Effects of chloroplast substituted Ogura male sterile cytoplasm on the performance of cauliflower (Brassica oleracea var. botrytis L.) F1 hybrids

Introgression of Ogura cytoplasm into Brassica oleracea initially resulted in leaf yellowing at low temperature. It was later on corrected through chloroplast substitution. However, the effect of improved Ogura cytoplasm on performance of cauliflower F1 hybrids is not known. We report for first time the effect of corrected Ogura cytoplasm on vegetative, commercial and physiological traits of cauliflower. Six F1 hybrids based on 3 CMS lines were compared with their respective isogenic male fertile analogs. Vigor and maturity was improved in few and remained unaltered in most of the Ogura based hybrids when compared with their male fertile analogs. Ogura cytoplasm had no significant influence on commercial yield. Curd shape and size also remained unaltered in the Ogura based F1 hybrids. Curd compactness and color were similar in both male sterile hybrids and their fertile analogs. Similar results were also recorded for important physiological non-parasitic disorders. Ogura cytoplasm based hybrids and their male fertile analogs were free from riceyness, fuzziness, leafiness and any kind of undesirable pigmentation. Difference between male sterile hybrids and respective fertile analogs were mainly due to genotype specific nuclear-cytoplasmic interactions. These results were in contrary to earlier reports of adverse effect of Ogura cytoplasm (prior to chloroplast substitution) on the performance of cauliflower and cabbage F1 hybrids. Thus, the refined Ogura cytoplasm can be extensively utilized for development of quality cauliflower hybrids with higher productivity.