Characteristics And Application Evaluation Of M20S Of Two-line Male Sterile Line Of Large Panicle Type

Two-line hybrid rice has become an important way to utilize heterosis due to its advantages such as simple procedure,free combination and no cytoplasmic negative effect,etc.It is a major trend to use the heterosis between subspecies to produce super hybrid rice with large panicle,many grains and excellent quality.It is a main trend to develop super hybrid rice with large panicle and good quality by using heterosis between subspecies.M20S is a two-line male sterile line of large panicle type,with a single panicle weight of 7～8 g,and a relatively good panicle character,with the potential of early maturity and high yield.The main agronomic traits,heterocrossing performence,critical sterile inducing temperature(CSIT),heterosis and combining ability,rice quality and other aspects of M20S were investigated and studied in order to provide a theoretical basis for the breeding,hybrid seed production and quality improvement of the sterile line and accelerate the production and application of M20S as well as its hybird combination.The research results show that:(1)the number of main stem leaves of M20S is 13,the number of tillers of M20S is small(10 on average);M20S stem stout,large biomass,good panicle character;M20S seedling root traits were good;The sowing period of M20S in guangzhou is 72 ～ 83 days,which has the characteristics of early maturity and the potential of early maturity combination.(2)The daily flowering dynamics of M20S showed a dynamic trend similar to “M”,with high anvil flowering rate,concentrated flowering period,long flowering duration,and high stigma exposure rate,which was conducive to the outcrossing fruit.(3)Referring to the standards issued by the ministry of agriculture(NY/T1215-2006),the initial identification of M20S infertility starting temperature is 24.0 ℃,fertility is little affected by the length of light,the infertility type is temperaturesensitive.(4)The combination of M20S has strong super-parent and control advantages,mainly in large panicle size,and short growth period duration.The combination has the characteristics of early maturity and high yield.(5)The relativity effect of general combining ability of sterility line M20S was better in 11 traits studied in the experiment.The effect of special combining ability is ideal,among which M20S/hanghui1508,M20S/taifengzhan,M20S/hanghui1173,M20S/R1033,M20S/yuexiangsimiao and M20S/R2479 are ideal.(6)The additive genetic effects of growth period duration,plant height,grain length-to-width ratio,primary branch number,panicle weight,thousand kernels weight and seed setting percentage;grain number per panicle,effective panicle number,panicle length,grain density,the non-additive genetic effects predominate;all traits are affected by both the environment and the genes.(7)The generalized heritability of traits is large to small: growth period duration > plant height > grain number per panicle > primary branch number > panicle length > grain length-to-width ratio > effective panicle number > grain density > panicle weight of plant > seed setting percentage > thousand kernels weight;The narrow heritability of traits is large to small: primary branch number > growth period duration > grain length-to-width ratio > grain density >panicle length > panicle weight of plant > grain number per panicle > thousand kernels weight > plant height > seedsetting percentage > effective panicle number.(8)The appearance quality of M20S and M20S rice was better.The chalky grain rate(9.50 %)and chalkiness(1.59 %)of M20S were better,but the amylose content was higher(22.71 %).Due to environmental and personal reasons,the combination of M20S with poor performance of average chalky grain rate(59.00 %)and chalkiness degree(20.14 %),and average amylose content(25.47 %).This study shows that: the beginning of M20S sterile temperature 24.0 ℃,is not sensitive to light cycle,belong to win min type,plant type is compact,and distributing moderate,weak tillering ability,good ear character,make dynamic performance is better;The combination of M20S had strong superaffinity and control advantages.The relativity effect of general combining force of M20S traits was better,and the effect of special combining force was ideal.The quality of M20S rice was better,but the quality of the combined rice needed further improvement.