<p><strong>Background: </strong>In the case of chrysanthemums, a commercially important ornamental plant, understanding of combining ability can significantly improve breeding efficiency, allowing for the development of new cultivars with desired traits such as better flower quality, longer shelf life, disease resistance and adaptability to different environmental conditions. Combining ability is a powerful tool in chrysanthemum breeding, enabling breeders to make informed decisions about which parent plants to use for creating hybrids with desired traits. By focusing on GCA and SCA, breeders can enhance traits like flower size, color, disease resistance and environmental adaptability, leading to the development of superior chrysanthemum varieties for both ornamental and commercial purposes. An experiment was carried out in the research plot of Department of Floriculture and Landscaping, OUAT, Bhubaneswar Odisha to study the combining ability effects in chrysanthemum.<br />
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<strong>Methods: </strong>Eight varieties of chrysanthemum were crossed using half-diallel mating design (excluding reciprocals). After crossing, 28 number of hybrids were produced which were studied for combining ability.<br />
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<strong>Result: </strong>Shova and SS were reported to be the best general combiners for flower yield attributes, while the hybrids Shova x Arka Kirti, Shova x UHFS-56, SS x A.Kirti , Shova x ACC-1, Shova x SS&nbsp; were found to have significant desirable SCA effects for number of flowers per plant.</p>


<p>Evaluation of Combining Abilities for Traits Improvement in Chrysanthemum</p>


<div style="text-align: justify;">An experiment was conducted to study the effect of graded concentrations of foliar applied growth retardants (cycocel and B-nine) on the growth and flowering of Chrysanthemum morifolium cv. Flirt. Uniform rooted cuttings raised in pot soil culture received spray applications of growth retardants viz., cycocel and B-nine prepared in 0.1% Tween 80. Cycocel was applied at 1000, 2500 and 5000 mgL-1, whereas B-nine was applied at 100, 250 and 500 mgL-1 concentrations. Plants were sprayed at 2 and 6 weeks after transplantation. Visual observations, plant height, fresh mass, dry mass, number of laterals, number of inflorescences and inflorescence diameter were recorded at periodic intervals. Cycocel treated plants recorded a significant increase in fresh and dry mass of whole plants, leaves and roots, whereas B-nine treated plants were comparable with the controls. Cycocel and B-nine treated plants showed early emergence of buds and inflorescences, whereas no significant effect was recorded on number of laterals. Cycocel application resulted in the increase in inflorescence number. The present results suggest that the treatment effect may be cultivar dependant as many other cultivars of chrysanthemums have been chemically tailored with desired effects using cycocel and B-nine.</div>

Effect of growth retardants on the growth and flowering of <em>Chrysanthemum morifolium</em> cv. Flirt<br />&nbsp;

<div style="text-align: justify;">TSV isolates (GNAP7. SFAP17 and CUKA13) maintained on cowpea were cross inoculated on five popularly grown varieties and hybrids of groundnut (JL-24, K-6, Prasuna, K-9, Kadiri harithandra), sunflower (KBSH-44, DRSH-1, NDSH-1012, Mordent, Sunbred-275) and cucumber (Long green, Poorna, Ageti, Sheetal, Uday). Incubation period required for the initiation of local and systemic symptoms varied among different hosts and cultivars. Local symptoms of veinal necrosis, leaf yellowing and wilting, petiole necrosis, chlorotic spot, tip necrosis and systemic symptoms of mosaic, wilting, necrotic streaks on stem, bud necrosis, axillary shoot proliferation were observed in different hosts and Culivars. Out of 23 plant species tested against TSV by sap inoculation, 15 plant species were susceptible to TSV, which includes Beta vulgaris, Abelmoschus esculentus, Cicer arietinum, Solanum melongena, Ricinus communis, Chrysanthemum indicum, Phaseolus vulgaris, Gerbera jamesonii, Macrotyloma uniflorum, Vigna unguiculata subsp. unguiculata, Tagetus erecta, Allium cepa, Phaseolus coccineus, Solanum lycopersicum, Vigna unguiculata ssp. sesquipedalis.&nbsp;</div>

Evaluation of Combining Abilities for Traits Improvement in Chrysanthemum

Effect of growth retardants on the growth and flowering of Chrysanthemum morifolium cv. Flirt

Biological characterization and host range of Tobacco Streak Virus (TSV)