All hermaphrodite progeny are derived by self-pollinating the sunrise papaya mutant |
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| Authors: | C. Chan-Tai C.-R. Yen L.-S. Chang C.-H. Hsiao T.-S. Ko W. E. Weber |
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| Affiliation: | Taiwan Seed Improvement and Propagation Station;Department of Plant Industry, National Ping-Tung University Science and Technological;Department of Horticultural Science, National Taiwan University, Taipei, Taiwan |
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| Abstract: | Self‐pollination of a hermaphroditic cultivar normally gives a ratio of 2 : 1 hermaphrodite to female papayas with genotypes M2m and mm, respectively. Much effort has been dedicated to marking the sexual types of papaya at the seedling stage to distinguish hermaphroditic from female papayas. A hermaphroditic papaya mutant (SR*) has been obtained, derived from the ‘Sunrise’ papaya cultivar mutant. Self‐pollination of the mutant resulted in all progenies being hermaphroditic. The genotype of the female was lethal, as a result of a lethal gene being linked to the mm female gene complex in this case. However, a 3 : 1 segregation ratio was obtained from the progeny of the hermaphroditic cultivar ‘Thailand’ crossed with SR*, indicating that all genotypes survived. Homozygous genotypes (M2M2) would be lethal according to Storey's model. Randomly selected F1 plants of the ‘Thailand’ SR* combination were self‐pollinated to obtain an F2 generation. The F2 segregation ratio suggested that the SR* mutant had a different form of the M2 allele, now designated as M@, which allowed the dominant M@M2 to survive in cross combinations. Genetic study has proved that SR* has the M@ml genotype, a new mutant. It is capable of producing all hermaphroditic papaya progenies. |
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| Keywords: | Carica papaya hermaphroditic mutant sexual type |
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