Researches On Characteristics And Seed Glume-openging Of The Rice Parent Longke638S

Longke 638S, is a photoperied and temperature sensitive genie male-sterile rice bred by Hunan LongPing High-technology Seeds Research Institute. The major agronomic, out-crossing characteristic, GA sensitivity, critical sterility inducing temperature, combining ability and glume-gaping grains were analyzed. The main results are as follows:1. The height of Longke 638S was 90.2cm, effective panicle number was 9.2, panicle length was 20.09cm,180 grain number per panicle,1000-grain weight was 24.29g. Longke 638S showed a characteristics of dwarf stem and large panicle; And it is a middle maturity indica rice with a mature period from 86d to 91d, bred in summer. Its length flag leaf was about 40.33cm, stem clasping length was about 5.25 cm, its enclosed glumous flower was about 4.98%, its optimized density was at 150g/hm~2 and it was sensitive to GA. The critical sterility inducing temperature was between 22.5? and 23.5?; Percentage of spikelet flowing before noon was about 80%, which would be raised to 85% by Spraying GA; Stigma exertion rate was 82.57%, which would be promoted to 89.15% by Spraying GA; The stigma length to width ratio was 2.81 and the coefficient of stigma vitality was 1.28, and outcrossing rate was 3.33% after delayed pollination on the 7th day.2. The best general combining ability of Longke638S with Y58S, shen08S,1037S,33S and 095S was analyzed concerning plant height, effective panicle number, sowing-mature duration, grains per spike, seed setting rate,1000-grain weight and yield per plant. The GCA of panicle length and length flag leaf was ranked 2nd among 6 sterile lines.3. The seeds of Longke638S/R534 were divided into normal, glume-cracking, slight glume-opening, severe glume-opening and the ratio were 48.72%?25.80%?17.47% and 8.01%.1000-grain weight was 24.76g,20.84g,18.23g,11.59g and the germination rate was 93.71%,69.69%,35.89%,3.47% respectively. Under different nitrogen levels, the descending ratio of normal seed was N0> N1> N2> N3> N4; The descending ratio of normal seed that spraying with KH2PO2 was T2>T3>T1>CK, that spraying with Boron was T2> T1>T3>CK.In summary, Longke 638S harbours excellent agronomic traits, good outcrossing and combination ability; During producing hybrid seeds, the control of nitrogen fertilizer at 150kg/hm~2 was appropriate, the ratio of Glume seeds would be reduced to some extent by spraying 0.2% KH2PO4 or 0.1% Boron at the eighth stage of spikes differentiation.