Studies On Intergeneric Somatic Hybridization Between Brassica Napus L. And Descurainia Sophia By Protoplast Fusion

Cruciferous species Descurainia Sophia, has excellent tolerance to various stresses,also has more than 38 % content of linolenic acid in its seeds which may be sources ofedible oil for health care. So we designed to research D. Sophia for germplasmenhancement by protoplast culture of D. Sophia and protoplast fusion between Brassicnapus L. and D. Sophia. Results were as follow:1. Studies on protoplast culture of Descurainia SophiaCalli of Descurainia Sophia, pretreated in low temperature and dark for 24h,were usedto isolate protoplast for highest yield, formulated efficent protoplast-culturing system.Results showed that appropriate enzyme combination among all combinations designed forisolating protoplast was 5%Cellulase+0.5% Macerozyme+5mmol/L MES; Improved B5media was the best for culturing protoplast with density 1×10⁵ among B5,Km8p and MSliquid media; Appropriate media for regenerating from the calli was MS+2.0 mg/L6-BA+0.2mg/L NAA+1.7mg/L AgNO₃; Appropriate rooting media was MS+0.5 mg/L IBA+0.5mg/L NAA; Also, low-temperature treatment of calli was also very important forobtaining qualified protoplast.2. Production of symmetric hybrids between Brassic napus L. and Descurainia sophiautilizing an efficient protoplast-fusion systemHigh yield of protoplast isolation was achieved from leaves of Descurainia sophia andcotyledons of B. napus L..The isolated protoplasts were used for the establishment of anefficient protoplast-fusion system between the two cruciferous species.The best enzymecombination for isolating protoplast from D. sophia and B. napus was 4%Cellulase+0.5%Macerozyme+5 mmol/L MES and 1% Cellulase+0.2% Macerozyme+3 mmol/L MES,respectively.Using PEG-DMSO metheod, fusion percentage of 10.0% was obtained.Modified B5 liquid media was the best for the culture of fused cells among the three B5,MS and Km8p liquid media.Change of culture media at frequent intervals helped overcomebrowning of culture.The best media for shoot regeneration from calli was MS+4.0 mg/L6-BA+0.3mg/L NAA+5.0mg/L AgNO₃, and the best rooting media was MS+0.1 mg/L IBA+0.1mg/L NAA.19 somatic fusion hybrids between B.napusL. and D. Sophia wereobtained.3. Morphology and cytogenetics of the intergenus somatic hybridsSomatic fusion hybrids between B. napus L. and D. Sophia were transplanted to thefield, then morphological, cytogenetical observations were conducted. Hybrids grew slowly,with average height, 100.8 cm. Their leaf type was more similar to B. napus L, but leafedge liked D. Sophia; Their buds were purple ,small and wizened like D. sophia; Comparedwith parents, their flowering and maturation were later, and their flowers smaller, but yellowas in B. napus L, the vivid pollen percentage was 34.3%. Their yielding seeds was alsolower, with average seed number per silique, 6.5. Chromosome counting at stage of meiosisprophaseâ…¡, showed 66. Totally, morphological and cytogenetic identification showed thatthe plants created by protoplast fusion, may be new germplasm beneficial to B. napus andD. Sophia.