Microspore embryogenesis and production of haploid and doubled haploid plants in carrot (Daucus carota L.)

Jin-Rong Li,Fei-Yun Zhuang,Zhi-Wei Zhao,Cheng-Gang Ou,Hong Hu,Ji-Hua Mao

doi:10.1007/s11240-012-0235-5

Jin-Rong Li, Fei-Yun Zhuang + Show 4 more

Open Access

https://doi.org/10.1007/s11240-012-0235-5

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Abstract

Protocols were developed for the generation of haploid and doubled haploid plants from isolated microspores of carrot (Daucus carota L.). Forty-seven carrot accessions, including six inbred lines, 11 cultivars, 20 F1s, two BC1F1s, four F2s, one F3, and three F4s, were screened to evaluate the genotype influence on isolated microspore embryogenesis over 4 years. Twenty-eight accessions responded by producing embryos and/or calli. A cytological analysis showed that two modes of carrot microspore embryogenesis exist: an indirect route via calli (C mode), and a direct route via embryos (E mode). Eleven accessions were in the C mode, and 17 were in both modes. The highest production rates were in 10Y25 (a European Nantes cultivar) with 27 calli and 307 embryos, and 100Q6 (a semi-Nantes F1 hybrid) with 176 calli and 114 embryos. The time period to produce embryos or calli differed significantly between 2 and 6 months. Cold and heat pretreatment generally had a negative impact on the induction of microspore embryogenesis, but a short pretreatment showed a positive influence on some accessions. Twenty-eight lines regenerated plants from the primary individual embryos or calli of three accessions were established to analyze the ploidy level. The percentage of spontaneous diploidization showed very wide differences among the accessions and lines. Differences in leaf color intensity, leaf size, and leaf dissection were found among haploid, doubled haploid, and triploid plants.

Highlights

Carrot (Daucus carota L.) is an out-crossing biennial species, and one of the most economically important vegetable crops worldwide (Peterson and Simon 1986)
Protocols were developed for the generation of haploid and doubled haploid plants from isolated microspores of carrot (Daucus carota L.)
Cold and heat pretreatment generally had a negative impact on the induction of microspore embryogenesis, but a short pretreatment showed a positive influence on some accessions

Summary

Introduction

Carrot (Daucus carota L.) is an out-crossing biennial species, and one of the most economically important vegetable crops worldwide (Peterson and Simon 1986). The vigor of early-generation carrot inbred lines selected from open-pollinated cultivars decreases dramatically due to inbreeding depression (Peterson and Simon 1986). A doubled haploid (DH) line is valuable for crop breeding programs because traits are fixed without multiple self-pollinating generations. It was first envisioned as a technique to accelerate the breeding process and to use for practical and basic research in many crops (Dunwell 2010; Ferrie and Caswell 2010; Germana 2011). While efficient protocols for microspore embryogenesis induction have been developed to obtain haploid and DH plants in several crops (Maluszynski et al 2003; Dunwell 2010; Ferrie and Caswell 2010), limited progress has been reported using anther cultures (Dohya et al 1997; Tyukavin et al 1999; Adamus and Michalik 2003; Gorecka et al 2005; Smykalovaet al. 2009;), isolated microspore cultures (IMC; Dohya et al 1997; Gorecka et al 2010; Ferrie et al 2011), or

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