Si Huamin

Pedigree Analysis of Photoperiod-thermo Sensitive Genic Male Sterile Rice

A great progress has been made in two-line hybrid rice in China. Up to 2010, a total of 427 two-line hybrid combina- tions (cultivars) had been registered. In recent years, two-line hybrid rice has become an important type in rice production in China. Photoperiod-thermo sensitive genic male sterile (PTGMS) lines are the basis of two-line hybrid rice. In this paper, the rela- tionship of 130 PTGMS lines used as parents of registered hybrid combinations and/or with the right of protection of new varieties was analyzed, and 126 of 130 PTGMS lines that the relationship defined were traced back to their original PTGMS lines as a starting point. The pedigree of the 73 PTGMS lines used for producing hybrid combinations with large scale planting and/or the right of protection of new varieties was analyzed in detail, and the breeding methods of the 126 PTGMS lines were analyzed. The relationship between the photoperiod-thermo response type and the pedigree of the PTGMS lines was discussed. We also pro- posed that selecting the proper PTGMS materials by pedigree analysis is as important as photoperiod and temperature controlling for studying the molecular mechanism of photoperiod-thermo response in PTGMS lines. Open sharing of the PTGMS resources has the great significance for accelerating the breeding of new practical PTGMS lines and minimizing the adverse environmental

Determination of critical temperatures and panicle development stage for fertility change of thermo-sensitive genic male sterile rice line ‘5460S’

SummaryThe effect of a 1–5 day low temperature treatment applied at different stages during panicle development on the male sterility of 5460S, a thermo-sensitive genic male sterile rice line (TGMSR), was studied. Before and after the period of low temperature treatments the plants were continuously grown under 14.75 h daylength and 29.6° C average temperature (max. 33° C/min. 29° C) in growth chambers in order to avoid any other possible influences on the male sterility. The results indicate that the plant responses to low temperature was dependant on the developmental stage of the young panicle. The stages from formation of pollen mother cell to late uninucleate of pollen grains were the most sensitive to temperature. It is concluded that the critical temperature for the fertility change from male sterile to partially fertile in ‘5460S’ is about 28.5° C in the sensitive panicle development stages under the condition studied.

The Effect of Thermo-Photo Period for Donor Plant Growth on Anther Culture of Indica Rice

Donor plants of rice (Oryza sativa L. subsp.indica. C.V. Si-Xi-Zhan) were grown in 9 phytotrons with a 3 thermoperiods (average temperature 29.7°C, 25.7°C or 23.5°C) ×3 photoperiods (14.75h, 14.00h or 13.25h) design. It was found that the callus initiation rate was higher if plants grew under mid or short photoperiod and mid or low temperature. The highest one was 42.24% under the condition of 25.7°C/14.00 h. The frequency of green plantlet regeneration was more that 20% under the conditions of 23.5°C or 25.7°C/13.25 h. The ratio of green plantlet to albino was also higher under short photoperiod condition. The suitable season for indica anther culture was discussed.