• Journal of the Korean Society of Tobacco Science
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• v.22 no.1
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• pp.71-75
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• 2000

The genetic makeup could be the most important among many factors affecting yield and quality of tobacco(Nicotiana tabacum L.). The mammoth gene found in N. tabacum is associated with greater leaf number and poor leaf quality. This study was carried out to obtain the basic information about the inheritance of mammoth gene and white flower color. Two flue-cured breeding lines, KF 9373-2 and KF 8832-85, F$_1$, F$_2$, two parents backcrossed with F$_1$, and F$_3$ lines derived from cross of above two lines were investigated for flowering type(mammoth gene) and flower color. All plants of F$_1$ population revealed normal flowering type and pink flower color. The progeny of F$_2$ generation was segregated into the phenotypic ratio of 9 : 3 : 3 : 1 with normal flowering type and pink flower color, normal and white, non flowering type(NF) and pink, and NF and white, respectively. Among the progenies of back-crossing populations, the flowering type showed a segregation ratio of 1 : 1 as normal and NF in BP$_1$ and flower color did also 1 : 1 as pink and white in BP$_2$. All lines have the mammoth gene in F$_3$. that were selected in F$_2$ progeny as non flowering. But 9 lines among 14 were segregated with 3 : 1 as pink and white flower in F$_3$. which were selected in F$_2$ as pink flower color. These results indicated that the characters of mammoth gene and white flower were controlled by a pair of recessive genes, respectively.

• Proceedings of the Botanical Society of Korea Conference
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• 1996.07a
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• pp.4-9
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• 1996

The majority of plants sense environmental signals, such as day length or temperature, to select their transition timing from vegetative growth t flowering. Here, we report the identification of a regulatory gene, OsMADS1, that controls the photoperiod sensitivity of flowering time. Constitutive expression of OsMADS1 in a long-day flowering plant, Nicotiana sylvestris, resulted in flowering in both short-day long-day conditions. Similarly, ectopic expression of the gene in a short-day flowering plant, N. tabacum cv. Maryland Mammoth, also induced flowering regardless of the day length. The transition time was dependent on the level of the OsMADS1 transcript in transgenic plants. These suggest that OsMADS1 is a key regulatory factor that determines the transition from shoot apex to floral meristem and that it can be used for controlling flowering time in a variety of plant species.