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Mitochondrial markers can be used to differentiate diverse mitotypes as well as cytoplasms in angiosperms. In cauliflower, cultivation of hybrids is pivotal in remunerative agriculture and cytoplasmic male sterile lines constitute an important component of the hybrid breeding. In diversifying the source of male sterility, it is essential to appropriately differentiate among the available male sterile cytoplasms in cauliflower. PCR polymorphism at the key mitochondrial genes associated with male sterility will be instrumental in analyzing, molecular characterization, and development of mitotype-specific markers for differentiation of different cytoplasmic sources. Presence of auto- and alloplasmic cytonuclear combinations result in complex floral abnormalities. In this context, the present investigation highlighted the utility of organelle genome-based markers in distinguishing cytoplasm types in Indian cauliflowers and unveils the epistatic effects of the cytonuclear interactions influencing floral phenotypes. In PCR-based analysis using a set of primers targeted to orf-138, 76 Indian cauliflower lines depicted the presence of Ogura cytoplasm albeit the amplicons generated exhibited polymorphism within the ofr-138 sequence. The polymorphic fragments were found to be spanning over 200–280 bp and 410–470 bp genomic regions of BnTR4 and orf125, respectively. Sequence analysis revealed that such cytoplasmic genetic variations could be attributed to single nucleotide polymorphisms and insertion or deletions of 31/51 nucleotides. The cytoplasmic effects on varying nuclear-genetic backgrounds rendered an array of floral abnormalities like reduction in flower size, fused flowers, splitted style with the exposed ovule, absence of nonfunctional stamens, and petaloid stamens. These floral malformations caused dysplasia of flower structure affecting female fertility with inefficient nectar production. The finding provides an important reference to ameliorate understanding of mechanism of cytonuclear interactions in floral organ development in Brassicas. The study paves the way for unraveling developmental biology of CMS phenotypes in eukaryotic organisms and intergenomic conflict in plant speciation.

Existence of genetic divergence, appropriate characterization of breeding lines for economically important traits and determining parents with favourable alleles is the crux of crop genetic improvement programmes. This study is the first report of unravelling genetics and potential of petaloid-type cytoplasmic male sterile (pt-CMS) lines in carrot. Ten pt-CMS lines were crossed with 10 inbreds in line × tester mating fashion to generate 100 testcross progenies. Nutritional profiling of the 100 testcrosses progenies along with 20 parental types was carried out for two consecutive years for eight important traits to identify superior combiners. The pooled analysis revealed that the carotenoid content in root is under the genetic control of major genes (oligogenic). The pooled analysis revealed less than unity value of σ2A/D and σgca2/σsca2 for majority of the traits depicting preponderance of non-additive gene effects. The pt-CMS lines KT-28A, Kt-62A, KT-80A and KT-95A were identified as good combiners for carotenoids. The cross combination, KT-98A × KS-50 identified as the best heterotic combiner for CUPRAC and FRAP content over the years. Similarly, the combinations, KT-62A × KS-21, KT-80A × New Kuroda and KT-62A × KS-59 were found promising across the years for developing nutritionally rich F1 hybrids. The interaction analysis among the different antioxidant traits and plant pigments unveiled the scope of simultaneous improvement.

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Background: Mitochondrial markers can be used to differentiate diverse mitotypes as well as cytoplasms in angiosperms. In cauliflower, cultivation of hybrids is pivotal in remunerative agriculture and cytoplasmic male sterile lines constitute an important component of the hybrid breeding. Thus, the breeders look for utilizing diverse male sterile cytoplasms in hybrid progamme. In diversifying source of male sterility,it is essential to appropriately differentiate among the available male sterile cytoplasms in cauliflower.PCR polymorphism atthe key mitochondrial genes associated with male sterility will be useful in developing mitochondria specific markers for the different male sterile cytoplasms. Also, the auto and alloplasmic cytonuclear combinations result in complex floral abnormalities.Thus, the study aimed at developing mitotype specific markers of the sterile cytoplasms and to unravel thegenetic effects of the cytonuclear interactions on flower morphology in Indian cauliflowers.Results: In PCR based analysis using a set of primers targeted to orf-138, 76 Indian cauliflower lines showed presence of Ogura cytoplasm though amplicons showed polymorphism within the ofr-138 sequence. The polymorphic loci were found to be spanning over 200-280 bp and 410-470bp genomic regions of BnTR4 and orf125, respectively. Sequence analysis revealed that such cytoplasmic genetic variations could be due to single nucleotide polymorphisms and insertion or deletions of31/51 nucleotides.The cytoplasmic effects on varying nuclear-genetic backgrounds led to varying degree of floral malformations ranging from reduction in flower size, stamens and style length, modification in position of styleand anthers, absence of non-functional stamens to other floral abnormalities. These floral malformations caused dysplasia of flower structure affecting female fertility and inefficient nectar production.Conclusions: The mitochondria specific markers can distinguish ogurabased male sterile cytoplasm. Large number of Indian cauliflower lines showed mitotype variations even within the ogura based cytoplasm. Variable nucleo-cytoplasmic interactions resulted into diverse type of floral malformationsin addition to pollen sterility even within the group of ogura based CMS lines. The finding provide important reference ameliorate understanding of mechanism of cytonuclear interactions in floral organ development in Brassicas. The study will help the breeders in selecting CMS lines without any floral abnormalities in B. oleracea.