Production of Intergeneric Hybrids between the C3-C4 Intermediate Species Diplotaxis tenuifolia (L.) DC. and Raphanus sativus L.

Abstract

In intergeneric crossings between Diplotaxis tenuifolia (2n = 22, DtDt) and five cultivars of Raphanus sativus (2n = 18, RR), an intergeneric F 1 hybrid was produced from the crossing of D. tenuifolia × R. sativus cv. '4-season leaf' through ovary culture followed by embryo culture. The induced amphidiploid (2n = 40, DtDtRR) showed well-regulated meiotic features at PMCs and a high pollen fertility (75 %). Three BC 1 hybrids with DtRR (2n = 29) or DtDtR (2n = 31) genome constitutions were obtained by the same embryo rescue procedure in the crossings of amphidiploid × R. sativus and D. tenuifolia × amphidiploid, respectively. In the successive backcrossings of two BC 1 hybrids (DtRR, 2n = 29) to R. sativus, 102 BC 2 hybrids were obtained by conventional pollination. In the reciprocal crossing of R. sativus × BC 1 hybrids, 12 reciprocal BC 2 hybrids were also produced without embryo rescue. The somatic chromosome number of 89 BC 2 hybrids with D. tenuifolia cytoplasm and 12 reciprocal BC 2 hybrids with R. sativus cytoplasm ranged from 2n = 18 to 2n = 23 that were estimated to carry 2n = 18 chromosomes of R. sativus and zero to five chromosomes of D. tenuifolia. Among them, 24.7 % of the BC 2 hybrids and 41.6 % of the reciprocal BC 2 hybrids were assumed to be monosomic addition lines (MALs, 2n = 19). The novel intergeneric hybrids obtained in this study could become useful materials for investigating the genetic effects on C 3 -C 4 intermediate traits at the genomic and chromosomal levels, as well as for estimating the performance of genetic improvement in Brassicaceae.

Inheritance of C3―C4Intermediate Photosynthesis in Reciprocal Hybrids BetweenMoricandia Arvensis(C3―C4) andBrassica Oleracea(C3) That Differ in Their Genome Constitution

“…These C 3 -C 4 intermediate species reduce photorespiration by the glycine-decarboxylation system without adding a C 4 cycle (Monson and Rawsthorne, 2000;Ueno et al, 2003). In this family, interspecific and intergeneric crosses are relatively easier to achieve than in other families (e.g., Bang et al, 1996Bang et al, , 2003reviewed in Matsuzawa et al, 1996). As a result, studies of artificial hybridization between C 3 and C 3 -C 4 intermediate species in this family have been attempted to genetically improve carbon and water economies by the introduction of C 3 -C 4 intermediate characteristics into C 3 plants (Apel et al, 1984;O' Neill et al, 1996;Razmjoo et al, 1996;Rawsthorne et al, 1998;Yan et al, 1999;Zhang et al, 2004).…”

Some Perspectives on Rocket as a Vegetable Crop: A Review

“…These species hybridize with other members of respective genera through sexual reproduction, ovary culture, embryo culture and protoplast fusion (Salisbury 1989, Fahleson et al 1997. Intergeneric hybrids have also been produced between perennial wall rocket and annual garden rocket, suggesting that there is a high level of genetic similarity between the species (Harberd & McArthur 1980, Bang et al 2003.…”

Evidence from Photosynthetic Characteristics for the Hybrid Origin of Diplotaxis muralis from a C3‐C4 Intermediate and a C3 Species

“…The C 3 -C 4 intermediate species occur in the genera Moricandia, Diplotaxis, and Brassica and perform C 3 -C 4 intermediate photosynthesis without the C 4 cycle (Hunt et al, 1987;Apel, 1996;Apel et al, 1997;Ueno et al, 2003). Artificial intra-and inter-generic hybridizations have been successfully carried out between C 3 -C 4 intermediate species and C 3 species in this family (Apel et al, 1984;Bang et al, 1996;O'Neill et al, 1996;Rawsthorne et al, 1998;Yan et al, 1999;Bang et al, 2003;Ueno et al, 2003). The genus Diplotaxis consists of 27 species, which are distributed through Europe and the Mediterranean region (Willis, 1985).…”