Xiao Ying-hui

Thoughts and Practice on Some Problems about Research and Application of Two-Line Hybrid Rice

The main problems about research and application of two-line hybrid rice were reviewed, including the confusing nomenclature and male sterile lines classification, the unclear characteristics of photoperiod and temperature responses and the unsuitable site selection for male sterile line and hybrid rice seed production. In order to efficiently and accurately use dual-purpose genic male sterile lines, four types, including PTGMS (photo-thermo-sensitive genic male sterile rice), TGMS (thermo-sensitive genic male sterile rice), reverse PTGMS and reverse TGMS, were proposed. A new idea for explaining the mechanism of sterility in dual-purpose hybrid rice was proposed. The transition from sterile to fertile was involved in the cooperative regulation of major-effect sterile genes and photoperiod and/or temperature sensitive ones. The minor-effect genes with accumulative effect on sterility were important factors that affected the critical temperature of sterility transfer. In order to make better use of dual-purpose lines, the characterization of responses to photoperiod and temperature of PTGMS should be made and the identification method for the characterization of photoperiod and temperature responses of PTGMS should also be put forward. The optimal ecological site for seed production could be determined according to the historical climate data and the requirements for the meteorological conditions during the different periods of seed production.

Physiological and biochemical characteristics in flag leaves of the C Liangyou series of hybrid rice combinations at late growth stages.

The contents of chlorophyll, soluble sugars, soluble proteins and thiobarbituric acid reaction substance (TBARS), chlorophyll fluorescence parameters, net photosynthetic rate as well as the activities of superoxide dismutase (SOD) and peroxidase (POD) of flag leaves at the late growth stages were studied by using C Liangyou series of hybrid rice combinitions as material and Shanyou 63 as control. The C Liangyou series of hybrid rice combinations used in the experiment included C Liangyou 396, C Liangyou 87, C Liangyou 755 and C Liangyou 34, which all used C815S as male sterile line. The contents of chlorophyll, soluble sugars and soluble proteins in flag leaves of the C Liangyou series combinations at the late growth stages were higher than those of the control, whereas the TBARS content was lower than that of the control. The activities of SOD and POD were significantly higher than those of the control on the 7th day after heading, and then decreased slowly. ΦPSII value and qP value of flag leaves decreased at the late growth stages, and these two parameters in flag leaves of the C Liangyou series combinations were higher than those of the control, while the qN value increased at the late growth stages and was lower than that of the control. The net photosynthetic rate of flag leaves at the late growth stage was higher compared with the control. These results suggest that slow senescence and strong photosynthetic capability in flag leaves at the late growth stages are the physiological basis of the C Liangyou series combinations.

On combining ability and utilization of C815S male sterile lines

The combining ability of 9 agronomic characters in F1was studied with 5 male sterile lines and 7 restorer lines by the way of p×q incomplete dual cross (NCⅡ) design. The result was that the general combining ability(GCA) of C815S was the best compared with dual-purpose genetic rice male sterile LongS, 7Guang S052, Peiai64S and CMS LineⅡ-32A. The GCA of the effective tillers number, total grain number, grain density, yield per plant and economic coefficient of C815S was 6.656, 6.342, 7.236, 16.669 and 6.705 respectively. It was ranked at first in the examined dual-purpose male sterile lines. The GCA of the seed setting rate and 1 000-grain weight were 0.329 and 2.353, respectively, which was ranked the 2nd. The GCA of plant height was-2.197, and it was ranked the fourth. The larger variance of specific combining ability was found in effective spikes and grain yield per plant of C815S. The effective spikes, grain density, 1 000-grain weight, grain yield per plant, the economic coefficient of 5 traits were classified into class Ⅰa nd classⅡin per panicle and seed setting rate, and classified into class Ⅳi n plant height and spike length.