| Hybrid rice technology has greatly improved rice yield through heterosis.At present,hybrid rice technology is mainly three-line method and two-line method.The three lines include cytoplasmic male sterile line(CMS),maintainer line and restorer line.The two lines include photo-thermo-sensitive genic male sterile line and restorer line.Due to the influence of nuclear-cytoplasmic interaction,the three-line method is not free;the fertility of photo-thermo-sensitive genic male sterile lines is easily affected by ambient temperature,which is prone to seed production risk.Therefore,it is urgent to explore and create a new male sterile line in order to solve the technical problems of three-line combination and high risk of two-line seed production.Previous studies have found that the anti-temperature-sensitive sterile line Yn S was hybridized with the traditional two-line sterile line Nongken 58 S and its derivative positive photosensitive sterile line,and it was found that F1 was male sterile at any temperature.Previous studies in our laboratory have found that the interaction of two low-temperature sensitive sterile genes rtms6 and rtms10 of Yn S can lead to this phenomenon of male sterility,which was later named as heterozygous male sterility(HMS).Since HMS is male sterile under any light and temperature conditions and is controlled by nuclear genes,this suggests that the breeding and utilization of HMS has the potential to solve the risk of seed production and has broad application potential.In the early stage of this laboratory,the genetic mechanism of HMS was described,and the hybrid male sterile line 1892 HS was created.However,the practicality of 1892 HS needs to be further evaluated.In this study,1892 HS and its parents were sown in two consecutive seasons in Lingshui and Hefei,Hainan.The main agronomic traits,fertility,flowering habits and outcrossing characteristics were investigated to evaluate the reproductive safety period and breeding potential of 1892 HS.The main results are as follows:(I)The main agronomic characters of hybrid male sterile line 1892 HS were: The plant height was higher(compared with 1892S),the plant type was moderate,the stalk was stout,the ear length was 21.7cm,the total number of grains per ear was 143,and the average sowing time was 1892 F,1892HS,1892 RS and 1892 S in order from small to large.(II)In terms of fertility,1892 HS was more stable than 1892 S.1892HS remained male sterile all the time,and the self-fertilizing rate was 0.The fertility of 1892 S changed from sterile to fertile when the temperature dropped and self-fertilizing,the fruiting rate was32.9%.(III)In terms of outcrossing characteristics,1892 HS is more concentrated than 1892 S.The cumulative flowering amount of 1892 HS was 90.75% at the central flowering stage and 32.12% at the peak;The cumulative flowering amount of the control 1892 S was88.54% in the concentrated flowering period and 28.16% in the peak.The proportion of flowering before noon in 1892 HS was higher than that in 1892 S.The flowering peak of1892 S was from 9:30 to 10:30,and that of 1892 HS was from 10:00 to 11:00.Their total stigma exposure rate is not different.(Ⅳ)1892RS turned fertile on 28 March due to temperature drop and began to produce fruit.When breeding 1892 HS in Hainan,attention should be paid to pollination before March 28,avoid high temperature time. |
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