| Co-Investigator(Kenkyū-buntansha) |
INDEN Haruhisa Miyazaki University, Faculty of Agriculture, Professor, 農学部, 教授 (60151768)
MURAKAMI Kenji Okayama University, The Graduate School of Natural Science and Technology, Lecturer, 自然科学研究科, 講師 (40200266)
KATO Kenji Okayama University, Faculty of Agriculture, Associate Professor, 農学部, 助教授 (40161096)
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| Research Abstract |
Male sterile tomato mutant "T-4" with intact pollen or without collapsed pollen was induced by irradiation of the seeds with γ-rays. Pollen viability of "T-4" due to partial fertility restoration was investigated using male sterile mutant "T-3", with perfectly collapsed pollen, as a T-4 pollen recipient. Furthermore, mode of inheritance of male sterility and molecular marker linked to T-4 sterile gene(s) were determined.
A few fruits with many seeds were observed during late September to late October, and late January to late April. Parthenocarpic fruits were observed on T-4 plants at low temperature during late October to early March. Male fertility restoration was greater at night temperature of 8℃than of 24℃, which suggested that low temperature stimulated pollen fertility restoration. In this case, self pollination was carried out by smear method. The extent of natural self-pollination was not evident, and remains a subject for the future.
When heterozygous plants were selfed in six
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trials, fertile and sterile progenies segregated at a ratio 13 : 3, which suggested an involvement of fertility inhibiting gene. Fertility inhibiting gene (I) was postulated to induce male sterility in a case of homozygous recessive fertile gene "ff".
On the other hand, RAPD analysis was carried out for the development of molecular markers closely linked to male sterile gene(s) of "T-4", resulting in the establishment of two markers, CMN-B30 1700 bp and CMN-B50 352 bp, both of which linked with ms gene by 8.4 cM. A RAPD band of CMN-B50 352 bp was sequenced and successfully converted to an STS marker, which can be practically utilized as a selection marker. AFLP analysis was also carried out, and a total of six polymorphic bands were detected between "First" and "T-4".
From the segregation ratio mentioned above, it seems that two genotypes, a sterile type ffII and a fertile type ffii are expected. The genotype obtained from crossing them is ffIi, which is male sterility. This genotype is able to use as a mother parent for F_1 seed production. Currently, our focus is on determination of possible existence of two types of male sterility, ffII and ffIi. Less
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