Currently, procedures are available that permit the in vitro culture of genetically modified Brachypodium.…”